naturehydro – Page 28 – Nature Agriculture

November 23, 2023

Sandwiched between the automobile bridges is a narrow pedestrian bridge

The day of my arrival in New Village, I ate lunch with many other construction workers in a private house marked with a sign saying paidang, a term referring to a low-budget restaurant for workers. The restaurant proprietor used his first-floor living room and garage for this purpose, setting up three square-shaped “eight sages” tables—each of which could accommodate eight customers. This type of table is a common piece of household furniture among farmers living in the lower Yangzi rice-growing region. I encountered several small restaurants in the New Village. Townhouse space was used for other informal businesses as well, including general stores, two majiang parlors, a computer IT repair store, and even a clothing factory. It was in one of the majiang parlors, run by an older couple in their two-story townhouse, that I first made the acquaintance of my host Mrs. Tang. During my stay, I accompanied her to this majiang parlor nearly every afternoon. The couple could make as much as USD $15 per day if all four majiang tables were in continual use. The computer repair shop, run by a young man in his 20s, was more difficult to find. Although situated in the house just behind the Tang’s, I did not notice it at first. The clothing factory, also a family-run business taking advantage of family household space, was comparatively more conspicuous. Although the majiang parlor and computer repair shop did not have signs, the name of the factory— “Jinhu Clothing Factory”—was mounted on a side wall along with an advertisement announcing that the factory was hiring experienced workers to operate the sewing machines. Even with all the above-mentioned survival strategies, many residents still cannot balance their family budgets. Thus, many young able-bodied men from Jinhu continue to migrate to distant urban centers for work. To be sure,maceta plastico cuadrada rural-to-urban migration is not a new strategy; it has been practiced by rural populations across China since the late 1980s.

As most rural young adults began to migrate to large cities for work, a great divide emerged between the productive space of cities, where able-bodied adults work in factories and in the service sectors, and the social reproduction space of villages, where grandparents take care of grandchildren, whose own parents in the factories do not have time to tend to their upbringing. In the villages, one generally encounters mostly women, children, and the elderly, often referred to as “left-behind elderly, children, and women” . The Jinhu development project was supposed to change this. Residents of the New Village were supposed to find employment at the nearby theme park. In fact, less than 100 people are employed there, with more than half of them hired from outside of the New Village. Moreover, one middle-aged woman complained to me that the developer hires his own relatives and friends for all of the higher paid positions. Residents of Jinhu are only hired as day laborers when seasonal jobs are needed, such as to cut weeds or plant trees and vegetables. As a result, to support themselves, residents have continued to find jobs far away. Mrs. Tang and her husband had both migrated to a large city in Zhejiang when I revisited Jinhu New Village in summer 2013. In all appearances, the “New Countryside” implemented at Jinhu merely reproduces the great divide between production space and social reproduction space that first emerged in the 1980s. In any case, Jinhu New Village is now, in many respects, merely a by-product of the major local development project, the Jinhu Rural World theme park. One of the most curious, even bizarre, aspects of the Jinhu site is the construction of a theme park. Not far from the New Village, a set of three bridges cross the artificial canal that separates the national highway from the theme park compound. Two of these bridges are restricted to automobile traffic, one serving as an entrance to the compound and one as an exit. Across the bridges one encounters the rectangular “Culture Plaza,” a vast space somewhat reminiscent of Tiananmen Square in appearance . Beyond the plaza is a large parking lot. Only after crossing this parking lot does one finally reach the ticket office, as well as the adjacent multi-story headquarters of the real estate development company responsible for the entire project—the Guoqiang Conglomerate.

All the elements of this entryway—not to mention the drive-in movie theater on the north side of the park—are tailored to car-owning clients, presumably arriving from large urban centers. Needless to say, the monumental entryway is also meant to impress. In order to obtain government funds and bank loans earmarked for agricultural development, the Rural World theme park is in principle designed to educate urbanites about agriculture in China. One particular focus is “natural disasters”—on the premise that agriculture is reliant on the conditions of the weather, the soil, and the natural environment. Thus, the rural theme park includes a small museum showing photographs and videos about floods, droughts, earthquakes, tornados, locust plagues, and tsunamis—all representing the various natural disasters afflicting the peasantry throughout China’s history. Associated with this theme of natural disaster—and billed as one of the highlights of visiting the park—is the“tsunami experience dome” . In contrast to the museum, which displays merely images and photographs of natural disasters, the water dome purportedly provides visitors with the “real” experience of a tsunami. Inside, visitors can surf six-meter high artificial waves generated by a wave machine. The Guoqiang Conglomerate is very proud of its innovative approach at combining entertainment with an educational experience. Indeed, Jinhu Rural World has been publicly acclaimed by both central government officials and the national media.Perhaps as part of its educational mission, the park is also a celebration of scientific management and high technology. As such, many of the park’s attractions provide insight into how agricultural development and modernization are imagined in contemporary China. By depicting natural disasters through historical photographs and videos contained within a museum, natural disasters are relegated to the realm of the historical past. By transforming tsunamis into entertainment, they become in essence domesticated by modern science. The theme of the human conquest of nature is ever present.

On either side of the vast empty plaza and parking lot is situated a large one-story green building, with signs identifying one as a “modern seedling center” and the other as an “agricultural high-tech center”. As one example of agricultural modernization, the agricultural high-tech center contains a section demonstrating hydroponic techniques for growing green vegetables, including lettuce and tomatoes. Water-drip irrigation and greenhouse farming are commonplace throughout the park. For example, the grape garden is covered with plastic,macetero de 7 litros producing a greenhouse-like environment that shelters the plants from uncontrollable nature. The grape vines are watered with a drip system and kept at constant temperature using a temperature control system. Elsewhere, delicate butterfly-shaped orchids are grown in glassware within laboratories in which staff members wear white medical coats and face masks . The park also features desert and tropical botanical gardens—containing plants like giant cacti and many exotic tropical plants—both housed within glass-roofed concrete buildings. Modern agriculture, as portrayed in the Rural World theme park, is not unlike urban modernity. Hygiene and cleanliness—represented by the face masks, lab coats, and hydroponics—are stressed. And modern agriculture is placed in a built environment almost entirely protected from the vagaries of the natural world. This modern, scientific, hygienic agriculture exists in curious contrast to another dominant theme of the park—the romanticization of the peasantry and rural life. The rural fantasy is evident in a variety of different “rural” activities in which tourists are invited to participate. It is this element of the park that is most evident when one searches for information on the internet. Numerous travel agencies based in Nanjing and Shanghai—two of the largest urban centers in Eastern China—describe nearly identical itineraries. Their websites highlight tsunami- and tornado-based water sports, as well as rural activities such as fruit and vegetable picking, watching “folk animal performances” , and growing crops in a four-by-four-meter rented vegetable plot in one of the greenhouses. Thus, during grape season, tourists can pick grapes from grape vines in the covered greenhouses, and then purchase what they have picked at a relatively high price— USD $5 to $6 per pound. The vegetable plots are rented for USD $215 per year; moreover, clients who do not wish to get their hands dirty can entrust the planting and maintenance of the crops to the theme park for an additional fee. Clients can also enjoy a variety of shows including cock fighting, goat fighting, and piglet racing. Also at an additional cost, one can go horseback riding around the park grounds. All of these fees are on top of the entry ticket of USD $25 per person. It is clear enough that what Jinhu Rural World represents is not a nostalgic recreation of traditional agricultural society; rather it is a playground for adventurous urbanites, featuring a clean, new, “modern” countryside. One key difference distinguishing Jinhu Rural World from traditional rural society is the apparent absence of peasants. In fact, at Jinhu, it is not the case that mechanization has replaced intensive farm work. Jinhu Rural World does hire local peasants to weed, prune grape vines, and grow vegetables for urbanites who rent the four-by-four plots. Yet peasants are absent from all publicity for the theme park. In the case of the vegetable plots, Jinhu’s innovative approach is to allow urbanites to monitor their plots over the internet—a form of e-commerce that Jinhu planners call “e-family farms” . Though there are peasants minding the plots, they rarely appear on the monitors; they become faceless and nearly invisible.

Peasants are not part of the new rural world. Instead, fabricated “folk animal performance,” agricultural machines, and new technologies are the key emphasis. It is as if the rural population itself is too backward to have a place in the modern new countryside. To build Jinhu Rural World theme park with no rural population in it, the Guoqiang Conglomerate embarked on a radical reorganization of village space. In 2007 and 2008, peasants had to move out of their original villages, which once dotted the landscape around the large lake now at the center of the theme park. Although the development company demolished most of the peasants’ houses immediately so that they could not be reoccupied, as of 2012, most of the fields were left fallow while awaiting the construction of the new theme park attractions. Village restructuring also involved a much more highly compartmentalized organization of space. To avoid confrontations with peasants seeking to exploit unused land, the company fenced off a large area, preventing access by all but authorized personnel. Formerly, villagers could walk anywhere, even across their neighbors’ fields. Their physical freedom of movement within villages was a longstanding part of peasant culture. Now things were different. When Mrs. Tang and her husband took me on a Honda motorcycle to see their old village, we were prevented by a guard from entering the compound, despite the husband’s angry insistence. The development of the Jinhu site involved a compartmentalizing of public and private space that led to previously unknown constraints on the free movement of villagers. Besides compartmentalization, development also entailed the labeling of space. All of the attractions in the Jinhu Rural World theme park were identified with signs. Jinhu New Village was also identified by means of the majestic gate placed at the entrance. Needless to say, local residents living in their natural villages had no need for such signs and labels. Labeling the landscape is done by outsiders and for outsiders. It is a tool used by the state to increase the legibility of the built environment. Living villagers were not the only ones to be moved. The village dead were also relocated—from graves once scattered throughout the peasants’ fields into a single cemetery just east of the new village. The Jinhu cemetery is graced with a brand-new gate just like the one for Jinhu New Village, albeit with characters written in white on black instead of in red .

November 22, 2023

The effect size in each case represents the difference compared to the water control treatment group

MS-DIAL features were clustered by applying a Pearson correlation, with a minimum correlation of 0.8 and maximum p value of 0.05, retaining two features per cluster according to most intense and the most connected peak filters . Selected peaks were imported into MS-FINDER for annotation . Mass tolerance for MS1 and MS2 were set to 5 and 15 ppm respectively, the relative abundance cut off set at 1% and the formula finder was configured to use C, H, O, N, P, and S atoms. FooDB, PlantCyc, ChEBI, NPA, NANPDB, COCONUT, KNApSAcK, PubChem, and UNPD were used as local databases. During the final merge step in MS-CleanR, the best annotation for each peak was based on MS-FINDER scores. The normalized annotated peaks list produced by MS-CleanR was used for the final statistical analyses in R. A partial least squares supervised model of the complete log-transformed and Pareto-scaled dataset was done using the ropls package , with the three treatment groups as the response variables. Ellipses were drawn around treatments using stat_ellipsebased on a 95% confidence level. This distance type considers the correlation between variables and the ellipses are created around the centroid data point. Heatmaps were created using the log-transformed data within the ComplexHeatmap package in R , with hierarchical clustering according to the complete-linkage method and Euclidean distance measure across columns and rows, displayed as dendrograms.Pairwise multivariate analysis was performed across all time points between ANE and H2O, and between AA and H2O, using an orthogonal projections to latent structures discriminant analysis . OPLS-DA models were generated using the ropls package, macetas plastico cuadradas with the predictive components set to 1 and orthogonal components to 7. S-plots were generated following sample sum normalization and Pareto scaling via calculation of p1 and pcorr1 of the OPLS-DA scores using the muma package source code within R.

Chemical class enrichment analysis was achieved using ChemRICH for each two-treatment comparison at each time point within R using the source code . A student’s t-test of the signal was conducted to generate p values and effect size. Previous transcriptomic work revealed a high level of congruency in differentially expressed genes in AA- and ANE-treated tomato seedlings compared to H2O-treated controls . To further this line of investigation, the metabolomic profiles of AA- and ANEroot-treated plants were compared to H2O after 24-, 48-, 72-, and 96-hours exposure to their respective treatments. Locally-treated roots and distal leaves were harvested, flash frozen, extracted for metabolites, and subsequently analyzed via LC-MS, which with underivatized samples primarily captures the nonvolatile metabolome . Partial least squares score plots of tomato root tissue revealed distinct clustering by treatment irrespective of time point . No overlap was observed in the 95% confidence ellipses for any treatment group. Likewise, heatmap visualization of the log10 signal of metabolites showed clear clustering of metabolomic profiles by treatment . Features displayed in the heat map were filtered from the total dataset with a p-value < 10−6 and absolute fold change > 5 in roots. Less defined clustering was observed in PLS score plots of distal leaf tissue across sampled timepoints . Ellipses representing the 95% confidence interval for both H2O and AA treatments both partially overlap with the ANE treatment group. Similarly, a heatmap depicting metabolite log10 signal showed more diffuse clustering by treatment . Visualized metabolites from leaves displayed in the heatmap used a p-value < 0.001 and an absolute fold-change > 2. These findings are refilective of distal tissue not directly treated with either elicitor. Changes in the distal leaves were not as robust as in the directly treated roots, likely due to diminution of systemic signals that effect metabolic changes throughout the plant. An assessment of the total annotated features across the metabolomic analysis revealed shared and unique annotated features between roots and leaves .

Roots and leaves share 44 features with leaves displaying the largest number of unique metabolic features . There were 330 unique identified features in leaves compared to 223 features unique to root tissue . A comparison of differential metabolic features for AA- and ANE-treated plants compared to the H2O control revealed robust overlap for both roots and leaves . AA- and ANE-treated roots shared 68 differential metabolic features, with AA and ANE treatments possessing 37 and 29 differential features unique to each, respectively . Less overlap was observed in leaves with 39 shared differential metabolites, with AA- and ANE-root treated plants displaying 34 and 19 uniquely differential metabolites, respectively .Chemical enrichment analyses were conducted to identify classes of metabolites whose accumulation was locally or systemically altered in AA- and ANE-root-treated tomato seedlings. Enrichment analyses of metabolites whose mean signal was significantly changed in AA- or ANE-treated plants compared to H2O identified numerous affected chemical classes . These changes were most robust in directly treated roots compared to distal leaves. Treatment of tomato seedlings with AA showed strong modulation of metabolomic features classified as triterpenoids and linoleic acid and derivatives in roots. AA-treated roots also showed increases in hydroxycinnamic acids and derivatives and fatty acyl glycosides of mono- and disaccharides. ANE-treated roots showed modulation in the accumulation of triterpenoids, steroidal glycosides, and hydroxycinnamic acids and derivatives. Similar to AA-treated plants, the roots of plants treated with ANE also showed increases in metabolites classified as fatty acyl glycosides of mono- and di-saccharides. Although less striking than the chemical enrichment analysis of roots, leaf tissue of root treated plants did reveal an altered metabolome . These changes in metabolite accumulation occurred most prominently at 96 hours, the latest tested time point. Increases in sesquiter penoids and steroidal saponins were seen in leaves of AA-treated plants at 96 hours.

A mix of accumulation and suppression of terpenoids and an increase of methoxyphenols was observed in the leaves of ANE-root-treated plants. Chemical enrichment analyses broadly revealed classes of metabolites that were induced or suppressed in AA- or ANE-treated plants. To examine which specific variables provide the strongest discriminatory power between the two treatment groups, a two-group comparative supervised multivariate analysis, orthogonal projections to latent structures discriminant analysis , was utilized. OPLS-DA score plots show strong between group variability discrimination between AA and ANE treatment groups compared to the H2O control across all tested time points with the x-axis describing the inter-treatment variability,macetas 30l and the y-axis showing the intra-treatment variability . S-plots derived from OPLS-DA were examined for both AA and ANE treatments in pairwise comparison with H2O control. S-plots of OPLS-DA revealed that treatment with AA or ANE induced shared changes in the levels of several defense-related metabolites in roots . Variables with the most negative and positive correlation and covariance values are the most influential in the model. These metabolites are located on either tail of the S-plot and contribute most greatly to the separation between treatment groups Bar charts depicting mean LC-MS signals for top OPLS-DA S-plot metabolites visualized across all time points illustrate that AA and ANE have similar effects on plant metabolic response . Treatment of tomato roots with AA and ANE resulted in a sharp increase in metabolic intermediates in ligno-suberin biosynthesis. This includes AA-induced accumulation of moupinamide and significant increases in coniferyl alcohol in the roots of ANE-treated plants across all tested time points. In roots,AA and ANE treatments also induced increased levels of N-ethyl phydroxycinnamide and N1-trans-feruloylagmatine compared to H2O treatment, refilecting strong upregulation of the shikimate pathway and phenolic compound synthesis. Reduced levels of tomatine and dehydrotomatine were observed in the roots of AA- and ANE-treated plants indicating suppression of steroid glycoalkaloid biosynthesis. Treated plants also showed lower levels of lyso-phosphatidyl ethanolamine that could refilect enhanced membrane lipid turnover. AA and ANE can induce disease resistance locally and systemically, alter the accumulation of key phytohormones, and change the transcriptional profile of tomato with a striking level of overlap between the two treatments . The current study examined and characterized the AA- and ANE-induced metabolomes of tomato. AA and ANE locally and systemically induce metabolome remodeling toward defense-associated metabolic features. Early studies investigating transcriptional and metabolic changes in potato revealed selective partitioning and shifting of terpenoid biosynthesis from steroidal glycoalkaloids to sesquiterpenes following treatment with AA or EPA or challenged with P. infestans . Similarly, our work here with AA- and ANE-treated tomato seedlings has shown a marked decrease in the levels of two abundant glycoalkaloids, tomatine and dehydrotomatine . Our data also show strong enrichment of sesquiterpenes in leaves of AA-treated plants at 96 hours post treatment, although the identity of these sesquiterpenes is unresolved .

This work further supports evidence for differential regulation and sub-functionalization of sterol/ glycoalkaloid and sesquiterpene biosynthetic pathways in solanaceous plants in different stress contexts . AA and EPA are strong elicitors that are abundant in structural and storage lipids of oomycete pathogens, but absent from higher plants. Although their initial perception by the plant is likely different from that of canonical MAMPs , there is some convergence in downstream defenses induced by these various MAMPs. Work to characterize the effect of canonical MAMP treatment on the metabolomes of various plant species has implicated common metabolic changes that prime for defense. Cells and leaf tissue of A. thaliana treated with lipopolysaccharide showed enrichment of phenylpropanoid pathway metabolites, including cinnamic acid derivatives and glycosides . In the same study, SA and JA were also positively correlated with LPS treatment, as we also observed in tomato following treatment with AA . Recent work in A. thaliana wild-type and receptor mutants treated with two chemotypes of LPS showed increases in hydroxycinnamic acid and derivatives and enrichment of the associated phenylpropanoid pathway . Work in tobacco similarly found treatment with LPS, chitosan, and flg22 all induced accumulation of hydroxycinnamic acid and derivatives, and that defense responses elicited by these MAMPs were modulated by both SA and JA . More recent work in the cells of Sorghum bicolor treated with LPS showed enrichment of hydroxycinnamic acids and other phenylpropanoids in coordination with accumulation of both SA and JA . Treatment of tomato with flg22 and flgII-28 also enriched hydroxycinnamic acids, and tomato treatment with cps22 revealed a metabolic shift toward the phenylpropanoid pathway with hydroxycinnamic acid, conjugates and derivatives as key biomarkers . Similar to traditional MAMPs, AA and the AA/EPA-containing complex mixture, ANE, both induce enrichment of cinnamic acid and derivatives in tomato seedlings . This supports the hypothesis that MAMPs broadly induce similar metabolic changes to enrich pools of specialized secondary metabolites that contribute to plant immunity. AA- and ANE-treated roots showed strong enrichment of metabolic features classified as fatty acyl glycosides of mono- and disaccharides . Fatty acyl glycosides have been studied in several plant families and are most extensively characterized in members of Solanaceae . Investigations into the function of fatty acyl glycosides in plants suggest they may act to protect against insect herbivory through various mechanisms and provide protection against fungal pathogens . A recent study isolated and identified fatty acyl glycosides from strawberry capable of inducing immune responses in A. thaliana, including ROS burst, callose deposition, increased expression of defense-related genes, and induced resistance to bacterial and fungal challenge . This same work also demonstrated that the strawberry-derived fatty acyl glycosides induced resistance in soybean and, due to their antimicrobial activity, also protected lemon fruits post harvest from fungal infection . AA- and ANE-root treatments locally elicit accumulation of the same class of defense associated metabolites that Grellet et al. illustrated to have direct antimicrobial activity and protect against disease . Cell wall fortification is an important plant defense often initiated upon pathogen infection. Cell wall lignification is a well-studied mechanism with localized accumulation of phenolic intermediates and lignin at attempted penetration sites . Lignification reinforces and rigidifies the cell wall to create an impervious barrier to microbial ingress . In our study, AA treatment of tomato roots induced accumulation of a phenylcoumaran intermediate in lignin biosynthesis, while ANE treatment induced accumulation of coniferyl alcohol, an important monomer unit of lignin. Interestingly, coniferyl alcohol has recently been shown to act in a signaling capacity in a regulatory feedback mechanism to intricately control lignin biosynthesis, an irreversible process that is energetically costly .

November 21, 2023

Potential agricultural losses are exacerbated by a history of pesticide resistance development

Due to such unexpected effects, accurately predicting the consequences of specific CECs, even in model insects, is not yet possible. This problem is exacerbated by a lack of information regarding effects of pharmaceuticals and other CECs on the microbial communities of any terrestrial insects. Arthropods, such as insects and crustaceans, rely on hormones to grow, develop, mate, and produce pigmentation . However, many pharmaceuticals, especially mammalian sexhormones, are structurally similar to chemicals that these organisms rely on for growth and development. These pharmaceuticals then bind to receptors and either over express or suppress their counterparts’ natural function. This has been seen in birds, reptiles, and arthropods where endocrine disruption occurs, primary and secondary sexual characteristics are modified, and courtship behaviors are changed . Although most arthropod hormones do not closely match those of mammals, their molting hormone is very similar in structure to the mammalian female sex hormone 17β-estradiol. In crustaceans, mammalian hormones have been known to cause both increased molting events and inhibition of chitobiase, the enzyme responsible for digestion of the cuticle during insect molting . In insects, 17α-ethinylestradiol, a common synthetic birth control hormone, has been shown to alter molting and lead to deformities of C. riparius . In addition to these effects,macetas de plástico pharmaceuticals have been shown to have delayed cross-generational effects . The cabbage looper is a well-studied polyphagous insect native to North America and is found throughout much of the world . T. ni are yellow-green to green in color and can complete their life cycle in as little as 21 d depending on temperature . This species is a pest on many agricultural crops including crucifers and a variety of other vegetables in both field and greenhouse settings .

Currently, there is little to no information regarding pharmaceutical effects at the concentrations found in reclaimed water on the growth or microbial community composition of any terrestrial herbivore. Many herbivores can be exposed to these contaminants after the CECs enter surface waters, soil, and plants from wastewater reuse and unintended discharge. To investigate the function of the gut microbes in insects, several studies have used antibiotics applied at high doses . There is also no information regarding effects of CECs when translocated through plants to terrestrial insects. To test the hypothesis that common pharmaceuticals affect mortality, development, and microbial communities of T. ni, we conducted a series of bio-assays in artificial diet and on a key host plant utilizing surface water concentrations of common important pharmaceuticals. We used a culture-independent approach by performing a 16S rRNA gene survey on both diet and whole-body insects. Any effects would have potentially important implications from agricultural perspectives. Also, as there is currently no information on effects of CECs on terrestrial insects acquired through a plant matrix, our findings would have possible interest for integrated pest management research.In our study, CECs at concentrations found in reclaimed wastewater were shown to increase mortality of T. ni, especially on artificial diets contaminated with antibiotics, hormones, and a mixture of the chemicals. The mortality effect was also evident when T. ni were reared on plants grown in antibiotic-containing hydroponic growth media. Because plants grown in the hydroponic system contained quantifiable levels of ciprofloxacin in the leaf tissue , and the antibiotic treatments significantly changed the microbial community of the insect , we think this is possibly a cause of the mortality but we cannot exclude direct effects of the CECs on the insects or indirect effects through the plants. Ciprofloxacin is a quinolone topoisomerase IV and DNA gyrase inhibitor that acts by stabilizing the DNA-topoisomerase IV and DNA-girase so that it is no longer reversible . This blocks DNA replication and eventually causes cell death of bacteria.

However, unlike bacteria, when higher-level organisms evolved, the A and B subunits of the topoisomerases fused, creating homodimers that cannot be targets of ciprofloxacin , and thus damage to the ribosomes of insects is not a possible mechanism of toxicity. Interestingly, we did not see the increased time to adulthood in T. ni reared on plants compared with those reared on contaminated artificial diet. We postulate the discrepancy is possibly due to a number of factors such as dilution of CECs, as they were acquired from the water by the plants or there was bio-degradation of the chemicals occurring in the plant or by photo degradation. However, recent studies have shown pharmaceutical concentrations in surface waters, which appear to remain constant over the course of several years . More studies would be needed to determine how CECs at concentrations found in reclaimed water for agriculture would interact with current IPM strategies , and how soil matrices would affect the chemical acquisition and translocation by plants. Many insects rely on microbial communities and endosymbionts to grow and develop; however, it has been shown that Lepidoptera species do not have a vertically transmitted microbial community. In addition, because the effects of microbial communities on T. ni survival and development have not been documented, we present these data only to show that microbial communities change when exposed to CECs, and not as a proven factor influencing survival. We found significant shifts in the microbial community in the various life stages examined within the control treatments notably from third instar to subsequent life stages. A similar result has been reported for mosquitoes and other insects . However, there is one family, Lactobacillaceae, which appears in all treatments and life stages in high proportions, except for adults. They are fairly common in insects and can be responsible for at least 70% of the bacterial community .

Lactobacillaceae is responsible for ∼42% of the bacteria in all life stages, followed by Pseudomonadaceae, Alcaligenaceae, and Enterobacteriaceae. Lactobacillaceae have been shown to act as beneficial bacteria in Drosophila ; however, its function in T. ni is still unknown. Alcaligenaceae has been shown to be present in other moths , but Lepidopterans are not thought to have a functional microbiome . There are clear patterns regarding the changes in microbial community proportionality according to the heat map . In controls, third-instar microbial communities are relatively evenly spaced by family. The microbial community becomes predominately Lactobacillaceae for sixth instars and pupae. Once the insects reach the adult stage, their most predominant family is Pseudomonadaceae. This pattern holds in the acetaminophenand caffeine treatment groups as well. Interestingly, the other treatment groups do not share this pattern. For antibiotic- and hormone-treated T. ni, Lactobacillaceae is the predominant microbial family in the immature stages, but at the adult stage microbial community reverts to predominantly Pseudomonadaceae. We suspect that this is because,cultivo del frambueso once the larvae undergo metamorphosis and shed their gut contents in preparation for pupation, they are no longer exposed to the pressures exerted by the CECs on the microbial community. Fig. 3 provides a visual indication of the changes in the bacterial communities over time. The increase in β diversity after eclosion could be due to the larvae no longer being exposed to CECs or diet-borne bacteria after being moved to sterile containers. Also, when bacteria are lost as larvae digest their gut contents during pupation, the microbial β diversity could change. Interestingly, the hormone-treated T. ni follow a similar pattern to those exposed to antibiotics, but their ellipses are always much smaller, suggesting the entire insect population is showing a uniform response within their microbial communities. However, in the mixture-treated insects, larvae displayed a greater average diversity in their microbial community structure than either pupae or adults. This finding has not been shown in any single category of treatment, and we suspect the microbes exposed to mixtures could be experiencing potential interactive effects among chemicals . Such interactions should be the focus of future studies along with investigations of plant rhizosphere bacteria, particularly since we found a difference in the Bradyrhizobiaceae family for all treatments. These results show that a terrestrial insect pest of commercial crops can be affected by CECs found in reclaimed wastewater for agricultural use. Our results suggest that CECs found in wastewater can impact T. ni growth and development, survivorship, and alter their microbial communities. Because T. ni is a common agricultural pest found around the world, feeds on a wide variety of plants, and has a history of developing pesticide resistance, its ability to deal with toxins is likely higher than many other insects.

In addition, the responses we observed to CECs could have interesting implications for IPM practices on plants such as lowering the amount of pesticides needed or increasing susceptibility to insect pathogens, as has been shown in mosquitoes . These potential effects may be understated because some insects cannot detect the presence of the pharmaceuticals . However, we do not recommend purposefully exposing crops to CECs specifically for the control of insects because our study documented that these pharmaceuticals are translocated into crops and we do not yet know their possible effects on humans if consumed . We specifically want to note that ingestion of these compounds through uptake and translocation by a plant is not the only way T. ni or any other insect would be exposed to these compounds. Overhead sprinkler irrigation could cause contact absorption by the plants or insects, and simply drinking water on leaves at contaminated sites could expose insects to higher concentrations than were found in plant tissues. In fact, the ciprofloxacin concentration used was less than one-third of the highest rate . We urge caution in extrapolating to plants growing in soil, because variation in soil type and potential soil bacterial degradation could affect persistence [although soil bacteria are often negatively impacted by CECs ]. However, CEC exposures are considered pseudopersistent because they are reapplied with each irrigation. Thus, the effects reported here are likely to be conservative. Additional studies with other insects, particularly those with other feeding strategies, will be necessary before any patterns can be discerned.The majority of these associations are with arbuscular mycorrhiza fungi which penetrate into root cortex cells to form highly branched structures . The investment of photosynthetic carbon by plants to AMF is rewarded with increased nutrient availability made possible by the extended hyphal network in the soil. For instance, up to 90% of phosphorus uptake in plants can be contributed by symbiosis with AMF . AMF networks in the soil also influence water retention and soil aggregation further impacting plant growth . Moreover, next-generation sequencing technologies and advances in imaging techniques have greatly improved our knowledge on the taxonomical and functional properties of fungal communities in the rhizosphere . However, these methods are optimized for fine scale analysis and are not capable of assessing the foraging capabilities of hyphal networks which can span across centimeter to meter scales. Toward this end, several researchers have used compartment setups with physical barriers created by 20–37 µm nylon membranes which restrict movement of roots but not mycorrhizal fungi. This separation creates root-free and plantfree soil compartments connected only by mycorrhizal fungi to examine the transport of various compounds across these compartments. Using this set up, the importance of mycorrhizal fungi in the flow of different elements such as carbon , nitrogen and phosphorus between plants, soil and microbes over centimeter distances have been validated. Repeated disruption of the hyphal connections also led to a decreased resistance in plants to drought stress . The membranes can also be placed horizontally to create different depth gradients to investigate hyphal contributions to water uptake . In some studies, an additional 1.5–3 mm air gap is created between two membranes with a wire net to restrict solute movement between two chambers . A common feature of these set ups is the size-exclusion membranes which proved to be critical in distinguishing fungal hyphae processes in the rhizosphere soil. In addition to AMF interactions, a split root set up, which separates the roots of one plant into halves, can be introduced to investigate the systemic response of plants . In essence, the split-root system directs the growth of the roots to generally two different growth conditions and enables the investigation of whether a local stimuli have a local or global response which can be observed at the root or shoot level .

November 20, 2023

The developmental time was rescued by reintroducing bacteria from the genus Asaia

Over expression of ecdysone during development could explain why BPA causes mouth deformities and increased pupation time in C. riparius 11. In mosquitoes , the vitellogenin gene is a target for ecdysteroid receptor, which can be modulated by the xenoestrogen BPA. This suggests that BPA and other xenoestrogens could have an effect on the production of vitellogenin, the egg yolk protein. This also would lead to altered viability of offspring, which we did not assess. Acetaminophen and the mixture of PPCPs significantly slowed developmental time of C. quinquefasciatus, but antibiotics alone did not. In contrast, Chouaia et al.described delayed larval development of Anopheles stephensi after treatment with the antibiotic rifampicin at 120 µg/ mL. In our study, there was relatively little difference in development of immature mosquitoes between the antibiotic treatments and the controls for the Acetobacteraceae, to which Asaia belongs. It is possible that the antibiotics chosen for this study are not effective in eliminating Asaia. Alternatively, the antibiotics in our study were used at doses much lower than the rifampicin tested by Chouaia et al., and might have achieved similar effects if applied at higher doses. With a combination of antibiotics, hormones and other constituents that occur in PPCP-contaminated reclaimed water, it is difficult to know exactly which chemical is affecting which bacterial family and which bacteria were responsible for the deleterious effects on developmental time. Notably, the antibiotic treatments had approximately 1/3 of the total number of bacteria relative to the control. Therefore even the approximately 8500 counts of Rickettsiaceaein the antibiotic treatments are lower in number than the Enterobacteriaceaefound in control treatments. Surprisingly,macetas de plastico the substantial loss of bacterial counts in the antibiotic only treatments did not slow development.

Although the antibiotics decreased overall bacterial counts in C. quinquefasciatus, W. pipientis appeared to be relatively unaffected. Wolbachia pipientis is susceptible to doxycycline and rifampin. Of the chemicals we tested, oxytetracycline should have had the most impact on Wolbachia. However, because the bacterial counts were relatively similar for W. pipientis in all treatments, we suspect either the oxytetracycline was too dilute to have an effect, it allowed a non-susceptible strain of W. pipientis to dominate, or it is simply ineffective against W. pipientis. However the vast majority of the eight bacterial families were greatly reduced in the antibiotic treatments. Of these families, Enterobacteriaceae and Microbacteriaceae were the most reduced in both the antibiotic and mixture treatments. The family Enterobacteriaceae is highly associated with insect endosymbionts, such as Buchnera in pea aphids. Buchnera bacteria are known to aid the aphid by supplying essential amino acids lacking from a nutritionally deficient diet. Without these endosymbionts the aphids do not develop properly, but the microorganisms apparently have no other direct biological effect on the aphid. The size of the Enterobacteriaceae populations probably had a minimal effect on larval developmental time, as thecounts in the acetaminophen treatment are relatively similar to the hormone-treated group. Additionally, the hormone treated group has a substantially reduced count of Enterobacteriaceae bacteria compared to the control, but showed no significant changes in developmental time. We suspect, therefore, that the acetaminophen is negatively impacting some other biological system in the larvae, but determination will require additional research. The use of reclaimed water for crop irrigation and the release of water from waste treatment plants and farm waste ponds into surface waters is occurring and likely to escalate as demand for fresh water increases. While, the research reported here suggests that PPCPs contaminating reclaimed water will have potentially useful effects for mosquito control, if the data can be extrapolated to other insect species, PPCPs will also have unintended negative effects on other aquatic insects. Very little is known regarding how these contaminants might bio-magnify or change chemically as they move through the food web. The eventual impact on populations is also unknown. Further, combinations of PPCPs may be more important for some insects than individual components.

Additional research is needed not only on aquatic insects living in surface waters, but also on uptake by plants and associated herbivores in terrestrial environments.Endosymbionts, bacterial species known to grow, develop, and vertically transmit in an organisms’ cells, usually for mutualistic symbiosis, are essential to the growth, development, and fecundity of many insect species. Many aphid species, such as Acyrthosiphon pisum, Megoura viciae, and Myzus persicae, rely heavily on endosymbionts to survive on the unbalanced diet of phloem sap. Their bacteriocyte endosymbiont, Buchnera spp, provides essential amino acids. Without Buchnera, aphids demonstrate reduced growth rates and development and produce few or no offspring. However, some endosymbionts in the genus Wolbachia are known to manipulate insects for their own benefit and can also lead to increased vector competency for transmission of human diseases such as West Nile Virus. Wolbachia species are common vertically transmitted endosymbionts in many mosquito species and typically infect reproductive tissue. There are many species of Wolbachia that influence a variety of insect behaviours and life-history traits. Some endosymbionts can also act defensively by killing parasitoid eggs after they are laid in the host . Because endosymbionts play major roles in insect development, they have been proposed for use in insect control . Due to the importance of endosymbionts for development in many insect species, some species vertically transfer endosymbionts . For example, Estes et al. describes the microbiome of dung beetles’ brood balls, which are used to nourish their offspring until they are adults. When the microbiota in the beetle offspring and their female parent were compared in sterilized dung and soil, they had proportionally identical 16S rRNA sequences from their microbiome. Interestingly, over their life stages, the proportions of the families of bacteria in the beetles’ microbiome changed. The predominant family of the first three instars varied by individual. However, from the pupal stage onwards, Enterobacteriaceae was the most common family in the dung beetle. Bees acquire important bacteria through social interaction and also from the environment . Without some of these bacteria, it is thought that honey bees could become more susceptible to outside diseases and increase incidents of colony collapse .

More studies are needed to fully understand the importance of microbiota in mosquitoes as they have been linked to increased transmission of pathogens from mosquitoes to humans. Mosquitoes are common disease vectors, which spend their juvenile stages in aquatic environments . Bacteria from the water, both symbiotic and free-living, have been shown to influence the microbiome of mosquitoes, suggesting that some of their possible endosymbionts are collected from the environment . Consequently, if the environment is altered, and some of these necessary bacteria are reduced/eliminated, there could be detrimental effects on the development of mosquito larvae. Such a removal effect may occur as the result of antibiotic runoff or other pollution,macetas rectangulares and/or environmental changes. For example, Rosi-Marshall et al. showed that common pharmaceuticals in streams will alter the respiration and diversity of biofilms. Pennington et al.reported differences in whole-body micro-biomes and increased developmental times for Culex quinquefasiatustreated with various pharmaceuticals and personal care products .Chemicals intended for human use often occur in aquatic environments and/or enter water supplies through water treatment plant overflow or from use of reclaimed water in water scarce areas. These chemicals can then affect bacterial communities in the water and the associated aquatic insect community. Presence of these contaminants can alter effectiveness of Bacillus thuringiensis subsp. israelensisa pesticide commonly applied for mosquito control . However, little is known about how such contaminants will influence the microbiome of such insects. Similarly, there is a lack of data determining if mosquito bacterial communities vary during the course of larval development; all available studies we are aware of examine only late instar larvae or mixed lower in stars and species, and information regarding mosquitoes’ endosymbionts and their function is very limited or non-existent outside of Wolbachia. Therefore, we describe the differences in the bacterial communities of the mosquito C. quinquefasciatus in multiple distinct larval stages, as well as when these mosquitoes are reared in environments contaminated with ecologically relevant concentrations of PPCPs that commonly occur in combinations in order to provide a baseline for more in-depth studies. In preparation for sequencing, three mosquitoes from each PPCP treatment were collected as second, third and fourth instars, as first instars were too small to collect without damage, and twice washed with 95% ethanol to remove any external microorganisms. Larvae were then transferred to individual sterile 2 mL microcentrifuge tubes with 95% ethanol and stored at -60 ± 3°C in an ultra cold freezer until DNA extraction. DNA was extracted using a Qiagen DNeasy® Blood and Tissue Kit following the manufacturers protocols amended as in Pennington et al.. In addition to mosquitoes, samples of water and water plus diet were also extracted using identical protocols, with the additional step of centrifugation at 2900 rpm in an IEC HN-SII tabletop centrifuge for 1 h to create a pellet. Upon extraction, nucleic acid concentration was quantified using a Nanodrop ND- 2000c Spectrophotometer , to confirm enough genetic material for sequencing. This process revealed no DNA in water or water and diet samples when no mosquitoes werepresent and thus they were not subjected to further analysis because any bacteria would have originated from the mosquitoes, their egg-rafts, or from the air after the water had been altered by the mosquitoes’ various biological processes. Roche 454 bacteria barcoded amplicon pyrosequencing was performed by a commercial sequencing facility .

The procedure used the forward primer 27Fmod and the reverse primer 519Rmodbio in a single-step 30 cycle PCR using HotStarTaq Plus Master Mix . PCR was performed using the following cycle conditions: 94°C for 3 min, followed by 28 cycles of 94°C for 30 s; 53°C for 40 s, 72°C for 1 min; and a final elongation at 72°C for 5 min. After PCR, all amplicons were mixed in equal concentrations and purified using Agencourt Ampure beads . Samples were then sequenced with Roche 454 FLX titanium instruments and reagents following the manufacturer’s guidelines.Operational taxonomic units were chosen by the default 97% identity threshold, which roughly correlates to species , via the UCLUST method as implemented in the pick_otus.py script . Representative OTUs were chosen using the pick_rep_set.py script and default settings. The Greengenes reference database clustered at 97% identity was used to assign taxonomy using the assign_taxonomy.py script. OTUs were counted and summarized using the make_otu_table.py and summarize_taxa.py scripts respectively.There were 658 distinct OTUs at the species level with 58 distinct families; OTUs failed to match any contained within the database and could not be assigned taxonomically. Fifteen families were chosen by their proportionality being greater than or equal to 1% in at least one sample. The cut-off was chosen at 1% as this was assumed to be the minimum to influence larval development. For alpha diversity, multiple rarefactions were performed using the multiple_rarefaction.py script with the lowest rarefaction depth of 2000, the highest rarefaction depth of 21000, a step size of 1000, and a replicate number of ten, which normalizes the data at each depth. Alpha diversity was calculated using the alpha_diversity.py script with the metrics observed species and Shannon Indices. Alpha diversity data was not averaged between replicate mosquitoes as they have been averaged by resampling-replicates and the complications and validity of this is still being considered. Metrics were summarized using the collate_alpha.py script. Statistical analyses were performed using R . Following processing through the QIIME pipeline, “Permutational MANOVA” in the Vegan package was used to compare the OTU data. Independent variables were instar , PPCP treatment and the interaction of the two, with three replicates of each instar in each PPCP treatment and control . PERMANOVA is analogous to MANOVA but is suited to address the non-normality that is commonly associated with count data in ecological community and genetic data . Microbial community data were further examined via principal component analysis performed in the FactoMineR package . PCA and PERMANOVA were conducted on each instar in the individual PPCP and control treatment groups. Following PCA, variables were examined for their contributions and correlation to each of the first two dimensions. Those variables that were ≥ 85% correlated were included in subsequent pairwise comparisons by instar in their respective treatment.

November 17, 2023

The effect of the minerals on the activated carbon on NO adsorption efficiency was studied

Parametric studies on the production of activated carbon and the adsorption of NO by the carbon have been conducted. The optimal conditions and effectiveness of this procedure to regulate NO emissions have been determined.The activated carbons were characterized by the measurement of their average pore size and surface area. There are three types of pores which can develop in the carbon particles: micro-pores , mesopores and macropores . BET surface area of wheat straw char carbonized at temperatures between 300°C and 700o C is shown in Fig.3. The surface area passes through a maximum of 105.2 m2 /g at a pyrolysis and activation temperature of 600o C and 650o C respectively. The BET surface area of sweet potato stalk exhibits similar behaviors as that of wheat straw, being 88.1 m2 /g, 84.7 m2 /g, and 132 m2 /g at a pyrolysis temperature of 300°C, 400°C, and 600°C, respectively. The decrease in surface area beyond 600°C is caused by sample burning off. Using temperatures much lower than 600o C would compromise the maximum amount of effective adsorption surface area attainable . It is not only important to run reactions at temperatures low enough to prevent burn off and ash formation but also high enough to generate effective surface areas, which would be at 600o C for wheat straw. Fig.4 shows the BJH adsorption cumulative pore area of wheat straw activated carbon generated at different pyrolysis and activation times. It is evident from the plot that samples derived from longer pyrolysis and carbonization times exhibited a higher micro-pore count compared to shorter times. As with temperature generation optimum, however,greenhouse pot too long pyrolysis and activation reaction times cause an adverse increase in burn off percentage. Though wheat straw carbonized with a pyrolysis time of six hours and activation time of 2 hours still demonstrated a higher cumulative pore area than the shorter times, it also produces larger amounts of burn off. Since reaction temperatures were kept below 600o C, ash formation that would have diluted effective surface area was prevented.

Even though ash does not form, pyrolysis and activation times must still be chosen to create a balance between pore formation and burn off, one that would generate a high micro-pore count but at the same time, minimize material loss. The optimal pyrolysis and activation times for wheat straw are 2 hours and 1 hour respectively.Optimal pyrolysis and activation temperatures and times for carbon preparation were determined based on the amount of NOx that can be adsorbed by the activated carbon. The adsorption capacities of wheat straw activated carbons generated by different pyrolysis and activation temperatures are shown in Fig.5. A gas mixture containing 250ppm of NO, 5% O2, 10% CO2, with N2 as the balance was passed, at a flow rate of 250ml/min, through a turbular reactor containing 2g of activation carbon at 25o C. It is evident from the plots that the WS-2-600-1-650 activated carbon had the best adsorption efficiency. Samples carbonized above 600o C have higher ash concentrations than those carbonized below, while those carbonized below have lower percent micro-pore counts and surface area—both explaining why wheat straw generated at 600o C had the best adsorption efficiency. The NO adsorption efficiencies of wheat straw samples carbonized by differing pyrolysis and activation times are shown in Figure 6. It is evident from the plots that activated carbons carbonized by prolonged pyrolysis and activation times have better adsorption efficiencies than those carbonized by shorter times due to higher pore count and BET surface area. The micro-pore count and the surface area of activated carbon increases with an increase of the preparation time, which explains why the samples with the longest pyrolysis and activation times have the best adsorption efficiencies. However, prolong activation results in more burnoff and the production of ash. A balance must be reached when setting reaction parameters, one that will generate the largest surface area without a significant burnoff. We have found that the optimal pyrolysis and activation times for wheat straw are two and one hour, respectively. The hydroponic biomass possesses high mineral content. The activated carbon was first soaked in water to dissolve the soluble minerals and then dried to remove the moisture from the carbon particles. The adsorption experiments using the mineral-free activated carbon were performed and the results indicate that the NO adsorption efficiency was substantially improved .

A 100% NO removal efficiency was obtained for the entire 2 hr experiment, using a gas mixture containing 250 ppm NO and 10% O2 and at a W/F of 30g.min.L-1. The improved NO removal efficiency by the activated carbon with mineral removed is attributed to the increase of the carbon surface area, which was otherwise covered by the minerals. Because of this finding, the parametric study on the NO removal efficiency was performed mostly with the activated carbon having mineral content removed by water dissolution. The adsorbed NO can be desorbed from the activated carbon if temperature of the carbon bed is raised. Further increases of temperature results in the reduction of NO by activated carbon to produce N2. Simultaneously, the activated carbon is regenerated as a result of the reduction of NO to N2. Experiments on the reduction of the adsorbed NO by the activated carbon were performed by heating the NO saturated carbon under anaerobic conditions. In order to evaluate the behavior of the process over time, a purge gas flow of 1.0 L/min N2 was passed through the carbon bed and subsequently directed to the NOx analyzer. Desorption was conducted with a temperature ramp rate of 40°C/min from room temperature to 600o C. As the temperature of the carbon bed was increased, NO was desorbed from the surface of the activated carbon. Further increase of the temperature results in the reduction of NO by the activated carbon to N2. The fraction of the adsorbed NO that is reduced to N2 can be calculated by subtracting the NO coming out of the carbon bed from the total amount of NO adsorbed. The fraction of the adsorbed NO that is reduced depends on the temperature and the flow rate of N2 gas. Fig.13 shows the fraction of the desorbed NO integrated over the temperatures as the temperatures of the carbon bed was raised. As can be seen, the fraction of the total NO desorbed as NO was less than 100% of the total NO adsorbed, 38.5% and 9.1% for sweet potato and wheat straw activated carbons, respectively. The difference of which is attributed to the reaction of NO with the activated carbon to form N2. From the desorption curve as a function of temperature, the NO desorption mainly took place at temperature below 450°C, while the NO reduction by carbon occurred at temperature above 450°C,30 plant pot the higher the temperature the more effective the reduction is. Another set of experiments were performed to study the reduction of NO by activated carbon as a function of temperature and W/F, the ratio of the amount of carbon to flow rate of N2.

In this study, temperatures were varied between 300 and 500°C and W/F between 10 and 40 g.min/L. Fig.14 shows that, in the case of the sweet potato activated carbon, 100% of NO was reduced to N2 at 500°C with a W/F above 10 g.min./L, while at 450°C it would require a W/F above 30 g.min./L. For wheat straw activated carbon, NO can be reduced to N2 at lower temperatures and smaller W/F ratios than those of sweet potato . All inlet NO was reduced to N2 at 450°C with a W/F above 15g.min.L-1. Higher temperatures or larger W/F ratios are favorable for NO reduction. The NO reduction efficiency also depends on the concentration of NO in the system. Fig. 16 shows NO reduction by sweet potato and wheat straw activated carbons at 450C with two inlet NO concentrations, 250 ppm and 1000 ppm. The results indicate that the higher the inlet NO concentrations, the smaller the fraction of the inlet NO is reduced at a given W/F. All of inlet NO was not reduced to N2 by the sweet potato activated carbon until the W/F reached 30 g.min/L and 40 g.min/L for 250 ppm and 1000ppm of inlet NO respectively. The activated carbon made from wheat straw can reduce NO more effectively than that from sweet potato. The entire inlet NO was reduced by the wheat straw activated carbon with a W/F of only 15 g.min/L and 30 g.min/L for 250ppm and 1000ppm of NO, respectively. The space maximum allowable concentration of NO in a human occupied cabin is 4.8ppm. Experiments were conducted to determine conditions for NO adsorption on SP-2-600-1-650 at room temperature such that the NO concentration exiting the carbon bed is less than 4.8ppm. The activated carbons before and after the removal of minerals with water dissolution were both examined. The parameters studied included inlet oxygen concentration , and carbon weight to flue gas flow rate ratio . The time that the carbon bed can hold before the NOx concentration exiting the bed exceeds the SMAC will be called SMAC time. Fig.17 and 18 show that the SMAC time for both activated carbons increase with the increase of W/F and oxygen concentrations. The removal of minerals from the activated carbon increases the surface areas and results in a much longer SMAC time. The SMAC time was 22 min., 30 min., 36 min., and 62 min. with a W/F of 45 g.min/L when flue gas contains 5%, 8%, 10%, and 15% O2, respectively using the activated carbon containing mineral. However, the SMAC time was substantially increased to 145 min, 215 min, 330 min, and 500 min at a W/F of 45 g.min/L with flue gas containing 5%, 8%, 10%, and 15% O2 using the activated carbon with mineral removed. Experiments were conducted to determine the effects of the regeneration on activated carbon in terms of NO removal efficiency, as assessed by the carbon’s SMAC time. The results indicate that regeneration improves the removal efficiency of NO. This phenomenon is attributed to the increase of surface area and micro-pores of the activated carbon. However, it was observed that additional carbon burns off occurs during regeneration, which causes the overall amount of activated carbon to decrease after each regeneration cycle. The loss of mass were determined to be about 0.99% for wheat straw and 0.49% for sweet potato stalk activated carbon per cycle of regeneration at 600°C. Lastly, due to the extent of the mission, the sufficiency of the amount of inedible biomass in providing the activated carbon for the life support systems should be assessed. With a six person crew, such as the mission planned for Mars, the average food consumption is about 0.25kg/d per capita . Six people would need 1.5kg of wheat per day. Wheat straw yield depends on the specific varieties harvested and is widely affected by agronomic and climatic factors. An average ratio of 1.3 kg of straw per kg of grain is found for most common varieties . Burnoff accounts for about 66.7% at 600o C in pyrolysis and 650o C in activation, while the loss of carbon mass from soaking and drying was determined to be about 14.4%. So as a result, 203kg of wheat straw activated carbon can be produced per year. By incinerating feces, inedible biomass and trash, between 3g and 30 g of NOx can be produced per day, depending mostly on the amount of nitrogen in the inedible biomass. The range in the amount of NOx produced covers 90% pre-treatment removal of nitrogen to no pretreatment . . About 10% of nitrogen in the waste forms NOx . Regeneration of the adsorbing activated carbon shall occur once a week via the reduction reaction. The loss of carbon mass was determined to be about 0.99% at 600o C per cycle of regeneration, After one year, all the activated carbon should be incinerated and replaced. Calculations based on the above assumptions yield 210g NO emissions per week, and the adsorption capacity of NO by the activated carbon is 5.46mg/g carbon, which will need at least 38.5kg of wheat straw activated carbon all year long. These can be distributed among one adsorption tank, just with a load of 64.6kg of wheat carbon in the beginning of the year. Every week, the tank should been regenerated.

November 16, 2023

BER is characterized by water-soaking of the tissue and cell death in the blossom-end pericarp

Blossom-end rot in tomatoes and peppers causes significant losses in the vegetable industry each year. This is followed by blackening and sometimes drying of the affected tissue. BER occurs during fruit development prior to physiological maturity. While calcium deficiency in fruit tissue and abiotic stress can increase BER, the biological mechanism of cell death remains unknown and current treatments are not fully effective. Many previous studies on the biological drivers of BER development in tomatoes and peppers have relied on comparing measurements from BER affected fruit to healthy fruit. This approach has identified several possible causes of cell death. Comparing BER affected tomatoes grown in a low calcium hydroponic solution to healthy fruit grown with a higher calcium hydroponic solution, Mestre et al. found a reduction in glutathione content, glutathione reductase activity, and catalase activity. Increased hydrogen peroxide and lipid peroxidation were also associated with BER affected fruit. Aloni et al. found depleted apoplastic and symplastic ascorbic acid contents and increased apoplastic ascorbate oxidase activities in BER affected peppers compared to healthy peppers. An investigation of intracellular wash fuids by Turhan et al. found increased hydrogen peroxide concentration and peroxidase activity in BER affected fruit compared to healthy fruit. While these results strongly support the trend of increased oxidative stress during blossom-end rot development, the conclusions thus far are mainly correlative in nature. Trough over expression of a vacuolar calcium importer, de Freitas et al. found that increasing vacuolar calcium and decreasing apoplastic calcium increased BER development in tomatoes. These results suggest that decreased apoplastic calcium can lead to BER development,raspberry plant container though the hypothesis that adequate apoplastic calcium incurs a protective effect has not yet been tested.

Additionally, confounding factors at the whole plant, fruit, and cellular level make it difficult to determine the sequence of events leading to cell death during BER development. To eliminate these confounding factors and establish causative evidence regarding the biological cause of BER, direct manipulation of the apoplastic calcium concentration and antioxidant capacity is needed. Pericarp discs have been used previously to study ripening in tomatoes. Te fruit used in these experiments were at the mature green stage and the discs studied during these experiments followed ripening trends regarding physiology, visual appearance, and original tissue location. This paper describes a new method for studying BER development in immature tomatoes using the pericarp disc system.Immature green tomatoes showing no symptoms of BER were observed to develop BER symptoms during storage after harvest, if harvested just prior to the usual timing of BER development on the plant . BER development of the plant occurred within the first 3 days after harvest and the symptoms resembled BER regarding location and visual development. These results were replicated with 21-day old fruit of the HM variety and in the Rutgers variety.Pericarp discs were made from the stem-end, blossom-end, and columella tissue of immature HM tomatoes 21 days after pollination . During the first 12 h of storage, disc color lightened slightly and developed a “frosted” appearance as described previously. In discs made from stem-end pericarp, this appearance remained the same for 4 days. In blossom-end pericarp discs, symptoms developed resembling the progression of BER development on the plant. Water soaking of the tissue was first observed on day 2 of storage, usually followed by tissue darkening. While water soaking often started on day 2, initiation of water soaking also occurred on day 3 and 4 in some blossom-end discs. Water soaking and tissue blackening was initially localized to one area of the disc, and subsequently spread to the rest of the disc, as observed in Additional file 2: Video S1. An example of these symptoms is shown in . These results were replicated in Rutgers and Ailsa Craig tomatoes . Darkening in top discs was observed only when the discs were excessively handled for color or weight loss analysis, and was visually similar to symptom development in blossom-end discs. In columella discs, symptoms developed similarly to that of pericarp discs.

Discs taken from closer to the stem-end often maintained a green-white appearance, while discs taken from near the blossomend darkened over the 4-day storage period . In blossom-end pericarp discs made from fruit already showing BER symptoms, the blackening spread from the BER affected area to the non-affected area. HM and Ailsa Craig tomatoes produced the most consistent results . Rutgers tomatoes were more susceptible to symptom development at sites of damage from handling in stem-end discs .Color was measured in HM discs and whole fruit harvested with BER symptoms . L* and a* values were used to quantify darkening and loss of green color, respectively. Visual evaluations of symptom development in discs were also completed for comparison . Discs exhibiting symptoms and BER tissue in whole fruit harvested with BER symptoms had lower L* values and higher a* values than stem-end discs or the stem-end of whole fruit harvested with BER symptoms. Blossom-end discs that did not develop symptoms had similar values to those of the stem-end discs.HM disc weight loss over a 4-day storage period was not significantly different between stem-end discs and asymptomatic blossom-end discs . Discs with a visual symptom rating of 2 had significantly higher weight loss than asymptomatic blossom-end discs and stem-end discs. Weight loss in Rutgers discs was higher than HM discs. Weight loss for stem-end, side, and blossom-end Rutgers discs was slightly higher from day 2 to day 3.5 than day 0 to day 2 . Weight loss in columella discs was similar from day 2 to day 3.5 and day 0 to day 2.Enzyme analysis and color measurements were taken after 4 days of storage on 24 top and 24 bottom discs. A Pearson correlation analysis between enzyme activities and color measurements from HM discs showed that both pyrogallol peroxidase and ascorbate oxidase were significantly negatively correlated with L* values and positively correlated with a* values . Te mean ascorbate oxidase activity was 193.8 nmol min−1 g−1 . Te mean pyrogallol peroxidase activity was 11.7 μmol min−1 g−1 . Both ascorbate oxidase and pyrogallol peroxidase activity means were significantly higher in blossom-end discs compared to stem-end discs.

Treating discs with a 15 min soak in either 10 g/L calcium chloride or 500 mM ascorbic acid was effective in inhibiting the development of visual symptoms. Both visual evaluation and color data indicates that symptoms only developed in deionized water pH 5.58 and DI water pH 2.00 treated discs. Ascorbic acid treatment caused a mild loss of green color as seen in the slight increase in a* value compared to calcium treatments. Aside from this color change, ascorbic acid and calcium treated discs appeared healthy with no water soaking or darkening. Discs treated with DI water pH 2.00 showed water soaking and tissue degradation, and exhibited a gray color. Gray color development became apparent 3 days after harvest and disc formation, and became more noticeable on day 3.5, similar to the timing of tissue darkening observed in DI water-treated discs. In addition to 15 min soaking treatments, vacuum infiltration was tested as a method for inducing the uptake of treatment solutions. However, vacuum infiltration was found to induce a translucent and water-soaked appearance in all treatments, making water-soaked symptoms associated with blossom-end rot hard to identify . Te vacuum infiltration method was not pursued further.Symptom development in harvested whole fruit and disc systems closely resembled symptom development in tomato fruit on the plant. Harvested whole fruit developed symptoms only at the blossom-end of the fruit. Similarly,container raspberries only discs from the blossom-end of fruit developed symptoms in the pericarp disc system. Similar to trends in whole fruit, columella tissue taken from near the blossom-end of the fruit developed BER like symptoms while top columella tissue often did not develop symptoms. Visual BER symptom development in whole fruit on the plant begins with water soaking of the tissue at the blossom-end, usually in one or a small number of spots. Water-soaked tissue begins to darken until it has a blackened appearance. In discs, symptoms developed in a similar manner, starting with the development of a water soaked and somewhat translucent appearance. Water soaked areas then darkened. Drying of the affected tissue in discs was limited, likely due to the high relative humidity environment, though weight loss evidence suggests that increased water loss can occur during symptom development.

Drying of the BER affected area is also common in fruit that develop BER on the plant.Ascorbate oxidase activity was used as a measure of the overall trend in antioxidant depletion in BER affected fruit. Maintaining ascorbic acid concentrations in fruit has been suggested as key to BER resistance and increasing ascorbic acid concentrations in vulnerable fruit tissues is a possible treatment to inhibit BER incidence. However, conflicting ascorbate concentrations have been reported in BER fruit compared to healthy fruit. Tus, direct measurement of ascorbic acid is an unreliable indicator for the state of the antioxidant system and was deemed inappropriate for the purpose of comparing BER processes in whole fruit to symptom development in discs. Alternatively, ascorbate oxidase activity has been shown to be increased in BER affected peppers compared to healthy peppers. In tomato, ascorbate oxidase was found to be transcriptionally upregulated in fruit treated with the BER-inducing phytohormone gibberellin. Additional file 3: Figure S2 shows ascorbate oxidase activity in healthy top, healthy bottom, and BER affected pericarp tissue from BER affected fruit, and healthy top and healthy bottom pericarp tissue from BER unaffected fruit. This data indicates that the ascorbate oxidase activity from stem-end pericarp tissue of a BER-affected fruit is similar to the stem-end and blossom-end of healthy fruit. In our pericarp disc system, ascorbate oxidase activity was significantly correlated with objective measures of tissue darkening , suggesting that similar antioxidant depletion processes occur during symptom development in discs as in whole fruit.Peroxidase activity was chosen as a second indicator of enzymatic similarities between symptom development in discs and BER development on the plant. Peroxidase activity measured using an aromatic electron donor was shown to be greatly increased in BER fruit compared to healthy fruit. This trend has been linked to increased lignification, and peroxidase trends presented by Reitz and Mitcham are similar to those found for ascorbate oxidase activity in Additional file 3: Figure S2. In our disc system, peroxidase activity was significantly correlated to measures of tissue darkening , suggesting a similar trend to that of increased peroxidase activity in BER affected whole fruit on the plant as compared to healthy fruit.Regulation of respiration is vital to plant health, with increased respiration indicating an increase in energy consumption and possibly stress. Results presented here indicate symptom development is associated with an increase in respiration rate. Furthermore, the correlation between respiration on day 1 and color measurement on day 2 indicates this increase in respiration rate occurs prior to visual symptoms. Blossom-end disc respiration decreased to near the level of the stem-end discs on day 3, possibly due to cell death or exhaustion of the available chemical energy pool. This also indicates that processes associated with blossom-end rot are likely active prior to visible symptom development.Calcium deficiency in soil and fruit tissue has long been associated with BER incidence. However, abiotic stress can also increase BER incidence, bringing into question the direct relationship between BER occurrence and calcium deficiency. We applied calcium chloride and ascorbic acid to disc tissues to test the direct effect of increased calcium and antioxidant potential onBER development. Both treatments eliminated symptom development as evaluated visually and by colorimeter. Calcium localization within the cell is a key factor in BER incidence. De Freitas et al. directly studied the effect of calcium localization at the cellular level by increasing vacuolar calcium through increased expression of the sCAX1 gene. Increased vacuolar calcium was associated with decreased apoplastic calcium and increased BER incidence. Calcium applied to the pericarp disc systems would likely diffuse into the apoplast, testing the opposite localization state compared to that of De Freitas et al.. As expected, the opposite effect was observed when calcium was applied. Correlation of BER symptom development with increased ROS accumulation and depleted antioxidant activity has been well established in the literature.

November 15, 2023

The differences in CEC metabolism imposed by treatments or species warrant further investigation

The results presented in this dissertation suggest the highly chemical-, species-, and research technique- specific nature of the environmental fate of CECs. For example, cell cultures often form amino acid conjugates while whole plants form sugar conjugates during xenobiotic metabolism. Additionally, more toxicological data are needed on the effects of these and other compounds in terrestrial invertebrates, especially for those of agricultural importance. From the research conducted in this dissertation, future research should focus on the impacts of exposure and the potential for transformation of CECs under different conditions and in multiple species. Future studies should place emphasis on experimentation using bio-solids and TWW with inherent compounds and field conditions to improve environmental relevance. Future risk assessments should be conducted by taking into account the formation of biologically active and conjugated metabolites, and with regard to the potential toxicity of CECs in non-target terrestrial organisms. During the past 3–4 decades, parallel expansions of populations of non-indigenous rhizomatous grasses have occurred in aquatic and estuarine habitats around the nation. Among these expansions are Spartina alterniflora invasions in the salt marshes of the Pacific Northwest , take-over of large sections of the riparian ecosystems in Southern California by Arundo donax and Phragmites australis invasions in the upper regions of salt marshes in the mid-Atlantic states . The east coast salt marsh grass Spartina alterniflora has been invading west coast salt marshes from San Francisco Bay through Washington since the early 1970’s . Although S. alterniflora can produce seeds that are spread by water movement, it spreads mainly through the expansion of its underground rhizomes. In Washington salt marshes, S. alterniflora is large compared to other salt marsh species,blueberry pot size and it is altering ecosystem structure by affecting benthic structure and species diversity .

Likewise, in San Francisco Bay, S. alterniflora displaces the native wetland plants, as well as eelgrasses and algae. In the mid-Atlantic region, Phragmites australis has invaded many wetlands , and replaced much of the upper marsh vegetation, that was characterized by Spartina patens and Distichlis spicata. The 2–3 m tall stems die back at the end of the growing season, but the densely grown shoots remain in place, affecting sedimentation patterns, surrounding less tall vegetation, and use of the marsh by mammals and birds. The rhizomatous grass Arundo donax that in the riparian ecosystems of Southern California has expanded into large, self-sustaining populations, has become an ecological and economical pest. The populations expand through the distribution of vegetative propagules, in the form of stem and rhizome fragments by the rivers. Currently the expansions of rhizomatous grasses like these are combated with mechanical and/or chemical methods. Both these approaches have pros and cons, and their application is affected by the local environmental conditions, funding, and available manpower .The overall goal of this project was to increase the knowledge of the ecophysiology of the internal processes targeted by, or the ecological processes resulting from control efforts, and to facilitate conveyance of this type of information and knowledge to agencies and individuals engaged in control effort of rhizomatous grasses in aquatic and estuarine habitats. The physiological process that we will focus on is allocation of photosynthates to different parts of the plant and the role of internal nitrogen in this process, in order to determine the most effective time for herbicide application.In the hydroponic culture described earlier, the S. alterniflora seedlings that were precultured in deionized water showed an initially slow, but increasing growth, until the growth is reduced near the end of the experiment at week 12 . Specifically, the growth of leaves and stems stopped , as the plants exhaust the N supply from their nutrient solution , and the leaves’ internal N decreases down to their CNC . Before the leaves reached their CNC at the end of week 11, rhizome biomass showed a slow increase to 1.93 + 0.257 g. After the leaves reached their CNC in the last five weeks of the experiment, approximately 6.11 g was added to the rhizome biomass.

While at CNC, internal leaf N content was seen to increase above CNC for a short period, after nutrient additions to the culture solution. In this period, the leaves showed slight biomass increase as well . As the rhizomes grow, new roots and tillers develop at many of their internodes, and the biomass of these tissues show a significant increase , that is related to the increase of S. alterniflora rhizome length.The leaves that were collected from tall and short S. alterniflora in the DE salt marsh, showed differences in the seasonal pattern of the internal N content . At the start of the growing season in March, the leaf N/C ratio in the tall S. alterniflora is high at almost 0.06 g N/gC. In the short S, alterniflora the N/C was lower than both the tall S. alterniflora from the same marsh, and the S. alterniflora in the hydroponic greenhouse experiment early in their growing season . The internal N/C ratio in the leaves of the short S. alterniflora does not change much during the entire growing. In the second half of the growing season, the internal leaf N/C ratios in the tall S, alterniflora leaves decreases and becomes indistinguishable from the N/C ratio in the short S. alterniflora’s leaves.The difference between the growth patterns of the two groups was most pronounced in the growth of the green leaves and the stems. These variables show a reduction in the nitrogen-deprived plants when compared to the plants that continue to receive nitrogen, especially the leaves . In addition to the seemingly smaller amount of above ground plant material, the leaves of the nitrogen-deprived plants were a much lighter color green, and leaf senescence was more common for these plants . As a result of this combination of responses, the nitrogen-deprived plants appeared much smaller than those that continued to receive nitrogen. At the time of reduced leaf growth by the no-nitrogen plants, the internal N content in the nitrogen-deprived plants dropped significantly below the N content in the leaves of the N-supplied plants . This was observed through both the carbon-based and the dry-weight based determination of the tissue N content. The lowest mean N/C ratio was 0.038 + 0.001, and % N dropped below 2%, to 1.69 + 0.052%, at the time that the N content in the leaves of the control plants was lowest as well, with N/C = 0.077 + 0.004 and N = 3.446 + 0.167%.During nitrogen deprivation the growth of mature green leaves was limited or nonexistent, due to lack of mobile nitrogen. Both the function and growth of leaf tissues have a high requirement for nitrogen.

Each functional leaf cell will need to contain a minimum amount of nitrogen for both photosynthetic pigments and enzymes such as chlorophyll and Rubisco, and a full complement of DNA and nucleic acids for RNA production. Once the tissue nitrogen has been diluted to the lowest functional level, also referred to as the Critical Nitrogen Content , each cell will only contain this minimum amount of cellular nitrogen allowing it to function at maintenance level. Therefore these cells will not contain enough nitrogen to produce another complement of DNA and enzymes,blueberry plant size preventing them from dividing and the tissue to grow. During internal nitrogen limitation when leaf biomass did not increase anymore, photosynthesis was not reduced in Ipomoea batatas . Photosynthesis continued after the leaves have reached their CNC and the external nitrogen was depleted. The carbohydrates produced cannot be stored in the leaf tissue since further input of carbon compounds into leaf cells would lower the nitrogen to carbon ratio below their CNC, thus interfering with cell function. Instead of having been incorporated into the leaves, these carbohydrates were translocated to the sinks that are the rhizomes, roots, and for S. alterniflora, the rhizome tip tillers. This S. alterniflora study has shown that growth of that species’ vegetative reproductive structures, the rhizomes, occurs after the internal nitrogen content in the leaves is too low to allow for growth of the leaves. The manufacturers of systemic herbicides advise application of their product when there is substantial translocation to the below ground tissues of the plant. For the control of S. alterniflora to be effective, a systemic herbicide has to be carried in the phloem stream to the below ground permanent structures for winter survival and spring regrowth, the rhizomes and the associated rhizome tip tiller. Most rhizome growth and nearly all growth of rhizome tip tillers occur when the leaf N content has reached its CNC. It is obvious therefore that most photosynthate transport and incorporation in the rhizomes and rhizome tip tillers occurs at the time of low leaf N/C ratios, and not before.

We can expect substantial ‘delivery’ of the active ingredient in systemic herbicides which are carried in the phloem, such as glyphosate, to the target tissues would occur at the time of low leaf N/C. Therefore, it may be beneficial to take leaf N/C ratios into consideration when determining the timing of systemic herbicide applications. The field sampling in this study showed that the leaf N/C ratio of short S. alterniflora that grow away from the creek banks is almost always at its CNC level, while the leaf N/C ratio of the taller plants that grow on the creek banks showed a high level at the beginning of the growing season, and a decrease with time not unlike that of the plants in our greenhouse study. This indicates that our experimental conditions were a reasonable mimic of creek bank salt marsh conditions. Additionally, it indicates that N availability in the fine grained, and anoxic marsh sediment away from the creek banks is significantly different from that in more coarse grained creek bank sediments, through which, rather than over which, the flooding water moves during tidal movements. The low oxygen availability in this marsh sediment may interfere with the uptake of the nutrients, or the nitrogen content of this soil may be lower since exchange between the interstitial soil water and the periodically overlaying nutrient rich sea/marsh water will be limited due to the dense and fine-grained nature of the soil. In a series of studies by our laboratory that observed the role of leaf N content in the allocation of growth on multiple species, the P. australis study was the first in which we controlled the N concentration in the hydroponic nutrient solution. Continuous high concentrations were maintained for all plants until the 11th week of the experiment, at which time the N was removed from the nutrient solution for half of the remaining plants. The growth of the plants in both the no-nitrogen and the nitrogen supplied groups showed the importance of external and internal N on the allocation of growth in P. australis plants. It was interesting that even after the removal of the external N, the plants increased their living biomass by 39 g dry weight, which was almost as much as the 49 g biomass increase of the plants supplied with N. The biomass increase of the plants without external N was most likely supported by the pool of internal N in the plant. At the time the external N supply was removed, the N content in the plants was above their CNC. The critical nitrogen content of a tissue is defined as the lowest amount of nitrogen in tissues that will allow for growth the growth of that tissue. Total plant biomass increased after the removal of the external N, which was evidence that photosynthesis must have continued. As more carbohydrates are produced and incorporated into the plant without an external supply of new nitrogen, the internal N/C ratio in the tissues will decrease. As described earlier, among the different tissues, leaves have the highest CNC, and will therefore reach this CNC earlier than tissues with lower CNC values. When the leaves reached their CNC, they could no longer incorporate more C into their own tissues, since this would reduce their N/C below the CNC and interfere with their function . At this point two scenarios are possible; one is that photosynthesis could shut down, and the other is that all the carbohydrates produced in the leaves could be transported to other tissues of the plant.

November 14, 2023

Polyparabens reportedly inhibited root growth in onion bulbs under hydroponic conditions

Carbamazepine exposure has been seen to exhibit mycotoxicity to carrot mycorrhizal endpoints by decreasing the production of fungal spores . Similarly, carbamazepine induced leaf necrosis, altered plant hormones and macro-nutrient concentrations, and reduced root growth at plant tissue concentrations of 1 to 4 mg kg-1 in zucchini cultivated in soil spiked with chemical at 0.1 – 20 mg kg-1 . Information on the toxicity of benzodiazepines and fluoxetine in terrestrial plants is still limited; however, toxicity has been reported in aquatic plantsfor these compounds, indicating that toxicity may also occur after exposure in terrestrial plants .Antimicrobials and preservatives are often added to personal care products to increase shelf life. They pass from the human body, largely unchanged, and ultimately end up in TWW, bio-solids, and sewage sludge. . Antimicrobials and preservatives have been detected in agricultural soils after irrigation with TWW and/or the application of bio-solids, and can be taken up by plants . Two antimicrobials, triclosan and triclocarban, have attracted more attention because of their potential for endocrine disruption and phytotoxicity . For example, triclosan significantly inhibited plant growth in cucumber and rice seedlings with EC50 of 108 mg kg-1 and 57 mg kg-1 , respectively . Lettuce shoot mass also decreased in a dose-dependent manner after cultivation in soil amended with triclocarban-spiked bio-solids . On the other hand, growth of radish, carrot, soybean, spring wheat, and corn plants grown in soils amended with bio-solids containing environmentally relevant concentrations of triclosan and triclocarban, improved compared to un-amended soils; likely due to the positive impacts of bio-solids addition . Thus, plant species, concentrations, and growth media can significantly affect phytotoxicity of these CECs. Similarly to antimicrobials, parabens have also garnered recent attention due to their potential for endocrine disruption and phytotoxicity . Methyl paraben, the most commonly detected paraben,raspberries in pots has been shown to inhibit seed germination in rice and mung bean in aqueous solutions at respective concentrations of ≥100 mg kg-1 and ≥ 200 mg kg-1 . Methyl paraben decreased shoot growth and biomass in both rice and mung beans at a concentration of ≥ 200 mg kg-1 in soil .

Studies exploring the phytotoxicity of individual pharmaceuticals or classes of pharmaceuticals are useful to highlight high-risk compounds and/or the potential mechanism of toxicity. CECs are, however, often introduced into the environment in complex mixtures and these mixtures can affect the uptake and translocation of individual compounds . Some studies report positive effects on plants exposed to CEC mixtures under environmentally relevant conditions. For instance, TWW irrigation increased tomato and lettuce yield compared to freshwater irrigation . Exposure of lettuce seedlings to a mixture of 11 CECs significantly altered plant metabolic pathways, including the citric acid cycle and pentose phosphate pathway, and decreased chlorophyll content in a dose-dependent manner . Also, exposure to 18 CECs at concentrations ranging from 5 to 50 µg L,-1 induced oxidative stress in cucumber seedlings and caused upregulation of enzymes associated with detoxification reactions . Literature on the toxicity of a number significant CECs to terrestrial plants is still very limited, and many of the studies have utilized concentrations that are orders of magnitude higher than those seen in the environment. Studies on the toxicity of mixtures in terrestrial plants are also limited, but warrant attention as several studies have indicated that mixtures can induce effects not observed from individual compounds . The ability of plants to detoxify these compounds through metabolism also merit further research. Overall, more research is needed on the toxicity of a wider range of CECs in plants under environmentally relevant conditions to more accurately assess the impacts of CECs in the agro-environment. The potential for exposure to, and toxicity of, CECs has been investigated in several aquatic invertebrate species. Toxicity end-points such as endocrine disruption, changes in growth, time to development, and mortality rates have been considered in these studies . Studies addressing the effects of CECs on terrestrial invertebrates are, however, few. Of the published studies on terrestrial invertebrates, the earthworm Eisenia fetida has been examined mainly due to their increased susceptibility andecological importance . Literature pertaining to toxicities of various classes of CECs to terrestrial invertebrates is discussed below. Like in terrestrial plants, antibiotics can also induce toxicity in terrestrial invertebrates. Exposure to environmentally relevant concentrations of antibiotics caused mortality to earthworms and/or induced oxidative stress and genotoxicity in E. fetida. For instance, high concentrations of tetracycline and chlortetracycline inhibited antioxidant enzymes superoxide dismutase and catalase while these enzymes were stimulated at lower doses , and DNA damage was induced along a dose-dependent curve . Also, chlortetracycline can reduced juvenile earthworm and cocoon counts in E. fetida .

Environmentally relevant concentrations of three antibiotics, lincomycin, ciprofloxacin, and oxytetracycline increased mortality and development time in cabbage loopers when reared on an artificial diet and treated tomato plants . Further, the three antibiotics altered the microbiome inside cabbage loopers and mosquitos but did not impact development time of mosquitoes . However, antibiotic exposure did not induce toxicity in aphids reared on bell peppers . Antibiotic toxicity in terrestrial invertebrates, therefore, appears to depends upon the specific antibiotics, concentrations, bioavailability, invertebrate species, and environmental conditions.Exposure to NSAIDs caused acute and sub-acute adverse effects in terrestrial invertebrates, including earthworms . Pino et al. assessed lethality of E. fetida cultivated in artificial soil as a result of exposure to 18 pharmaceuticals. Ibuprofen had the lowest LC50 at 64.8 mg kg-1 followed by diclofenac at 90.5 mg kg-1 . Exposure to diclofenac resulted in a dose-dependent decrease in survival and reproduction of Folsomia candida in spiked soils . However, it should be noted that these LC50 values were much higher than what may be expected in the real environment. At sub-acute concentrations , diclofenac induced significant genotoxicity in Folsomia candida, including induction of the up-regulation of transcriptional processes and genes associated with the immune response . Acetaminophen increased E. fetida mortality along both a dose-dependent curve and over time [7-28 d ]. In the mosquito species Culex quinquefasciatus, exposure to water contaminated with an environmentally relevant concentration of acetaminophen resulted in increased susceptibility to Bacillus thuringien israelensis and increased larval development time . Acetaminophen at environmentally relevant concentrations also significantly increased days to adulthood in cabbage loopers reared on an artificial diet. However, a similar effect was not observed when cabbage loopers were reared on acetaminophen-treated tomato plants . Similarly, the development time for aphids reared on acetaminophen treated bell pepper was not affected by acetaminophen . Therefore, like for other CECs, effeccts of NSAIDs on terrestrial invertebrates are species, compound, and environment specific.

Many antimicrobials and preservatives, including the common environmental contaminants triclocarban, triclosan, and parabens are amongst the most frequently detected in TWW and bio-solids . Partitioning of these CECs into bio-solids suggests that soil-dwelling organisms are at greater risks of exposure as they preferentially consume organic matter rich soils and bio-solids . Triclocarban, triclosan, and methyl-triclosan have been detected in the tissues of earthworms collected from field sites that were amended with bio-solids 4 years prior to the worm collection . After 28-d exposure to triclosan at ≥50 mg kg-1 in soil E. fetida had significantly increased SOD and CAT activities and increased concentrations of malondialdehyde , a chemical indicative of lipid peroxidation and DNA damage in E. fetida . Lin et al. reported negative impacts of triclosan exposure on E. fetida reproduction including decreases in the number of cocoons and juveniles. Triclosan also decreased the biomass, shell diameter,blueberries in containers growing and food intake in a terrestrial snail at concentrations ≥ 40 mg kg-1 . Further, triclosan exposure increased CAT and SOD activities and MDA concentration in A. fulica in a dose-dependent manner . However, no adverse effects were observed in E. fetida cultivated in triclosan-amended bio-solids at environmentally relevant concentrations . Triclocarban is more persistent in the environment than triclosan and is known to bio-accumulate in earthworm tissues . However, information on its toxicity to terrestrial invertebrates remains limited. For example, in Synder et al. exposure to triclocarban at concentrations ≥ 77 mg kg-1 for 2-4 weeks resulted in a trend towards increased mortality; however, the variations in data were too high to discern any statistically significant trend. Exposure ≥ 400 mg kg-1 to methyl paraben in soil resulted in increased abnormalities in earthworms where a normal survival-EC50 value of 397 mg kg-1 was estimated . An acute exposure to methyl paraben in soil at ≥ 60 mg kg-1 increased F. candida mortality and chronic exposure at concentrations ≥150 mg kg-1 decreased the reproductive rate . However, methyl paraben is often detected at concentrations ranging from 15.9 – 203.0 µg kg-1 in sewage sludge, levels that are well below the concentrations where toxicity was observed .The studies highlighted above suggest that CECs are ubiquitous in the environment and that exposure, even at environmentally relevant concentrations, these contaminants may be hazardous for terrestrial organisms. However, studies also suggest that these organisms can metabolize, transform and detoxify these CECs. The interplay between the toxicological effects of CEC exposure and an organism’s ability to take up and metabolize these contaminant is poorly understood and serves as significant knowledge gaps in understanding the fate and risks of CECs in terrestrial environments. These gaps must be addressed to gain better risk assessments of CECs during the use of bio-solids and treated wastewater in the agro-environment.

To address these gaps, we carried out a series of experiments utilizing plant cell cultures, hydroponic cultivations, earthworm incubations, high-resolution mass spectrometry, 14C-tracing, and enzyme assays to systematically evaluate the fate, metabolism, and biological effects of sulfamethoxazole, diazepam, naproxen, and methyl paraben and their major metabolites in terrestrial organisms under laboratory conditions. The four CECs were selected based on their detection in TWW and bio-solids, their range of physicochemical properties and uses, and the paucity of information about their fate and impacts in the literature . The study systems included Arabidopsis thaliana cells cultures, radishes, cucumbers, and E. fetida. Organisms were selected due to their extensive use in the literature, commercial availability, and worldwide agricultural relevance. Over the past two decades, pharmaceuticals and personal care products have emerged as contaminants of environmental concern due to their extensive use and continuous emission into the environment . PPCPs are released into the environment primarily through the disposal of treated wastewater and bio-solids from wastewater treatment plants . As climate change and population growth places an increasing stress on freshwater resources, especially in arid and semi-arid regions, communities have turned to utilizing municipal treated water for agricultural irrigation, which may result in soil contamination by PPCPs . Furthermore, the heavy use of some pharmaceuticals, particularly antibiotics, for disease control and growth promotion in intensive animal farming also contributes to contamination of agricultural fields when animal wastes are used for fertilization . The presence of PPCPs in irrigation water and soil can lead to contamination of food crops if plants can substantially accumulate these compounds. Various studies over the last decade have sought to quantify plant uptake of PPCPs, and in general, only low levels of PPCPs have been found in edible tissues . The majority of studies to date have only targeted the parent form of PPCPs for analysis. However, plants have a cascade of enzymes that may extensively transform xenobiotics such as PPCPs after uptake . Recently several published studies have explored the metabolism of pharmaceuticals in plants . Therefore, consideration of metabolism and biologically active metabolites is much needed for a better understanding of the fate and risks of PPCPs in the soil-plant system. Higher plants have many detoxification enzymes similar to those in animals. These enzymes function in plants as a ‘green liver’ . In general, metabolism of xenobiotics includes three phases. Phase I involves modification reactions such as oxidation, hydrolysis, and dealkylation reactions introducing reactive sites to the molecule. Phase II is characterized by conjugation with large polar bio-molecules, such as sugars and amino acids, to further increase the polarity of the xenobiotic. Phase III is typified by sequestration, resulting in the formation of bound residues . As shown for many xenobiotics in mammals and plants metabolites from phases I and II often retain biological activity , and therefore should not be discounted. In this study, sulfamethoxazole was selected as the compound of interest because of its prevalence in WWTP effluents and increasing concerns over the propagation of antibiotic resistance .

November 13, 2023

It is our hope that this discussion serves as a figurative road map for drawing your own conclusions

Non-human actants such as soil, water, and organic certification, are not included in this diagram. Further, it only accounts for actors that were encountered during fieldwork and is not meant to be exhaustive. Instead, it hopes to provide a snapshot of the ever-changing networks of actors and actants that were involved during the research period . The practice of mapping out the flows allowed us to identify key nodes of power among the urban agriculture networks in San Diego County, which are indicated on the diagram by use of a darker hue of the parent shade used for each network. For example, Leichtag Foundation is a key node of power in the Coastal Roots Farm actor-network. These actors marshall considerable power in comparison to the other actors enrolled in the networks, whether through the possession of crucial resources such as land and capital, political power, and/or consensus-building. In what follows, we discuss the discoveries we made through examining the vignettes and the network relationships. This discussion provides the results we drew from analyzing the vignettes and the network diagram.The microgeographies of these local commodity circuits had considerable influence on the discursive and material relations present at these sites. Narratives around place drove and legitimatized sites’ growing practices and their approaches to justice, whether based on donations or democratic participation. Further, the characteristics of place drove production, distribution, and consumption practices, which had important implications for justice. Every place in this research had different needs and populations, which drove their place-specific emphases and practices. For example, a mission focused on food sovereignty might be inappropriate in an affluent,plastic plants pots primarily white community like Encinitas . However, this mission is apt in a low-income, minority neighborhood like Southeastern San Diego, which has experienced considerable disinvestment and structural oppression.

These missions at our sites were fitting and reflected what was going on in those places and within their communities. This drove not only production practices, but also distribution and consumption – the lack of substantial need in Encinitas led to distribution in “less fortunate” communities outside of the neighborhood in order to fully realize their mission. This distribution pattern resulted in a more geographically dispersed network that engaged multiple communities with disparate experiences in a single commodity circuit. The characteristics of place and the narratives around production and distribution drove the actors and actants that enrolled in these networks. The most successful and stable networks in our cases, Solutions Farms and Coastal Roots Farms, successfully enrolled actors with substantial capital resources such as Leichtag Foundation and Alliance Healthcare. Indeed, Daftary-Steel, Herrera, and Porter convincingly argue that urban agriculture projects can only truly sustain themselves and produce public goods like nutritious food, education, and job readiness with external investment in the absence of “major shifts in our national wage structure” . Three factors, we argue, contribute to this successful enrolment of funders: proximity, measurable outcomes, and narrative content. Powerful actors, especially those with sustaining capital resources, are often not located in areas of the most need like Southeastern San Diego and therefore may have few, if any, ties to the neighborhood. Measurable outcomes also play a role in enrolling actants with capital resources – as we illustrated in Chapter 3, sites that practice distributive justice, which produces more readily quantifiable outcomes, attract more funding because they can illustrate the efficacy of investment. Although Mt. Hope Community Garden is still successful at enrolling philanthropic foundations into its network, investments are relatively small because of the difficulty of quantifying outcomes like participation and social cohesion. The final aspect is the content of narratives associated with each urban agriculture site, which are part of what makes them unique places. These narratives are both produced by the actor-networks and at the same time powerful actants that shape these networks – an important contribution of Actor-Network Theory. Mainstream neoliberal and reformist narratives that focus on social enterprising and food security may be more successful at attracting funding, as opposed to narratives that focus on food sovereignty. Indeed, funders are often less connected to the histories of structural oppression that drive grassroots urban agriculture projects like Mt. Hope Community Garden. This trend results in a situation in which the most disenfranchised find it difficult to enroll actors with crucial financial resources, giving support to the hypothesis that those with significant resources are more successful at attracting funding .

It also reinforces race- and class-based inequalities because projects run by disenfranchised groups, which more often have progressive or radical agendas , struggle to obtain the support necessary to sustain themselves financially. We saw this in our analysis of Mt. Hope Community Garden. The food justice narratives that surround the garden and its parent organization do successfully enroll actors with knowledge and skills to support its activities. However, the garden received considerably less funding from its network members, leaving it at the helm of the City of San Diego and its decision to sell their property. Actants like soil, water, technology, produce, and the narratives attached to them also drive action and enroll actors into the networks supporting urban agriculture commodity circuits. For instance, the produce grown at the sites determines the extent to which the organizations can generate revenue, feed people, and drive their mission. The use of soil and narratives around its ability to foster community are particularly salient at sites like Coastal Roots Farm. Technology and narratives around innovation similarly enroll actors that value modernization and novelty – technology played an important role in Solutions Farms enrollment of Alliance Healthcare and its $1 million-dollar Innovation grant. These actants, as Bosco describes them, allow our case sites to “become what they are” and explain why some networks and the justice activities embedded within them are more sustainable than others . Tracing the many connections and relations across our commodity circuits illustrates that the story is more complicated than the presence or absence of soil. Watercress is a semi-aquatic plant that grows in f lowing shallow freshwater and is found across Europe, Asia, the Americas, the Caribbean, New Zealand and Australia. Watercress is placed within the Brassicaceae family together with several other important food crops including broccoli, kale, cabbage, and mustard. A significant amount of commercial aquatic watercress cultivation is centred in a few locations including Florida in the USA, southern Spain and Portugal, France and the south of England, with 90% of production occurring in Dorset, Hampshire and Wiltshire. These chalky areas provide nutrient-rich spring water and boreholes that directly supply the watercress beds. Phosphate-rich fertiliser is used to boost crop yield; however,blueberry pot this presents a major challenge in watercress production since it results in direct leakage of phosphate into the waterways which have high conservation value.

Excess phosphate results in eutrophication of aquatic ecosystems, a process where nutrient enrichment of water sources results in excessive algal and plant growth, and subsequent disruption of ecosystem community dynamic. Approximately 90% of watercress farms in the UK are on, or upstream of, a Site of Special Scientific Interest , increasing the pressure to minimise phosphate release.Phosphate is vital for plant survival; it forms the phosphodiester bonds that link nucleotides in nucleic acids and is critical for the structure of proteins and carbohydrate polymers, for powering cells through the release of phosphate from ATP and for regulating several metabolic pathways Symptoms of P deficiency are retarded growth, increased root:shoot biomass, decreased leaf area and often dark green or purplered colouration in severely deficient plants due to anthocyanin production. Ninety percent of the global demand for phosphorus is used for food production, however, rock phosphate is a limited resource with estimates that reserves could be exhausted in the next 50–100 years . In addition, most of the remaining rock phosphate reserves areunder the control of only a few countries, with Morocco and the Western Sahara holding over 70% of the total reserves, making it sensitive to political instability. This, combined with increasing costs of extraction and issues of eutrophication,make reducing fertiliser use an important global driver. The high reactivity and low solubility of phosphates make them commonly the growth-limiting nutrient for plants. Accounting for fertiliser application, approximately 30% of global cropland area exhibits soil P deficits although global P imbalances in water sources have not been investigated to any significant extent.Like soil, P in aquatic systems is also divided into different fractions based on solubility and reactivity in aquatic systems, with dissolved orthophosphate the most bio-available. P in water adsorbs to oxides and tightly binds with carbonates in the same manner as when in soil. However, the P inputs to natural water systems and the interaction with P in bed sediments is altered. This creates a dynamic source of phosphorus that transfers between particulate and dissolved forms, between bed sediments and the water column, and between dead and living material . In a watercress bed, the sediment is shallow gravel and thus P uptake from water likely represents the major P source. This is ref lected in a study by Cumbus and Robinson who found that a greater proportion of P was absorbed by the adventitious roots of watercress , compared to basal roots. However, some organic detritus held within the sediment should still be considered. Phosphate dynamics in hydroponic agricultural systems such as watercress beds have not been studied, representing a knowledge gap, but P is likely uniformly distributed due to f lowing water and regular maintenance of P concentrations. Since P retention in sediments is high, P delivery into freshwater systems is largely governed by release from point sources such as sewage treatment works , leaking septic tanks, and from excess fertiliser application. Globally, domestic sources contribute 54% to total P inputs into freshwater systems, 38% from agriculture and 8% from industry. Although substantial steps towards P reduction in fresh waters have been made over the last 50 years there is still much to be done, with only 40% of European surface waters currently in good ecological status.

Eutrophication of watercourses is also prevalent across the UK: in the most recent analysis, 55% of river water bodies in England failed to meet the revised P standards for good ecological status. Eutrophication is both an economic as well as environmental issue. In the US, the economic damage of eutrophication equates to $2.2 billion annually, due to losses in recreational water use, waterfront real estate, recovery of endangered species and drinking water. Naturally, phosphate levels in chalk aquifers are less than 20 μg/l, however, inputs of phosphate rapidly increase these concentrations above P targets downstream of watercress farms. In the river Itchen where several watercress farms are located, total SRP load comes predominantly from sewage treatment works but watercress beds can be responsible for up to 62% of the total reactive phosphate in some chalk streams, suggesting room for improvement in P management. Casey and Smith found watercress beds increased mean P concentrations which may cause undesirable growth of algae and disruption of community dynamics. One important strategy to tackle this problem of eutrophication is through plant breeding. By breeding watercress varieties with improved phosphorus use efficiency , the impact of watercress farming on eutrophication could be minimised. To date, no breeding for nutrient use has been conducted in watercress even though P release represents a clear issue in watercress production.Phosphate use efficiency is defined as the capacity for biomass production using the P absorbed . Here PUE is used as a broader term that also encompasses phosphate acquisition efficiency, defined as the ability to take up P, as has been used in several studies. Plant traits underpinning PUE can be observed at the macroscopic, microscopic, and molecular levels and we consider their relevance to future breeding for enhanced PUE. To date, knowledge on P acquisition by aquatic plants only covers the effectiveness of plants for phytoremediation , rather than breeding for PUE in aquatic crops such as water chestnut , water spinach , lotus and watercress. Present information does not cover morphological or genetic components to improve PUE in aquatic species, and with new plant species emerging as suggested model organisms, watercress is offered as a model crop for aquatic systems.

November 10, 2023

The clearest distinction in this figure appeared to be whether the growing sites are for-profit or nonprofit

For instance, 75 percent of the articles returned in our Web of Science search were published after 2009 and 18 percent were published in 2017-18. A more recent search of these terms in April of 2018 returns 1622 records revealing a continued growth in literature on urban agriculture. Of these records, journal articles dominate . Other records include book reviews, article reviews, proceedings papers, and meeting abstracts. The main contributing journals included Land Use Policy , Landscape & Urban Planning , Agriculture & Human Values , Sustainability , and Local Environment ; however, the sources were quite diverse. Each record represents a single document and together they form the corpus used to build the reference topic model. Prior to processing, we removed any stop words, punctuation, and URLs. We performed LDA topic modelling using the MALLET program . We produced various topic models using three granularities , and used the models with the greatest log likelihood . We then examined their topic composition and removed topics dominated by non-meaning-bearing terms including time and location indicators and general publication information . These topics were identified using the alpha hyperparameter, where relatively high values indicated that the topic was common throughout the corpus and therefore not meaningful for examining differences within our sample. After these adjustments, we determined that the 25-topic model was ideal for analysis using personal expert knowledge on urban agriculture literature. The reference topic model was created in order to perform inference on content produced by urban agriculture growing sites and regional organizations in San Diego County – in other words, to interpret the content produced by the key actors identified above . We created a corpus including all textual content from the websites of agencies in our sample,plant pot with drainage with content from each of the 48 observations contained in a single document in the corpus.

Textual content included any written descriptions on the website including history, mission and vision statements, program descriptions, excluding locations, contact, and event info. For growing sites associated with larger organizations or institutions, we also collected basic descriptive content from the parent website. By applying the reference model to all the documents, each document is characterized in terms of topic composition, allowing comparisons among documents . The output of the inferencing process is a document-topic distribution matrix, from which we computed a matrix of cosine similarities among documents. In order to visualize these similarities, we used a dimensionality reduction technique known as multidimensional scaling . In the resulting output, each document is described as a 2-D point in Cartesian coordinates, where proximity relates to similarity. The resulting discursive map displayed the inferenced website corpus, with each point representing a single growing site or organization. The location of each point relates to its particular topic composition. The distance between points is indicative of their discursive similarity – the closer two points are in the discursive map, the more similar their topic composition; the farther apart, the more dissimilar. We investigated this map, but also created a series of variations, altering the symbology of the discursive map to reflect particular features of the sites. This allowed us to examine the connections between characteristics like growing methods and topic composition. We were also interested in discovering clusters among the data points, and so we utilized k-means clustering to identify meaningful groups in our data . K-means is a heuristic algorithm that attempts to partition aninput dataset into k groups, allowing researchers to explore clusters within a dataset. Our data seemed to occupy primarily three quadrants in the discursive map, and so we chose to identify three classes. This algorithm was run for 1,000 iterations and the results with the lowest sum of squared errors – a metric that explains the difference between each observation and its corresponding k-means centroid – were chosen as representative. This analysis complemented our visual analysis of symbology patterns. The growing methods symbology illustrating the practices used by growing sites revealed a distinct, but blurry pattern between motivation and practice.

When analyzing the map using this symbology, a general pattern emerged in which technologically-advanced sites tended to group in the top-left quadrant of the map with two outliers: Go Green Agriculture and Archi’s Acres. The absence of innovation in these outliers’ top-three loadings suggested that other topics precede technology in how these growing sites describe themselves despite their use of advanced technologies. Generally, soil-based sites occupied the right side of the discursive map; however, soil-based farms such as Suzie’s Farm, Good Taste Farm, and Point Loma Farms were grouped in with the soilless sites. Growing site and organization descriptions of their processes did drive their location on the discursive map. For instance, the soilless sites often described the inventive and underrepresented practices they use to grow produce in the urban environment. However, the content did not end there. Other topics like social movements, climate change, and food access were also present among these sites. We saw a similar trend with sites using a community gardening model. When we explored the entire topic loadings of growing sites and organizations, ignoring practice-based topics like innovation and community gardening topics, we saw that the clusters have far more similarities than differences. Interestingly, these soilless sites are typically affiliated with businesses as opposed to nonprofits which dominate the right side of the map, where most soil-based sites are located . Indeed, we expected that business and nonprofit website content would vary and these results provide evidence to that effect. San Diego Food System Alliance, the leading regional nonprofit organization, is located in the center of the map. This location is not surprising in the context of neoliberal governance in which cities and regional organizations are more focused on building consensus and supporting apolitical agendas, rather than taking on political causes .The affiliation symbology illustrating the relationship between institutional affiliation and content was less coherent than the other symbologies displayed in previous figures, but still offered important insights. Growing sites were affiliated with a variety of institutions including schools, churches, organizations hosting training and educational programs, and for-profit businesses.

Education sites were located throughout the map suggesting that training and skill-building are not major dividing factors in discourse. In other words, many different types of organizations claim to focus on education. However, church, community, and school gardens tended to concentrate in the top-right section of the map, which is typically associated with soil-based community gardens. However, it cannot be assumed that the for-profit sites lack social mission. For example, Archi’s Acres, a for-profit hydroponic farm in Escondido, includes a social enterprise function focusing on training veterans in hydroponic farming. Sundial Farms, a veteran- and immigrant-owned, hydroponic farm in the Innovation cluster, is a direct result of this program. This social function features prominently in its website content: “At Archi’s, we believe a key aspect of successful business is how it meets its responsibility to the community in which it operates and the customers which make up its marketplace. We do this by integrating into our business model an opportunity to support others including our military service members and veterans.” This broader social mission may explain its topic loadings and the absence of innovation as a primary topic. The overall uniqueness of this growing site may explain its peripheral location in the discursive map. Solutions Farms, an aquaponic operation associated with Solutions for Change,growing blueberries in pots was the only nonprofit located in the for-profit dominated section of the map. The organization aims to alleviate family homelessness in the county through skill development, including training in aquaponic farming. However, innovation is the primary topic in their content, influencing their location among other sites whose discourse is focused on innovation.Multivariate clustering was performed on the discursive map to identify clusters in the sites and group them accordingly. Figure 8 contains the k-means results including three classes . Transitional sites were identified by creating a 4-class result . The topic compositions of sites in each cluster were examined and the clusters were given descriptive names reflecting their dominant topics : Innovation, Community, and Access. The transitional sites – those that broke off into their own group in the 4-class result – were signified using an overlaid line pattern. These sites were close to or straddled the center axes of the map.The Innovation cluster was distinct from the other clusters. The predominant topic amongst this group was innovation, which includes words and phrases like rooftop farming, zero-acreage farming, soilless, aquaponics, buildings, hydroponic, vertical, greenhouses, indoor, and technology as well as production, yield, growth, and quality. Unsurprisingly, all of the technologically-advanced sites resided in this cluster with the exception of Valley View Farms, which experiments with hydroponics, but focuses primarily on animal farming. Among the topic loadings in this group were community gardening, food access, social movements, climate change, water management, food production, and food security. This cluster also consisted primarily of for-profit growing sites with the exception of Roger’s Community Garden located on the University of California, San Diego campus. An interesting outlier is Go Green Agriculture, a hydroponic farm, which is located on the border of the Community cluster. This location is likely driven by its top topics, which include community gardening, location, and climate change, which are well-represented in both the Innovation and Community cluster. The Community cluster emphasized connections with local residents, primarily promoting home and community gardening – community gardening was the most prevalent topic in this cluster.

Although, this cluster overlaped considerably with the Access cluster, there was a clear emphasis on environmental topics including ecosystem conservation, water management, location, water contamination, innovation, and climate change. The social movement topic was also prevalent throughout this cluster with many of its sites expressing a dedication to alternative forms of organization. It is also worth noting that the socio-economic characteristics of the two neighborhoods are also quite different. Southeastern San Diego, specifically zip-code 92102 where Mt. Hope Community Garden is located, is a primarily Hispanic community, followed by White , African American , and Asian . The median income is at $42,464 with only 24 percent of the population exceeding $75,000 annually . The sites and organizations in this cluster also placed considerably less emphasis on environmental topics in favor of more social topics including public health, food production, and urban greening. Still, topics like ecology and climate change were present suggesting that environmental and social concerns were not mutually exclusive. The sites in the Access cluster were also predominantly affiliated with educational and training programs. Two particularly interesting examples are UrbanLife Farms and Second Chance Youth Garden. Both growing sites are wings of social justice organizations that offer job training and skills development for youth living in City Heights and Southeastern San Diego – communities that have seen considerable disinvestment and suffer from high unemployment . Other growing sites like Rolling Hills Grammar School and Literacy Garden and Olivewood Gardens and Learning Center also focus on youth programming. Not all the growing sites in this cluster work with youth. New Roots Farm concentrates on providing resettled refugees with land for farming, small-business training, and nutrition education to help them adjust to a new life away from their home country. This mission guided its topic loading of food security, social movements, and food access. The five urban agriculture supporting organizations we surveyed spanned the Community and Access clusters. Slow Food San Diego, Slow Food Urban San Diego, San Diego Roots Sustainable Food Project , and San Diego Community Garden Network are located in the Community cluster. San Diego Food System Alliance was located at the border between the Community and Access clusters suggesting that food access was a more prominent topic for the organization. Further, its central position illustrated the consensus focus of the organization, which caters to a diverse group of actors including politicians, businesses, and nonprofit organizations. Overall, the placement of the organizations made sense as they are nonprofit facilitators for other sites aimed at broader social goals like increasing food access and building community.