Month: December 2023

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GDP-L-galactose is synthesized from GDP-mannose in the cytosol by GDP-mannose epimerase

In the dwarf Arabidopsis mutant murus 1 L-galactose replaces L-fucose in several cell wall polysaccharides, including RGII, because the plant is unable to produce GDP-fucose in its shoots as it lacks GDP-D-mannose-4,6-dehydratase GMD1 . This has been shown to result in the incomplete formation of the A side-chain of RG-II, which in turn reduces the stability of the borate cross-linked dimer . Thus, the structural integrity of RG-II is probably important for its biological functions. Pectic and hemicellulosic polysaccharides are synthesized in the Golgi apparatus using activated donor substrates, typically in the form of nucleotide diphosphate-linked sugars . However, most NDPsugars are synthesized in the cytosol . Thus, NDP-sugar transporters are required to provide substrates for glycan synthesis . The Golgi-localized NST sub-family, which forms part of clade IIIa of the NST/triose phosphate transporter super family , comprises four members related to GONST1 , the first nucleotide sugar transporter described in Arabidopsis . The members of this family are the only Arabidopsis NSTs that contain a predicted GDP-binding motif . Arabidopsis is known to synthesize four GDP-linked sugars: GDP-L-fucose, GDP-L-galactose, GDP-D-glucose and GDP-D-mannose. GDP-mannose for the glycosylation of glycosylinositolphosphorylceramides is transported into the Golgi by GONST1 , whereas GDP-fucose is transported by GONST4, which has been renamed GDPfucose transporter1 . No Golgi-localized GDP-L-galactose transporters have been identified to date.Most GDP-L-galactose is then converted, via L-galactose, into L-ascorbate ,macetas 5 litros which is important for maintaining redox balance in the cell, particularly under abiotic or biotic stress .

However, some GDP-Lgalactose is required for cell wall polysaccharide synthesis since L-galactose is present in side chain A of RG-II, in the side-chains of xyloglucan from a limited number of plant species  and in corn bran glucuronoarabinoxylan . Here we provide evidence that GONST3 probably encodes a Golgi-localized GDP-L-galactose transporter, which we rename Golgi GDP-L-galactose transporter1 . We used RNA interference to suppress GGLT1 expression in Arabidopsis, since complete loss of GGLT1 is lethal. Plants with decreased GGLT1 expression have growth defects, which are rescued by increasing the amount of borate in their growth medium. Chemical analysis of the cell walls of GGLT1 knock-down plants revealed a substantial reduction in the L-galactose decoration of RG-II, which is correlated with a decrease in the proportion of RG-II dimer in the wall and a decrease in the stability of the crosslink. Our results underscore the importance of RG-II to plant survival, and highlight an unexpectedly critical role for L-galactose in borate crosslinking of this unusual pectic polysaccharide.Publicly available gene expression data reveal that GGLT1 is a ubiquitously expressed gene, with a level of expression that is slightly lower than GONST1 and GFT1 . In an earlier study, the subcellular localization of GGLT1 was not determined because tagged GGLT1 could not be expressed in vivo . To overcome this issue, the full-length GGLT1 coding sequence tagged with a fluorescent protein was introduced into onion epidermal cells by biolistic transformation. Confocal imaging revealed that the fluorescently tagged GGLT1 gave a punctate signal that co-localized with a Golgi marker .No Arabidopsis lines carrying a T-DNA insertion in the GGLT1 open reading frame have been reported. A single T-DNA line , with an insertion 841 bp upstream of the start of transcription was obtained, but we were unable to identify any plants homozygous for the TDNA insertion despite screening at least 30 different seedlings. Therefore, we took a targeted gene-knockdown approach and generated RNAi transgenic lines with a hairpin RNA construct, which specifically targeted GGLT1. Forty independent hpGGLT1 transformants were screened, and four were selected for characterization . These lines all had rosettes which were smaller than the empty vector control .

Quantitative real-time PCR showed that in the rosette leaves of the hpRNAi lines 1–3 the levels of GGLT1 silencing were similar . These data, together with the lack of T-DNA lines, suggest that stronger suppression of GGLT1 or null mutants will produce plants that are not viable. The expression of GFT1, the closest homolog of GGLT1, was not affected in lines 3 and 4 but was decreased by up to 50% in lines 1 and 2 . The monosaccharide compositions of the walls, including fucose, were not significantly altered in any of the hpRNAi lines , indicating that their phenotypes do not result from altered fucosylation of cell wall glycans and are thus a consequence of GGLT1 silencing. Moreover, the shortened petiole phenotype that is characteristic of silenced GFT1 plants as well as mur1 plants, which also have cell walls with reduced fucose , was not observed in our hpGGLT1 knock-down lines .L-Galactose replaces L-fucose in the xyloglucan formed by mur1 and GFT1-silenced plants where GDP-fucose synthesis or transport is perturbed . Since GGLT1 and GFT1 are closely related NSTs, we first determined if xyloglucan fucosylation is altered in hpGGLT1 . No differences were discernible in the matrix-assisted laser desorption–ionization time-of-flight mass spectra of the oligosaccharides generated by enzymatic fragmentation of the xyloglucan from hpGGLT1 and EV control lines . The presence of fucosylated side chains, together with no substantial increase in the abundance of galactosylated side-chains in the hpGGLT1 lines, supports our assertion that GDP-fucose transport is unaffected in the silenced plants. GGLT1 is in the same NST subclade as GONST1, which provides GDP-mannose specifically for GIPC glycosylation, as opposed to polysaccharide biosynthesis . Although glycosylation of GIPCs is still poorly understood, it is possible that other GDP-sugars, inaddition to GDP-mannose are required. Therefore, we used thin layer chromatography and LC-MS to determine the GIPC glycan composition of hpGGLT1. No major differences were discernible between hpGGLT1 and EV GIPCs. The overall sphingolipidomic composition was also unchanged . Together, the combined results of these studies show that GGLT1 does not encode a Golgi-localized protein involved in the transport of GDP-L-fucose or GDP-D-mannose. Thus, we next investigated if the L-galactose content of the wall was altered in the GGLT1 suppressed lines.

No significant differences were detected in the wall monosaccharide compositions of leaves from soil-grown EV and hpGGLT1 lines . This is not surprising since in primary cell walls D-galactose is far more abundant than L-galactose . Moreover, D-galactose and L-galactose are not separated when the monosaccharide composition of the cell wall is determined by high-performance anion exchange chromatography with pulsed amperometric detection . Rhamnogalacturonan-II is the only known L-galactosecontaining polysaccharide present in wild-type Arabidopsis cell walls, so we next determined whether the structure of RG-II differed in hpGGLT1 and EV plants. Material enriched in pectic polysaccharides, including RG-II, was obtained by extracting hpGGLT1 and EV leaf alcohol-insoluble residue with ammonium oxalate, a calcium chelator. This material was then treated with endopolygalacturonase and the products separated by size-exclusion chromatography . This separates RG-II from RG-I and oligogalacturonides, and also separates the RG-II monomer and dimer. In EV control plants the dimer accounts for 77% of the total RG-II isolated from the wall. Somewhat unexpectedly, the dimer accounts for only 49% of the hpGGLT1 RG-II,macetas de 30 litros and makes up only 6% of the RG-II in mur1-1 . This led us to suspect that the ability of hpGGLT1 RG-II to form dimers or the stability of those dimers had been altered. The latter notion is supported by our SEC data for the RG-II released by EPG treatment of the AIR . Under these conditions, in the absence of a chelating agent, the dimer accounted for 97% of the RG-II in the EV control plants , 87% of the RG-II in the hpGGLT1 lines and 70% of the mur1-1 . These results, together with data showing that calcium chelators partially convert the RG-II dimer to the monomer , strongly suggest that both the extent of formation and the stability of the borate cross-link in RG-II are affected in the hpGGLT1 lines. The differences in dimer abundance in the EPG and oxalate fractions were most pronounced with mur1-1 plants. This mutant produces RG-II that lacks L-galactose because its A side-chain is truncated , which led us to suspect that the L-galactose content of side-chain A of the RG-II from the hpGGLT1 lines may also be reduced. To determine if RG-II structure is indeed altered in the hpGGLT1 lines we isolated the total RG-II from the silenced and EV plants. Glycosyl residue composition analyses showed that D/L-galactose was reduced by about 35% in the most strongly affected hpGGLT1 lines . We then treated the RG-II with warm trifluoroacetic acid  to release side chains A and B. The MALDI-TOF MS analysis showed that a substantial portion of side-chain A from hpGGLT1 RG-II existed as a heptasaccharide whereas virtually all the A chain from the EV control was present as an octasaccharide . The A side-chains produced by hpGGLT1 and EV plants differ in mass by 162 Da, corresponding to a hexose residue, which we consider likely to be L-galactose. The side-chain B of RG-II contains a D-galactose residue . However, no differences were discernible in the structures of this side-chain from RG-II of hpGGLT1 and EV plants . Our structural data provide compelling evidence that the abundance of terminal L-galactose present on the A side-chain of RG-II is specifically affected in hpGGLT1 plants. To confirm the identity of the missing hexose in sidechain A, the RG-II monomers generated from the hpGGLT1 and EV plants were treated with a recently identified a-Lgalactosidase 95 from Bacteroides thetaiotaomicron that specifically removes the terminal L-galactose from side-chain A of RGII .

Galactose was the only monosaccharide detected by HPAEC-PAD following hydrolysis of EV control RG-II with the a-L-galactosidase . Less galactose was released from the RG-II of the hpGGLT1- silenced lines relative to the control . The MALDI-TOF MS analysis of side-chain A, released by mild TFA hydrolysis following a-L-galactosidase treatment of RG-II monomer, revealed that the predominant oligosaccharides in the EV control plants correspond to side-chain A lacking L-galactose . The L-galactose was almost completely removed as only low-intensity signals corresponding to L-galactosylated A side-chains were discernible . The mass spectra of side-chain A from both hpGGLT1 silenced lines are similar to that of the EV control , demonstrating that the mass difference of 162 Da between the EV control and hpGGLT1 lines in Figure 3 is due to the specific loss of L-galactose. It has been proposed that pectin domains may be linked covalently to each other or to other cell wall components . To investigate whether the altered RG-II structure in the hpGGLT1 silenced lines had affected other pectic domains, the oxalate cell wall fraction was used to perform immune dotblots with a panel of antibodies raided against different pectin epitopes . However, no difference was observed between the EV control and the silenced lines. In combination with the monosaccharide composition data and the xyloglucan data we conclude that the reduction in GGLT1 expression does not affect non-RG-II polymers. These data provide strong evidence that silencing of GGLT1 leads to a reduction in the abundance of L-galactose on side-chain A of RG-II, and provides additional evidence that the absence of this sugar leads to a decrease in the ability of the RG-II monomer to self-assemble into a borate cross-linked dimer. Moreover, this L-galactosedepleted dimer is less stable in the presence of calcium chelators than its wild-type counterpart, a result consistent with the notion that interactions of borate and calcium with RG-II are important for plant growth .Several growth phenotypes, including the dwarf phenotype of mur1, that have been attributed to defects in RG-II structure and cross-linking have been reported to be rescued by supplementing the growth medium with additional borate . To further explore the observed growth phenotypes of the hpGGLT1 lines , plants were grown hydroponically to control the availability of all macro- and micro-nutrients, including borate. In low-borate media the hpGGLT1 lines are severely stressed, and their rosette diameter is about 70% smaller than that of EV control plants . However, this phenotype is not observed when the silenced plants are grown in high-borate media . The amount of borate in the growth medium did not affect GGLT1 expression, thereby excluding a potential effect of borate deficiency or supplementation on transgene expression and silencing strength . Therefore, we conclude that partial loss of the RG-II L-galactose decoration in hpGGLT1 reduces the rate of RG-II borate-dependent dimerization, directly affecting plant development.

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How Does A Nft Hydroponic System Work

Methyl paraben is a preservative that is widely used in various cosmetic products, is amongst the most frequently detected parabens in TWW and bio solids, and is a known endocrine disruptor . Several studies have examined the fate and toxicity of these compounds in aquatic organisms . The observed adverse effects on aquatic organisms have raised concerns about the unintended consequences from widespread consumption and, ultimate release of the CECs into the aquatic environment . With the increasing use of TWW and bio solids for agriculture, it is crucial to also understand the effects of these compounds on terrestrial organisms. In this study, we carried out laboratory experiments to assess the potential uptake, biotransformation, and biochemical effects of CECs in earthworms. Eisenia fetida was exposed to the four CECs in an artificial soil, and kinetics of the parent compound, uptake and metabolite formation were evaluated. Changes in enzymes associated with oxidative stress and lipid peroxidation were assessed as biochemical markers of potential toxicity.Preliminary experiments were carried out to assess any potential mortality from the test compounds on E. fetida . The uptake and bio–accumulation of the test compounds followed OECD guideline on “Bio–accumulation in Terrestrial Oligochaetes.” Tests were performed in glass jars painted black and then white to reduce light and heat absorption. Jars contained 150 g ± 0.5 of artificial soil with 3 worms in each container. The worms were allowed to acclimate to the test conditions for 24 h before exposure to the test compounds. The incubation was carried out at room temperature.

Prior to spiking, maceta 5 litros earthworms were removed from jars and soils were spiked with different volumes of the standard stock solutions to arrive at initial concentrations of 70, 50, 275, and 200 ng g-1 for sulfamethoxazole, diazepam, naproxen and methyl paraben, respectively. Soils were moistened with deionized water, homogenized by stirring, and the earthworms were then reintroduced. Concentrations were selected based on environmental concentrations previously reported in the literature . Moisture content of 50% was selected based on preliminary experiments and maintained during the incubation. Jars containing the spiked soil without E. fetida and non-spiked soil with E. fetida were prepared and maintained simultaneously. At the start of the incubation, individual mature worms were maintained in separate jars to assess treatment-induced weight changes, if any. Samples were taken at 0 h, 1 d, 3 d, 7 d, 14 d, and 21 d of incubation. At each sampling time point, four treatment and four control jars were harvested for a total of twelve worms per time point per treatment. Worms were collected, rinsed with deionized water and placed in Petri dishes with a moistened paper towels for 24 h to purge their gut content. They were then weighed, frozen in liquid nitrogen and stored at -80 °C until extraction. The earthworms were homogenized with 8 mL acetonitrile:H2O for 5 min using a Kinematica™ Polytron PT 10/35 GT Benchtop Homogenizer . The CECs were extracted from the homogenized using 10 min of sonication, followed by 15 min of centrifugation at 15000 g. The supernatants were collected, dried under nitrogen, and reconstituted using 1.5 mL methanol:H2O . The reconstituted extracts were placed in LC-vials for analysis. Porewater was collected using 20 g of soil by centrifugation at 15000 g for 20 min, after which 2 mL of water was withdrawn and further centrifuged at 12000 g for 15 min. The resulting supernatant was used for instrument analysis. The soil was extracted by vortexing 10 g of soil with 10 mL acetonitrile:H2O for 5 min, followed by sonication for 20 min. Samples were centrifuged at 15000 g for 20 min, and the supernatant was collected, dried under nitrogen and reconstituted in 1.5 mL methanol:H2O . All extracts were filtered using 0.2 µm PTFE syringe filters before instrument analysis.

Extraction efficiencies were assessed using deuterated standards and are given in the Supplementary Information . Earthworm tissues were frozen in liquid nitrogen and then homogenized with 2 mL of 50 mM potassium phosphate buffer  with 1% polyvinylpyrrolidone and 1 mM ethylenediaminetetraacetic acid using a Kinematica™ Polytron PT 10/35 GT Benchtop Homogenizer . The homogenate was then centrifuged at 12 000 g for 20 min at 4 °C . The resulting supernatant was used for enzyme activity assays as described below. The activities of glutathione-S-transferase , catalase and superoxide dismutase were determined as in Sun et al. . To determine GST activity, 100 µL of supernatant was combined with 2 mL of a reaction mixture containing 50 mM PBS , 5 mM glutathione , and 1 mM 1-Chloro-2,4,- dinitrobenzene dissolved in 96% ethanol. The GST activity was measured at 340 nm for 3 min and the concentration was calculated using the GSH-CDNB adduct synthesis . The CAT activity was determined by combining 200 µL of supernatant with 3 mL reaction mixture containing 10 mM H2O2 in 50 mM PBS buffer . The concentration was calculated by following the consumption of H2O2 at 240 nm for 3 min . The activity of SOD was determined by combining 100 µL supernatant with 3 mL reaction mixture containing 50 mM PBS buffer , 13 mM methionine, 75 µM nitro blue tetrazolium , 2 µM riboflavin, and 0.1 mM EDTA. The mixture was illuminated for 15 min at a light intensity of 5,000 lux for 15 min. One unit of SOD activity was defined as the concentration of enzyme required to cause 50% inhibition of NBT when monitored at 560 nm. The protein content was used to standardize enzyme activity and determined by combining 5 mL of Coomassie Brilliant Blue G-250 reaction mixture and 100 µL of supernatant and use to standardize enzyme activity. Concentration was calculated from a six-point standard curve using bovine serum albumin monitored at 595 nm .All treatments in the E. fetida incubations experiments contained four replicates and mortality, if any, was assessed immediately upon stoppage. Standard calibration curves with r 2 values of at least 0.98, were made from standards of diazepam, naproxen, methyl paraben, sulfamethoxazole, nordiazepam, odesmethylnaproxen, p-hydroxybenzoic acid, N4-acetylsulfamethoxazole, diazepam-d5, naproxen-d3, sulfamethoxazole-d4, methyl paraben-d4 and used for quantification for all analytes. A limit of detection of 1 ng mL-1 and a limit of quantification of 5 ng mL-1 were determined for all analytes, except for p-hydroxybenzoic acid that had aLOD of 3 ng mL-1 and an LOQ of 5 ng mL-1 . LOD and LOQs were calculated from a signal to noise ratio of 3 and 10 respectively. Compound peaks were detected and integrated using TargetLynx XS software . Data were analyzed and graphed with StatPlus and Prism 8 GraphPad software . Results were calculated as the mean ± standard error , and a Student’s t-test or ANOVA with a Tukey-Kramer post-hoc was used to assess the systematic difference between groups . The concentrations of CECs were monitored in three phases, soil, soil pore water, and earthworm tissue, in both the presence and absence of earthworms throughout the 21 d incubation. To determine the potential effect of earthworms’ presence on the partitioning of the four CECs amongst the soil and soil pore water the distribution coefficient was calculated at each time point and the differences between earthworm treatment and the non-earthworm controls were compared . No significant differences in the Kd values were observed between the earthworm treatment and non-earthworm controls for any of the CECs,cultivo de la frambuesa indicating that earthworms did not significantly affect the association of these CECs to the solid phase of the artificial soil. For diazepam, the Kd values were calculated to range between 0.84 to 6.56 mL g -1 throughout the incubation. These Kd values were lower than those previously reported for diazepam in batch and field sorption measurements using agriculture soils  but were in agreement with the low Kd values observed for pharmaceuticals in sandy soils .

The low Kd values indicated that diazepam was not strongly adsorbed to the solid matrix of the artificial soil. The Kd for naproxen ranged between 0.87 to 11.0 mL g -1 throughout the incubation. The low Kd values were consistent with those previously reported for naproxen in sandy soils [0.49 mL g -1 ] The Kd values for sulfamethoxazole were similarly very low throughout the incubation, ranging from 0.71 to 1.75 mL g.-1 These values were consistent with those previously reported in the literature for grassland soils and arable land soils , indicative of its high mobility in the soil environment . The derived Kd values, for methyl paraben in the earthworm treatment and non-earthworm controls could be calculated only for the initial sampling point as it rapidly disappeared from the soil and soil porewater. This may be due to rapid biodegradation in the soil and/or rapid metabolism in E. fetida . To verify active uptake of CECs by earthworms, a range of controls were used, including soil blanks and non-earthworm controls. None of the parent CECs were detected in the earthworm or soil blanks. However, degradation of both methyl paraben and sulfamethoxazole was observed in the non-earthworm soil, indicating that microbial and/or abiotic degradation of these compounds occurred in the media . The parent compounds of diazepam, sulfamethoxazole, and naproxen were detected in earthworms throughout the 21 d incubation, with the concentration of both diazepam and naproxen increasing to 53.8 ± 24 ng g-1 and 110 ± 25 ng g-1 , peaking at 14 d. These results suggested that both diazepam and naproxen were being taken up and accumulated in E. fetida . Sulfamethoxazole, on the other hand, appeared to have a relatively stable concentration in the earthworm tissues throughout the incubation . However, this could be due to active metabolism of sulfamethoxazole in earthworm instead of limited uptake or accumulation. Methyl paraben was not quantifiable in earthworm tissues and was rapidly lost in the artificial soil. For each of the three quantifiable CECs in the earthworm tissues , the bio–concentration factor and bio–accumulation factor were calculated and compared for each time point. No significant differences in the BAF were observed for sulfamethoxazole or naproxen over the course of the incubation . However, the BAF for diazepam did significantly increase over time , indicating that the increased exposure time to soil pore water resulted an increased concentration of diazepam in the earthworm tissues, likely due to slower metabolism or time needed for reach equilibrium. The BCF for diazepam and naproxen did not significantly change throughout the incubation period . For sulfamethoxazole the a significant difference in BCF was observed between the 3 d and the 14 d sampling points, but no clear pattern in BCF values over time was discernable. A significant difference between BAF the BCF values were observed for sulfamethoxazole at 7 d . There was a trend towards a significantly higher BCF than BAF for diazepam throughout the incubation. The trend may be due to increased uptake of the compounds from the soil pore water by E. fetida, which was consistent with several previous studies that showed dermal absorption via water to be the primary route for uptake of contaminants by worms . However, due to a lack of quantifiable replicates in soil or soil pore water statistical significance could not be assessed. Further research is necessary to understand the exposure pathways for polar CECs for invertebrates such as in earthworms in soils. Intriguingly, it was also observed that all three quantifiable CECs displayed an similar pattern where there was an initial increase in BAF or BCF up to 3 or 7 d, followed by a decrease at 7 or 14 d, and followed by increases again till the end incubation . This pattern may be indicative of early uptake and metabolism, followed by an insufficient response from detoxification enzymes, resulting in storage and accumulation of the compounds in the earthworm tissues, as was previously observed in aquatic organisms . To the best of knowledge, this was the first time the BCF and BAF have been calculated in earthworms for naproxen, diazepam and sulfamethoxazole. While many studies have considered the bio–concentration/accumulation of different CECs in plants and earthworms , very few studies have considered the changes to these values over time.

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¿Cuáles son las ventajas de elegir macetas plásticas en comparación con otros materiales?

Elegir macetas plásticas en comparación con otros materiales tiene varias ventajas. Aquí hay algunas razones por las cuales algunas personas prefieren macetas de plástico:

  1. Ligereza: Las macetas de plástico son más ligeras que las macetas de cerámica o terracota, lo que facilita su manejo y movimiento. Esto es especialmente útil si necesitas trasladar las plantas con frecuencia.
  2. Durabilidad: Las macetas de plástico son duraderas y resistentes a la intemperie. No se rompen fácilmente y pueden soportar condiciones climáticas adversas sin deteriorarse.
  3. Retención de humedad: Las macetas de plástico tienden a retener mejor la humedad que las macetas de terracota o cerámica. Esto puede ser beneficioso para algunas plantas, ya que ayuda a mantener un ambiente más constante para el sistema radicular.
  4. Variedad de formas y tamaños: Las macetas de plástico ofrecen una amplia variedad de formas, tamaños y colores. Esto brinda opciones estéticas y funcionales para adaptarse a diferentes necesidades y preferencias.
  5. Asequibilidad: En general,maceta 5 litros las macetas de plástico tienden a ser más asequibles que las macetas de materiales como cerámica o terracota. Esto las hace una opción económica para jardineros aficionados.
  6. Facilidad de limpieza: Las macetas de plástico son fáciles de limpiar y desinfectar, lo que ayuda a prevenir enfermedades de las plantas. También son menos propensas a acumular sales minerales.
  7. Aislamiento térmico: Las macetas de plástico proporcionan un mejor aislamiento térmico para las raíces de las plantas, lo que puede ser beneficioso en climas extremos.

A pesar de estas ventajas, es importante destacar que cada tipo de material de maceta tiene sus propias características y puede ser más adecuado para ciertos tipos de plantas o situaciones. Además, algunas personas prefieren materiales más naturales por razones estéticas o ambientales. La elección de la maceta dependerá de tus necesidades específicas y preferencias personales.

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¿Dónde puedo comprar macetas plásticas al por mayor?

Para comprar macetas plásticas al por mayor, puedes considerar varias opciones. Aquí hay algunas sugerencias:

  1. Distribuidores de Jardinería y Artículos para el Hogar: Busca distribuidores especializados en productos de jardinería y artículos para el hogar. Muchos de ellos ofrecen macetas plásticas en grandes cantidades a precios mayoristas.
  2. Mayoristas en Línea: Explora plataformas en línea que se especializan en la venta al por mayor. Hay sitios web que conectan a compradores con proveedores de productos de jardinería,maceta 40 litros donde puedes encontrar macetas plásticas en grandes cantidades.
  3. Ferias Comerciales y Exposiciones: Participar en ferias comerciales o exposiciones relacionadas con la jardinería y la horticultura puede proporcionarte la oportunidad de conocer a proveedores y fabricantes de macetas plásticas al por mayor.
  4. Contacta a Fabricantes Directos: Algunos fabricantes de macetas plásticas pueden vender directamente al por mayor. Ponte en contacto con ellos para conocer sus opciones de compra a granel y sus términos.
  5. Tiendas de Suministros para Agricultura: Las tiendas especializadas en suministros para la agricultura y la jardinería suelen ofrecer productos al por mayor. Investiga tiendas locales o regionales que se centren en este tipo de suministros.
  6. Empresas de Suministros de Jardinería: Busca empresas especializadas en suministros de jardinería y paisajismo. Estas compañías a menudo tienen opciones de compra al por mayor para clientes comerciales.

Recuerda comparar precios, términos de envío y políticas de devolución antes de tomar una decisión. Además, verifica la reputación del proveedor para asegurarte de que sea confiable y ofrezca productos de calidad.

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Seleccionar las Macetas de Plást

Cuando se trata de tener éxito en la jardinería, la elección de los recipientes es tan importante como la elección de las plantas. Las macetas de plástico, con su versatilidad y durabilidad, se han convertido en una opción popular tanto para la jardinería interior como la exterior. Sin embargo, seleccionar el tipo correcto de maceta de plástico es crucial para garantizar un crecimiento y salud óptimos de las plantas. En este artículo, exploraremos los diversos tipos de macetas de plástico y discutiremos cuáles son las más adecuadas para la jardinería interior y cuáles son ideales para uso en exteriores.

Jardinería Interior:

Macetas Livianas y Portátiles:

Para la jardinería interior, donde es posible que necesite mover las plantas para aprovechar la luz solar o reorganizar el diseño de su jardín interior,cultivo del arandano las macetas de plástico livianas y portátiles son una excelente elección. Busque macetas fabricadas con plásticos de alta calidad y livianos que sean fáciles de transportar y reorganizar. Atractivo Estético:

Muchos jardineros de interior priorizan el aspecto visual de sus contenedores de plantas. Las macetas de plástico decorativas con diversas formas, tamaños y colores pueden complementar la decoración de su interior. Opte por macetas que mejoren el atractivo estético general de su espacio interior. Macetas de Auto-Riego:

Las plantas de interior a menudo requieren un riego más preciso. Las macetas de plástico de auto-riego con depósitos incorporados pueden ayudar a mantener niveles de humedad consistentes, reduciendo el riesgo de riego excesivo o insuficiente. Esta característica es especialmente útil para personas ocupadas o aquellas nuevas en la jardinería. Jardinería Exterior:

Macetas Resistentes a los Rayos UV y Duraderas:

Las condiciones exteriores exponen las macetas de plástico a la luz solar intensa y a condiciones climáticas variables. Elija macetas fabricadas con plásticos resistentes a los rayos UV y duraderos para resistir la exposición prolongada al sol sin degradarse ni volverse quebradizas con el tiempo. Orificios de Drenaje:

Un drenaje adecuado es crucial para las plantas exteriores para evitar el encharcamiento, que puede provocar la pudrición de las raíces. Seleccione macetas de plástico con suficientes agujeros de drenaje para asegurar que el agua en exceso pueda escapar, fomentando sistemas radiculares saludables. Aislamiento para la Regulación de la Temperatura:

Las temperaturas exteriores pueden fluctuar significativamente. Las macetas de plástico aisladas ayudan a regular la temperatura del suelo, protegiendo las raíces de las plantas contra el calor extremo o el frío. Esto es especialmente importante para las plantas sensibles a las variaciones de temperatura. Recipientes Grandes para el Crecimiento de las Raíces:

Las plantas exteriores a menudo requieren más espacio para el desarrollo de las raíces. Elija macetas de plástico más grandes que proporcionen suficiente espacio para que las raíces se expandan,frambueso maceta fomentando un crecimiento saludable y la estabilidad, especialmente para plantas o arbustos más grandes. Consideraciones Generales:

Materiales Reciclables:

La sostenibilidad es una consideración clave. Busque macetas de plástico fabricadas con materiales reciclables, contribuyendo a los esfuerzos de conservación del medio ambiente. Facilidad de Limpieza y Mantenimiento:

Tanto las macetas de interior como las de exterior deben ser fáciles de limpiar y mantener. Superficies lisas y materiales resistentes a manchas y moho facilitan la jardinería sin complicaciones. Opciones Económicas:

Considere su presupuesto al elegir macetas de plástico. Hay opciones económicas disponibles sin comprometer la calidad. Busque macetas que ofrezcan un equilibrio entre asequibilidad y durabilidad. Conclusión:

En conclusión, las macetas de plástico adecuadas para sus esfuerzos de jardinería dependen de factores como la ubicación, el tipo de planta y las preferencias personales. Al seleccionar macetas adaptadas a sus necesidades específicas, puede crear jardines interiores y exteriores prósperos que no solo muestren la belleza de sus plantas, sino que también mejoren su experiencia general de jardinería.

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Maximize Growth Potential: Unleashing the Power of Hydroponic Grow Systems

Given that Huanglongbing is related to ROS-overproduction, ROS-modulating NMs may have significant impact on the disease course. In the nanozyme field, novel ROS-triggering nanozymes are constantly being synthesized. NADPH oxidase, also referred to as RBOH, is a transmembrane enzyme complex that controls the generation of superoxide, which plays an important role in immune signalling pathways. A recent study synthesized a Fe–N-doped graphene nanomaterial that could mimic the activity of NADPH oxidase by efficiently catalysing the conversion of NADPH into NADP+ , subsequently triggering the generation of oxygen radicals. Given these demonstrated ROS-generating properties, FeNGR nanozymes may be applied to cultivate stress-resistant crops. To date, no studies have employed this nanozyme with NADPH oxidase-like activity for stress tolerance enhancement. Thus, the linkage between plant science and nanozyme fields of study could significantly move this field forward. Last, applications of NMs in agriculture need to consider the potential environmental and human health risks. For example, the impacts of NMs on non-target biota needs to be evaluated. The impacts of NMs on soil microbial and fungal communities that are critical to nutrient uptake of plants, as well as carbon and nitrogen cycling, must be evaluated. In addition, the bio-accumulation of NMs, particularly in edible tissues, needs to be investigated to avoid potential transfer in food chains that could negatively impact human or ecosystem health. However, it is clear that sustainable nano-enabled strategies to promote crop species’ tolerance to abiotic and biotic stresses Several studies report the uptake of emerging contaminants from hydroponic solutions, spiked soils and soil irrigated with TWW or amended with bio-solids or animal manure . However,plastic plant containers these studies often report conflicting or contradictory results concerning the rate of uptake and the extent of translocation.

Hydroponic studies often exhibit higher rates of uptake than those observed in spiked or amended soils studies. For example, in a study conducted by Boonsaner and Hawker the maximum concentration of antibiotics in plant tissues was reached within 2 d in spiked water but took 6-8 d when plants were grown in contaminated soils. In hydroponic systems, plant uptake and translocation are largely driven by the contaminants water solubility, log Kowand/or the pH of the hydroponic solution and the potential for ionization, log Dow, . Whereas in soils, soil-specific processes such as soil-pore water partitioning, and transformations in soil, also contribute to contaminant uptake and accumulation in plants. Thus, the uptake rate and translocation of a contaminant in plants can vary widely depending upon soil and environmental conditions. For example, a soil with higher organic matter content can limit plant uptake of organic contaminants, due to stronger contaminant adsorption than a soil with lower organic matter content . Also, shifts in soil pH can result in ionization of ionizable organic contaminants, affecting the rate of plant uptake . Antibiotics constitute one of the most extensively used pharmaceuticals classes for both human and livestock and as such are nearly ubiquitously detected in wastewater effluent, bio-solids and livestock manure . Relatively more studies have been reported on terrestrial plant uptake and translocation of antibiotics than other pharmaceuticals in the agro-environment, including studies conducted in hydroponic growth solutions, greenhouses, and under field conditions .In hydroponic growth solution, the antibiotic sulfamethoxazole was taken up in the roots and translocated to leaves of four vegetable plants, including lettuce , spinach , cucumber , and pepper plants , with the concentration report to be significantly greater in the roots .

In a 55 day hydroponic study, three antibiotics, i.e., tetracycline, cephalexin, and sulfamethoxazole, were found to be taken up and translocated into edible tissues of pakchoi , with concentrations ranging from 6.9 – 11.8, 26.4 – 48.1, and 18.1 – 35.3 µg kg-1 for tetracycline, cephalexin and sulfamethoxazole, respectively . Several studies have also explored plant uptake of antibiotics from spiked soils . For example, Boxall et al., exposed carrot and lettuce plants to soils spiked with 1 mg kg-1 of 7 antibiotics, i.e., sulfadiazine, trimethoprim, tylosin, amoxicillin, enrofloxacin, florfenicol, and oxytetracycline. After 103 d and 152 d cultivation, antibiotics were quantified in both crops. However, the concentrations varied considerably among different antibiotics and between plant species. For example, amoxicillin was detected at < 1 µg kg-1 in lettuce tissues but was 24 µg kg-1 in carrot tissues . Three sulfonamides, i.e., sulfadiazine, sulfamethazine, and sulfamethoxazole, were also reported to be taken up by pakchoi cultivated in spiked-soils, with sulfamethoxazole having the highest concentration among the three antibiotics throughout the 49 d cultivation . To better predict environmentally relevant risks from antibiotic uptake to human consumption, several studies have been carried out on crops grown in soils irrigated with spiked TWW and/or amended with livestock manure . These studies showed that food crops were capable of taking up and accumulating antibiotics from wastewater and/or manure-amended soils; however, the levels were often very low. For example, chlortetracycline was taken up by corn , green onion , and cabbage that were grown in soils amended with antibioticspiked manure . However, the concentrations were low . Sulfamethoxazole and lincomycin were found to accumulate in lettuce tissues at concentrations up to 125 µg kg-1 and 822 µg kg-1 , respectively, after irrigation with antibiotic-spiked synthetic wastewater at 1 mg L-1 , . Similarly, in field studies, crops irrigated with TWW were found to take up antibiotics, including but not limited to, roxithromycin, clindamycin, ciprofloxacin, sulfamerazine, and sulfamethoxazole . However, in nearly every case the concentration of antibiotics in plant tissues was negligibly low. Nonsteroidal anti-inflammatories are the most commonly consumed class of pharmaceuticals in the world .

As such they are ubiquitously found in TWW, bio solids, and surfaces water . They have been reported to accumulate in soils that receive TWW or bio solids . Several studies have explored the potential for uptake and translocation of NSAIDs in plants, including in hydroponic systems, amended soils, and field studies . NSAIDs have a wide range of physicochemical range properties and, as such, have displayed vastly different uptake and translocation rates . For example, in a hydroponic study the NSAID diclofenac was observed to accumulate only in the roots of four vegetables while relatively high levels of acetaminophen were detected in the leaves . Similarly, a study exploring plant uptake of 14C labeled naproxen and diclofenac from hydroponic solutions showed that two vegetables, i.e., lettuce and collard greens , were capable of accumulating both compounds, and both plants accumulated significantly more diclofenac than naproxen . Radish and ryegrass were shown to absorb and accumulate diclofenac from soils spiked with the chemical at an initial concentration of 1 mg kg-1 . However, after 40 d cultivation, the concentration of diclofenac in the plants was very low < 1 µg kg-1 . Greenhouse studies using soils amended with bio solids and field studies using TWW irrigation considered the uptake of NSAIDs under environmentally relevant conditions. For example, Cortés et al. conducted a greenhouse study in which soybeans and wheat were cultivated in bio solids-amended soils for 60 and 110 d. However, none of the four NSAIDs was detected in the plant shoots. On the other hand, in a long-term field study , diclofenac was found relatively high levels in the fruits of tomato plants after prolonged irrigation with TWW, as compared to sulfamethoxazole and trimethoprim . Further, in another field study, naproxen was detected in the edible tissues of various vegetables irrigated with TWW or TWW fortified with the chemical at 250 ng L-1 and grown until maturity . Several NSAIDs have also been considered in the investigation of potential metabolism of pharmaceuticals in plant cell cultures and whole plants . The metabolism of diclofenac was investigated in four different plant systems, including a horseradish hairy root culture , barley , Arabidopsis thaliana cell culture,blueberry container and Arabidopsis thaliana whole plants . However, the formation of diclofenac metabolites differed significantly by plant systems. For instance, while phase I hydroxylation was observed in all the systems, the horseradish hairy root cultures and barley formed a glucopyranoside as the major Phase II metabolite . Arabidopsis thaliana, on the other hand, produced acyl-glutamatyl-diclofenac as the major Phase II metabolite via direct conjugation . Direct conjugation of naproxen and ibuprofen with glutamic acid and glutamine was also observed in Arabidopsis thaliana plants . The metabolism of acetaminophen has also been studied in multiple plant systems, including horseradish hairy root cultures and Indian mustard . In these studies, direct glucuronisation, glucosidation, and sulfation were observed along with the formation of a reactive metabolite N-acetyl-pbenzoquinoneimine . Taken together these studies have highlighted the ability of plants to uptake and transform NSAIDs. Several classes of psychiatric pharmaceuticals have been detected in TWW and bio-solids including antidepressants, mood stabilizers, and antianxiety agents . Of these compounds, carbamazepine has been likely considered in probably the most in the agroenvironment due to its stability during wastewater treatment and in the environment .

Carbamazepine has been often reported to be taken up by plants in both field and laboratory settings . In hydroponic systems, carbamazepine has been shown to accumulate in both roots and shoots of multiple plant species, including lettuce, spinach, cucumber, and peppers . Cucumber was found to readily translocate carbamazepine when cultivated in hydroponic systems . However, a high rate of translocation was not observed in cabbage plants cultivated in hydroponic systems . In greenhouse studies, carbamazepine was reported to be taken up by cucumbers and ryegrass grown in soils irrigated with TWW and urine . In addition, Shenker et al., reported that uptake into cucumbers was negatively correlated with soil organic matter content. In fields irrigated with TWW, trace levels of carbamazepine was found to accumulate in different parts of various vegetables . Carbamazepine was also reported to transfer to humans after consumption of contaminated vegetables . The metabolism of carbamazepine in plants has also been investigated . In carrot cell cultures five phase I metabolites of carbamazepine were observed to form over 22 d . Further, 10,11-epoxycarbamazepine and 10,11-dihydroxycarbamazepine have been reported in carrots and sweet potatoes grown in fields irrigated with CEC-spiked TWW . Fluoxetine is an antidepressant prescribed for both human and animal consumption , resulting in fluoxetine being commonly detected in environmental samples . In hydroponic cultivations fluoxetine was taken up by cauliflower and accumulated in the stems and leaves . In a greenhouse study exploring plant uptake of fluoxetine from soils irrigated with TWW and amended with bio solids fluoxetine accumulated in the roots , but, it was not translocated to the leaves . In addition, fluoxetine displayed an opposite uptake pattern to that for carbamazepine, and showed a greater accumulation in plants grown in bio-solid-amended soils as opposed to soil irrigated with TWW . Benzodiazepines, are one of the most prescribed classes of pharmaceuticals . Of these, diazepam is among the most commonly detected pharmaceuticals in TWW, with concentration ranging from ng L-1 to low µg L-1 . Benzodiazepines have been shown to be taken up and accumulate in tissues of plants grown in treated hydroponic solutions or soils . In hydroponic solutions, diazepam has been observed to accumulate in both the leaves and roots of lettuce, spinach, cucumber, and pepper with BCF of 10-100 ]. Further, in a greenhouse study exploring the uptake of seven benzodiazepines , both silver beets and radish crops took up and accumulated all seven benzodiazepines from the treated-soil . Oxazepam was found to have the highest accumulation in both plants, with concentrations up to 14.2 µg g-1 in silver beets and 5 µg g-1 in radishes . However, the fate of these pharmaceuticals in the agro-environment is still relatively unexplored, even though their physicochemical properties indicate a high potential for uptake by plants .A multitude of antimicrobials and preservatives are used in health and grooming products, collectively known as personal care products . Personal care products have garnered increased scientific attention due to their presence in surface waters and concerns that some of these antimicrobials and preservatives may be endocrine disruptors . Of these, triclocarban and triclosan have been amongst the best studied compounds in the terrestrial environment due to their ubiquitous occurrence in bio-solids and relative stability in soils after bio-solid application .

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Growing Up Without Ground: The Basics of Hydroponic Crop Cultivation

There may be some regulation controlled by a threshold value for Cd plant status, in both species. Long-term contamination with 0.1 µM would be below this threshold, thanks to the PC sequestration for example. On the other hand, long-term contamination with 10 µM would exceed this limit and result in down-regulation of the transport proteins of the HATS, possibly because of excess free Cd in the cytosol or because of some signal from the shoots. For both plants, cell wall sorption efficiency appears to be improved by the high Cd concentration in the growth solution, whereas the low concentration had generally no significant impact. The increase in the cell wall binding efficiency after high internal Cd accumulation may be related to the down-regulation of intracellular uptake. However, the reduction in symplastic influx is very low and cannot account for the increase observed at the apoplastic level. On the contrary, the up-regulation of the adsorption rate may well account for the decrease in the symplastic uptake. The apparent up-regulation of Cd binding properties may be due to modifications of the root cell-wall adsorption characteristics, particularly the root CEC. Cadmium stress is known to affect cell wall composition. First, Cd increases the proportion of acidic pectins . Secondly, the cell wall CEC may be increased through regulation of enzymes. For instance, pectinmethylesterase has been suggested to be stimulated in the outer cell wall domains of Cd-stressed plants, resulting in a strong decrease in the methylesterification of the acidic pectins. Thus, Cd strongly increases the acid pectins/esterified pectins ratio, hence the higher CEC, particularly in the middle lamellae . This low degree of esterification enhances the adsorption of all metallic trace elements , improving the plant tolerance of the metal. As dry mass did not vary with the level of contamination,40 litre pot there may be no significant difference in the proportion of young roots and then no decrease in the root CEC due to the age of roots.

Therefore, the insignificant effect of low Cd contamination on the apoplastic adsorption rate could be accounted for by the existence of some Cd-stress threshold below which there is no regulation mechanism. A long-lasting tolerance to aluminum ion is an essential phenotype for perennial plants growing on strong acid soils for longer periods. There is increasing evidence that plants with superior Al tolerances are relatively easily found in woody plants, such as tropical plantation trees Melaleuca cajuputi and Paraserianthes falcataria . Some woody plants, including tea, hydrangea, and Melastoma malabathricum, are also known as Al-accumulators that retain large amounts of Al in their above ground organs . However, the mechanisms responsible for high Al tolerance or high Al accumulation in woody plants remain to be elucidated. Our preliminary screening has successfully identified that root elongation in seedlings of Cinnamomum camphora, an evergreen tree widely distributed or planted in China and its neighboring regions, is much less inhibited even at high Al concentrations in a simple ionic solution at least for several days. Our finding is consistent with a study that reported no growth reduction in C. camphora seedlings against Al in a nutrient solution for 5 weeks . As a first step in understanding long-term Al tolerance mechanisms in seedlings of C. camphora, we employed a pulse Al exposure every two days for 60 days in measurements of root elongation and Al accumulation in each organ. To understand Al transport mechanisms in shoots, we also examined the Al accumulation patterns in branch cuttings of C. camphora. Root architecture influences nutrient and water uptake, anchorage, and mechanical support, interactions with microbes, and responses to various abiotic stress factors . Since water and mineral supply are often limited in the soil, a plant with a more extensive root system exhibits higher performance with regard to the tolerance of drought and poor nutrient conditions . Several factors, including root angle, root growth rate, and root types, influence root architecture . Root growth requires the successive formation of new cells from stem cells in the root apical meristem , and the progeny of such stem cells divide rapidly and enter the elongation/differentiation zone . To maintain root meristem activity, the rates of cell division and differentiation have to be coordinated .

Plant hormones greatly influence the balance between cell division and cell differentiation . In addition, the interaction between cytokinin and auxin determines the size of the RAM through the regulation of the genes involved in auxin signaling and/or transport to ensure an appropriate auxin gradient . The rice root system consists of one seminal root, numerous adventitious roots, and lateral roots that emerge from the other two types . Lateral roots are the major components involved in the absorption of nutrients and in interactions with the surrounding soil environment . Lateral root formation represents a complex developmental process modulated by several hormones, including auxin and ethylene . Well defined and closely coordinated cell division activities give rise to lateral root primordia . While lateral roots originate from pericycle cells adjacent to xylem poles in Arabidopsis , pericycle and endodermal cells located near phloem poles are the origins of lateral roots in rice and maize . Their development is initiated by the asymmetric division of the pericycle cells, and subsequent divisions result in the formation of dome-shaped, multilayered, lateral root primordia . After the initiation of asymmetric division, the primordia emerge, form active meristems, and break through the epidermal cells to become new lateral roots. Auxin is essential for various steps in the course of root development—from cell fate acquisition to meristem initiation, emergence, and elongation . In Arabidopsis, auxin is mainly synthesized in young apical tissues of the shoots and roots . Indole-3-acetic acid is considered the major form of auxin, with tryptophan being its precursor . Among the four pathways of IAA biosynthesis from Trp, the indole-3-pyruvic acid pathway is the major pathway in Arabidopsis . In the IPyA pathway, tryptophan aminotransferases convert Trp into IPyA, and YUCCAs synthesize IAA from IPyA, a rate-limiting step for the pathway .

In rice, FISH BONE encodes a Trp aminotransferase; loss of function results in pleiotropic abnormal phenotypes, which include small leaves with large lamina joint angles, unusual vascular development, and defects in root development, which are all consistent with a decrease in internal IAA levels . Mutations in CONSTUTIVELY WILTED1result in narrow and rolled leaves, in addition to the decreased growth of lateral and crown roots . Conversely, the over expression of OsYUC1 causes an increase in IAA accumulation, and auxin-overproducing phenotypes are observed . Such phenotypes are subject to the presence of the transcription factor WUSCHEL-RELATED HOMEOBOX 11 , a key regulator of root development . In rice, auxin induces WOX11 transcription,collection drainage which establishes the YUCCA–auxin–WOX11 module for root development . Ethylene also controls root development. Treatment with low concentrations of an ethylene precursor, 1-aminocyclopropane- 1-carboxylic acid , promotes the initiation of lateral root primordia. In contrast, exposure to higher ACC concentrations inhibits such initiation considerably, while also promoting the growth of already existing lateral root primordia . The regulation is linked tightly with auxin . For example, ethylene application results in the accumulation of auxin at the tip of Arabidopsis primary roots through the promotion of auxin synthesis mediated by WEAK ETHYLENE INSENSIVE2/ANTHRANILATE SYNTHASE α1 and WEI7/INSENSIVE2/ ANTHRANILATE SYNTHASE β1 . WEI2 and WEI7 encode the α and β subunits, respectively, of anthranilate synthase , a rate-limiting enzyme in the biosynthesis of the auxin precursor Trp . In rice, ethylene also increases endogenous IAA concentrations in the roots; however, the effect is minimized in mutants defective in YUC8/REIN7, which participates in auxin biosynthesis . The homeobox genes are critical for growth and development because they regulate cell fate and plant specificity . A family of zinc-finger homeodomain proteins has an N-terminal conserved domain containing several cysteine and histidine residues for potential zinc binding, in addition to a C-terminal domain containing a homeodomain . Most ZF-HD proteins do not have an intrinsic activation domain, which suggests that interactions with other factors are necessary for transcriptional activation . In addition, all 14 members of the ZF-HD gene family in Arabidopsis are predominantly expressed in floral tissues and play key roles in their development . One member, AtHB33, which is negatively regulated by ARF2, is required for seed germination and primary root growth . Among the 11 ZF-HD genes in rice, the over expression of OsZHD1 and OsZHD2 induces leaf curling by controlling the number and arrangement of bulliform cells . Here, we report that the over expression of OsZHD2 in rice improves root growth by enhancing meristem activity. We demonstrated that the homeobox protein elevated ethylene concentrations by increasing the transcript levels of ethylene biosynthesis genes. We further obtained ChIP assay data that revealed an interaction between OsZHD2 and the chromatin of ACS5. Analyses of transgenic rice plants carrying DR5::GUS and DR5::VENUS revealed that the expression of the DR5 reporter gene was induced following treatment with ACC, an ethylene precursor. The results suggest that OsZHD2 increases the biosynthesis of ethylene and subsequently auxin, which stimulates root growth.We isolated a rice mutant plant with an extensive root system from a population of activation tagging lines, in which the expression of a gene is enhanced by multiple copies of the 35S enhancer introduced using T-DNA .

In Line 3A-13017, the root biomass increased significantly . At 8 DAG the seminal roots were 27% longer in the activation plants than in the WT . Their lateral roots were also much longer than in the WT at a similar stage. At the upper parts of the seminal roots, the mutant lateral roots were 144% longer than those of the WT . This activation line also had more lateral roots—230 per seminal root for Line 3A-13017 versus 179 laterals per seminal root for the WT . However, the density of lateral roots did not differ significantly between the genotypes , which indicated that the increase in the number of lateral roots was largely due to the mutant plants having longer primary roots. We located T-DNA 5 kb downstream from the stop codon of OsZHD2 in the transgenic line . Its expression was significantly higher than that of the control, potentially because of the 35S enhancer elements in the T-DNA border region . We designated this activation line as OsZHD2-D.qRT-PCR analysis revealed that the expression level of OsZHD2 was significantly higher in the root tips when compared with levels in the total root . In addition, the expression level of OsZHD2 was significantly higher in the basal parts of shoots including the SAM compared with upper parts of the shoots that contain leaf blades and sheathes . RNA in situ hybridization experiments revealed that OsZHD2 transcripts were abundant in the root tip regions . Several homeobox genes have been identified as key regulators of cell proliferation and specification at the early stages of embryogenesis in plants. Among 107 homeobox genes identified in the rice genome, the expression profiles from 93 members in different tissues during various developmental stages have been analyzed . The results of the analyses revealed that OsZHD2 is highly expressed in the SAM . To evaluate whether OsZHD2 induces meristem activity, we treated seedling plants with 10 µM EdU, a thymidine analog, for 2 h to visualize the S-phase cells that actively incorporate EdU into DNA . The assay results revealed that OsZHD2-D had a higher number of S-phase cells in the RAM compared with the number of cells in the WT . The RAM region is defined based on the number of cells in a file that extend from the quiescent center to the first elongated cell . Quantifying such epidermis cells in the meristem region of lateral roots revealed that the number increased significantly in the activation line—25 versus 15 for the WT —which suggested that enhanced OsZHD2 expression led to the elongation of the RAM region.To confirm that the phenotypes observed from OsZHD2-D were due to the elevated expression levels of OsZHD2, we generated transgenic plants that expressed full-length OsZHD2 cDNA under the control of the maize Ubi promoter . From six independently transformed plants, we selected two lines, OX2 and OX4, which expressed OsZHD2 at high levels . Both had more extensive root systems compared with those of the out segregated WT . Their seminal roots and lateral roots were also significantly longer , and the plants had more lateral roots than the WT . However, the density of lateral roots did not vary among genotypes .

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Hydroponics Unveiled: A Deep Dive into Modern Agriculture Techniques

Interestingly, in companion cells of the phloem, AVP1 was also shown to be localized to the plasma membrane and function as a PPi synthase that contribute to phloem loading, photosynthate partitioning, and energy metabolism. On the other hand, AVP1 is also believed to contribute to the establishment of electrochemical potential across the vacuole membrane, which is important for subsequent vacuolar secondary transport and ion sequestration. Constitutive over expression of AVP1 improves the growth and yield of diverse transgenic plants under various abiotic stress conditions—including drought, salinity, as well as phosphorus and nitrogen deficiency—although the mechanism remains to be fully understood. Taken together, AVP1 serves as a multi-functional protein involved a variety of physiological processes in plants, some of which await to be fully understood. Magnesium is an essential macro-nutrient for plant growth and development, functioning in numerous biological processes and cellular functions, including chlorophyll biosynthesis and carbon fixation. Either deficiency or excess of Mg in the soil could be detrimental to plant growth and therefore plants have evolved multiple adaptive mechanisms to maintain cellular Mg concentration within an optimal range. In higher plants, the most well-documented Mg2+ transporters belong to homologues of bacterial CorA super family and are also called “MRS2” based on their similarity to yeast Mitocondrial RNA splicing 2 protein. Several members of the MGT family mediate Mg2+ transport in bacteria or yeast as indicated by functional complementation as well as 63Ni tracer assay . In plants, they have been shown to play vital roles in Mg2+ uptake, translocation,square planter pots and homeostasis associated with their different subcellular localizations and diverse tissue-specific expression patterns. For instance, MGT2 and MGT3 are tonoplast localized and possibly involved in

Mg2+ partitioning into mesophyll vacuoles; MGT4, MGT5, and MGT9 are strongly expressed in mature anthers and play a crucial role in pollen development and male fertility. MGT6 and MGT7 are shown to be most directly involved in Mg homeostasis because knocking-down or knocking-out either of the genes leads to hypersensitivity to low Mg conditions. MGT6 encodes a plasma membrane-localized high-affinity Mg2+ transporter and mediates Mg2+ uptake in root hairs, particularly under Mg-limited conditions . MGT7 is also preferentially expressed in roots and loss-of-function of MGT7 caused poor seed germination and severe growth retardation under low-Mg conditions. Double mutant of mgt6 and mgt7 displayed a stronger phenotype than single mutants, suggesting that MGT6 and MGT7 may be synergistic in controlling Mg homeostasis in low-Mg environment conditions. In contrast to considerable research on Mg transport and homeostasis under Mg deficient conditions, the regulatory mechanisms required for adaptation to excessive external Mg remain poorly understood. Recent studies suggested that MGT6 and MGT7 are essential for plants to adapt to both normal and high Mg conditions. The mgt6 mutant displayed dramatic growth defects with a decrease in cellular Mg content in the shoot, when grown under high Mg2+. Grafting experiments further suggested a shoot-based mechanism for Mg2+ detoxification although the exact role of MGT6 in this process is still not clear. More importantly, a core regulatory pathway consisting of two calcineurin B-like Ca sensors partnering with four CBL-interacting protein kinases has been established that allows plant cells to sequester Mg2+ into plant vacuoles, thereby protecting plant cells from high Mg2+ toxicity. In this study, we identified the tonoplast pyrophosphatase, AVP1, as an important component in high Mg2+ tolerance in Arabidopsis. Furthermore, by analyzing the avp1-4 mgt6 double mutant and avp1-4 cbl2 cbl3 triple mutant, we showed that the role of AVP1 in high-Mg tolerance was independent of previously reported MGT6 or CBL/CIPK-mediated pathway. Instead, our results suggested a novel link between high Mg2+ stress and PPi homeostasis in plants. Reducing the PPi concentration in the cytoplasm and increasing the acidification of vacuoles represent the two main biochemical functions of AVP1.

In order to dissect if both activities are required in this specific high Mg2+-associated process, we resorted to the transgenic line expressing yeast IPP1 gene under the control of the AVP1 promoter in the fugu5-1 mutant background. IPP1 is a cytosolic soluble protein which is not capable of translocating H+ , thus decoupling the hydrolysis and proton pump activities. Interestingly, our results showed that the severely retarded growth of fugu5-1 mutant plants under high-Mg conditions was completely recovered by expression of the IPP1 gene . The quantitative analysis of seedling fresh weight confirmed the complementation . To extend the phenotypic analysis of the avp1 mutants in mature plants, we examined the phenotype of avp1 mutants using hydroponic culture system. Consistent with the patterns of plant growth on agar plates, the mutant plants exhibited a pronounced growth defect than wild-type plants in the hydroponic solutions supplemented with 15 mM external Mg2+, as revealed by much lower fresh weight and lower chlorophyll content . The IPP1 transgenic line also behaved like wild-type plants but not avp1 mutant under this condition, suggesting that PPi hydrolysis is the key function that AVP1 plays in high-Mg adaptation. Although Mg is an essential macro-nutrient required for plant growth, high concentrations of environmental Mg2+ could be detrimental, and the targets underlying toxic effect of high-Mg are not well understood. In the present study, we characterized multiple avp1 mutant alleles and found they were hypersensitive to high external Mg2+. This finding has not only improved our understanding of the mechanism underlying Mg2+ tolerance but also uncovered a novel physiological function of AVP1 in plants. When the plants were confronted with high Mg stress, sequestration of excessive Mg2+ into the vacuole plays a vital role in detoxification of Mg excess from the cytoplasm . The AVP1 protein predominantly localized in the vacuolar membrane and was a highly abundant component of the tonoplast proteome. Encoded by AVP1, vacuolar H+ -PPase, together with vacuolar H+ -ATPase, plays a critical part in establishing the electrochemical potential by pumping H+ across the vacuolar membrane. This proton gradient, in turn, facilitates secondary fluxes of ions and molecules across the tonoplast. Based on this well-established idea, we hypothesized that avp1 mutants may be impaired in cellular ionic homeostasis and should thus exhibit hypersensitivity to a broad range of ions.

However, unexpectedly, we found that avp1 was hypersensitive only to high external Mg2+ but not to other cations . It was shown that over expression of AVP1 improved plant salt tolerance in quite a few species, which was interpreted as the result of increased sequestration of Na+ into the vacuole. It is thus reasonable to speculate that the tonoplast electrochemical potential generated by AVP1 would likewise favor Mg2+ transport into vacuoles via secondary Mg2+/H+ antiporter. Surprisingly, our subsequent experiments did not support this hypothesis and several lines of evidence suggested that the hypersensitivity of avp1 to high Mg2+ was not due to the compromised Mg2+ homeostasis in the mutant. First, unlike other high Mg2+-sensitive mutants such as mgt6 and the vacuolar cbl/cipk mutants, the Mg and Ca content in the avp1 mutant was not altered as compared with wild type, suggesting that AVP1 may not be directly involved in Mg2+ transport in plant cells. Second, higher order mutants of the avp1-4 mgt6 double mutant and avp1-4 cbl2 cbl3 triple mutant displayed a dramatic enhancement in Mg2+ sensitivity as compared to single mutants. These genetic data strongly suggest that AVP1 does not function in the same pathway mediated by MGT6 and does not serve as a target for vacuolar CBL-CIPK. Moreover,blueberry grow it was previously shown that either vacuolar H+ -ATPase double mutant vha-a2 vha-a3 or the mhx1 mutant defective in the proposed Mg2+/H+ antiporter was not hypersensitive to high Mg2+. These results implicate the vacuolar Mg2+ compartmentalization should be fulfilled by an unknown Mg2+ transporter/channel, whose activity is largely not dependent on the tonoplast ∆pH. Identification of this novel Mg2+ transport system across the tonoplast, which is probably targeted by vacuolar CBL-CIPK complexes, would be the key to understand the mechanism. Third, expression of the cytosolic soluble pyrophosphatase isoform IPP1 could fully rescue the Mg-hypersensitivity caused by AVP1 mutation. These lines of evidence pinpoint PPi hydrolysis, rather than ∆pH-assisted secondary ion transport and sequestration, as the major function of AVP1 in high Mg2+ adaptation. Under high Mg stress conditions, a number of adaptive responses are supposed to take place in plants, including the remodeling of plant morphogenesis as well as reprogramming of the gene expression and metabolite profile. However, very little is known so far and therefore, the molecular components targeted by excessive Mg2+ in plant cells remain obscure. Here, we suggest that the concentration of cellular PPi could be responsive to external Mg supply. Our results showed that extremely high levels of Mg2+ led to inhibition of the PPase activity in Arabidopsis, which in turn, resulted in the elevation of PPi content in the cytosol. Because high level of PPi is very toxic, the efficient removal of PPi by AVP1 under high Mg2+ conditions might become one of the limiting factors for optimal plant growth. This idea is supported by the observation that avp1 mutants accumulated significantly higher PPi content under high Mg2+ conditions compared with normal conditions . Most importantly, heterologous expression of the soluble PPase IPP1 gene rescued high Mg-sensitive phenotype of fugu5-1 , which strongly suggested that high Mg2+ hypersensitivity phenotype in avp1 mutants could primarily be attributed to impaired PPi homeostasis.It would be interesting to investigate how PPi concentrations vary in different Mg2+ conditions and during different plant growth stages.

Recently, cytosolic soluble pyrophosphatases were identified in Arabidopsis, and were shown to physiologically cooperate with the vacuolar H+ -PPase in regulating cytosolic PPi levels. Future studies should clarify if this type of soluble isoenzymes is also involved in the same high-Mg adaptation process. Collectively, our findings provide genetic and physiological evidence that AVP1 is a new component required for plant growth under high external Mg2+ concentrations and functions in regulating Mg2+ tolerance via PPi hydrolysis. For on-plate growth assays, seeds of different genotypes were sterilized with 75% ethanol for 10 min, washed in sterilized water for three times, and sown on Murashige and Skoog medium containing 2% sucrose and solidified with 0.8% phytoblend . The plates were incubated at 4 ◦C in darkness for two days and then were positioned vertically at 22 ◦C in growth chamber with a 14 h light/10 h dark photoperiod. After germination, five-day-old seedlings were transferred onto agarose-solidified media containing various ions as indicated in the figure legends and were grown under 14 h light/10 h dark photoperiod. For phenotypic assay in the hydroponics, 10-day-old seedlings geminated on MS plate were transferred to 1/6 strength MS solution and were grown under the 14 h light/10 h dark condition in the plant growth chamber. Fresh liquid solutions were replaced once a week. After two-week culture, the plants were treated with 1/6 MS solutions supplemented with 15 mM MgCl2. The majority of the current production, use, and disposal of engineered nanomaterials occur in terrestrial environments, and consequently terrestrial ecosystems are and will increasingly be some of the largest receptors of ENMs at all stages of their life cycles. In particular, soil is predicted to be one of the major receptors of ENMs due to ENM-contaminated bio-solid fertilizer and nanopesticide application to agricultural fields, runoff from landfills or ENM-bearing paints, or atmospheric deposition. Both agricultural and natural systems are at risk to ENM contamination via these release scenarios, which makes it necessary to understand the interactions between ENMs, soils, and soil organisms such as plants in order to predict their impacts in real-world scenarios. Gravity-driven vertical transport of TiO2, CeO2, and Cu2 engineered nanomaterials and their effects on soil pH and nutrient release were measured in three unsaturated soils. ENM transport was found to be highly limited in natural soils collected from farmland and grasslands, with the majority of particles being retained in the upper 0-3 cm of the soil profile, while greater transport depth was seen in a commercial potting soil. Physical straining appeared to be the primary mechanism of retention in natural soils as ENMs immediately formed micron-scale aggregates, which was exacerbated by coating particles with Suwannee River natural organic matter . Changes in soil pH were observed in natural soils contaminated with ENMs that were largely independent of ENM type and concentration. These changes may have been due to enhanced release of naturally present pH-altering ions in the soil, likely via substitution processes. This suggests ENMs will likely be highly retained near source zones in soil and may impact local communities sensitive to changes in pH or nutrient availability.

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Harvesting the Future: Hydroponic Agriculture and Global Food Security

Although this coating may not persist on the particles in the environment, what is clear is that the effects of chronic dosing and the effects of coating are critical data gaps that should be evaluated. Also completely lacking are more environmentally realistic exposure scenarios, such as ones using natural waters and soils and also multi-species microcosm or mesocosm studies, although such studies are underway. These studies will bring the importance of environmental transformations and indirect ecological impacts into light. It is possible that community or ecosystem level impacts may be more sensitive than individual level effects. Also more chronic and food chain transfer studies should be encouraged to deal with the possible long term effects from, or accumulations of, the likely persistent nanoceria entities. The current available data do not suggest an immediate risk from acute exposures to nanoceria from use as a fuel additive or mechanical/chemical polishing or planarization. However, the data gaps we have discussed should be addressed before a comprehensive ecological risk assessment can be performed for ceria for chronic exposures or for other exposure pathways. This review lays the foundation for such assessments and clearly identifies the areas where research is most critically needed.The Bioremediation, Education, Science and Technology partnership provides a sustainable and contemporary approach to developing new bio-remedial technologies for U. S. Department of Defense priority contaminants while increasing the representation of underrepresented minorities and women in an exciting new bio-technical field. This comprehensive and innovative bio-remediation education program provides under-represented groups with a cross-disciplinary bio-remediation curriculum and financial support, coupled with relevant training experiences at advanced research laboratories and field sites. These programs are designed to provide a stream of highly trained minority and women professionals to meet national environmental needs. The BEST partnership of institutions and participants benefit from a unique central strategy— shared resources across institutional boundaries.

By integrating diffuse resources, BEST forms a specialized “learning institution without walls,” large plastic pots for plants where participants can receive advanced training at any BEST site, and where research capabilities flow freely among the participating institutions. Ongoing faculty and student exchange programs, video taped lectures, the Rotating Scholars program, and the BEST web-site ensure that all participants are empowered with opportunities to excel. The BEST partnership consists of Lawrence Berkeley National Laboratory in Berkeley, Calif., Jackson State University in Jackson, Miss., Ana G. Méndez University System in Puerto Rico, University of Texas at El Paso , University of Southern Mississippi Gulf Coast Research Lab, and University of California at Berkeley . The BEST program contract to the partnership is man-aged by LBNL for the Army Corps of Engineers, Waterways Experiment Station in Vicksburg, Miss. WES manages the contract for the Army Corps of Engineers and is the contracting entity for DoD. The partnership formed by these participating institutions leverages existing institutional resources by strengthening intramural bio-remediation education and research capabilities, and through outreach pro-grams, to disseminate training and scientific enhancement to other Historically Black Colleges and Universities and Minority Institutions . The BEST institutions are focal points for the development and dissemination of cutting-edge research and technology for the bio-remediation of nitro-aro-matic compounds, polycyclic aromatic hydrocarbons and toxic metals. The multidisciplinary BEST partnership strategy creates a flask-to-field solution that develops laboratory research into technology, and technology into field-scale environmental applications required for the cost-effective restoration of damaged environments. This year saw the addition of the University of Southern Mississippi’s Gulf Coast Research Lab and the University of Texas at El Paso as partners in the BEST program. Both institutions provide significant new personnel and training opportunities for the BEST program. The USM Gulf Coast Research Lab investigators’ focus on PAH and heavy metal phytoremediation along shorelines provides an exciting new focus with increased field opportunities for students. The UTEP investigators are focusing on exciting new metal phy-toremediation techniques using desert plants and exciting new techniques to determine risk assessment with PAHs. This year also saw the passage of the program director-ship at LBNL from Dr. Jenny Hunter-Cevera to Dr. Terry C. Hazen in October 1999. Dr. Hunter-Cevera, who has managed the BEST program at LBNL since its inception, will be sorely missed, but her new position as president of the Maryland Biotechnology Institutes may provide increased opportunities for collaboration for the entire BEST program. Dr. Hazen, who specializes in bio-remediation field applications, has demonstrated or deployed bio-remediation technologies at more than 50 sites around the United States and in Europe. He has five patents in bio-remediation technologies that are licensed by more than 40 companies in the U.S. and Europe.

During the past year, the BEST program has provided minority research training for five high school students, 74 undergraduates, 32 graduate students, three post-doctoral fellows and 10 faculty. Students and fac-ulty investigators have given 43 presentations on BEST research at scientific meetings and have published 17 scientific papers. The program produced a full color brochure and flyers in 1999 for use in recruiting more students, and also sponsored 32 lecture/seminars on bio-remediation. Fourteen videotapes of BEST seminars at LBNL/UCB were distributed to the partner institutions. The BEST program also sponsored a phytoremediation workshop for BEST investigators and students that was attended by more than 60 participants. Additional workshops are planned for the coming year. In this report, the research is organized by subject area, and two-page briefs are presented for each of 28 BEST projects. The projects presented provide a good representation of the state-of-the-science research being done with students in the BEST program – the best of BEST.Over the next 75 years, the U.S. government will undertake what has been called the largest civil works project in world history to restore the environment damaged by previous activities at federal sites, e.g., Department of Defense military bases and Department of Energy nuclear facilities. Legislative action, resulting from concern over the accumulating hazards, has mandated pollution control measures and environmental restoration of hazardous waste at all sites. Estimates of total cleanup costs range from $230 billion to more than half a trillion dollars. Given the trend of diminishing budgets throughout the federal government, future generations could inherit both an environmental and budgetary disaster. The imprecision of the cost estimates results from the lack of knowledge of how “clean” the contaminated sites will need to be. Some of the environmental damage is permanent—cleanup technologies either do not exist or are incapable of remediating the contamination. For DoD bases being closed by the Base Realignment and Closure Program, all toxic sites must be remediated before the site is returned to public use. The projected costs of site restoration using existing technologies are staggering: the estimated cleanup cost is at least $24.5 billion for the 7,313 identified U.S. sites . The pollutants at these sites include chlorinated hydrocarbons, metals, petroleum products, explosives, mixed waste and other organics. DOE also has substantial remediation costs—estimated to be from $90 billion to $200 billion . The domestic private sector presents yet another huge set of remediation problems, dwarfed only by the international problems in Eastern Europe and Russia . There is clearly a need for new cost-effective treatment technologies. Bio-remediation, the use of microor-ganisms to detoxify hazardous waste, promises to provide economical and ecologically sound clean-up strategies. An Office of Technology Assessment analysis concluded that the U.S. does not possess a sufficient pool of qualified environmental professionals, i.e.,blueberry pot the trained scientific personnel required to support this rapidly developing multi-disciplinary field. In response to these national environmental needs, the Bio-remediation Education, Science and Technology Program, funded by DoD, was established in 1996. In a few short years, BEST has pioneered a new and successful model for environmental science and education. This partnership has a highly integrated programmatic focus on the scientific and workforce needs of DoD. Since the inception of the BEST program, a significant number of major milestones and deliverables have been achieved. They are described below. The BEST program has made these dramatic accomplishments by using an approach that combines a training-education element with an integrated research project, described later in this introduction.DoD sites throughout the United States contain highly contaminated soils, groundwater and sediments. These properties pose direct and indirect exposure hazards to humans and wildlife.

Conventional remedial solutions for contaminated soils and sediments or groundwater are slow and expensive, increase inputs to hazardous waste disposal sites, and can increase human exposure to contaminants. Bio-remediation — the use of microo ganisms to destroy hazardous contaminants or to con-vert them to harmless forms — is an emerging treatment technology that can in many instances restore contaminated environments more quickly, at lower cost and at lower human risk than alternative remediation technologies. Bio-remediation can operate in either an in situ mode where contaminants are treated in place, or in an ex situ mode where contaminants are removed from a contaminated zone for treatment . In situ bio-remediation can be used when excavation is impractical — under buildings, highways, runways, etc. In situ bio-remediation can simultaneously treat soil and groundwater in one step, without the generation of hazardous waste products. In situ contaminant degradation can be achieved by either intrinsic or enhanced bio-remediation. Intrinsic bio-remediation exploits the innate capabilities of indigenous micro-bial communities to degrade pollutants. Enhanced bio-remediation seeks to accelerate in situ microbial activity by isolating and controlling the contaminated site so that the microbial environment can be purposely manipulated to correct nutritional or gas phase limitations. Ex situ treatment seeks to further control the remedial environment by placing the contaminants in an engineered treatment system. Phytore mediation, a process in which plants and asso-ciated microbial communities are used for contaminant bio-degradation or bio-immobilization, is an important and rapidly developing mode of bio-remediation. To realize the full potential benefits of plant and microbial treatment systems at DoD sites, these bio-technologies must be developed and optimized for remediation of DoD priority contaminants by an expanded pool of qualified professionals. It was in response to these DoD environmental needs that the BEST partnership of institutions was established.In order to determine whether plants can stimulate the degradation of PAHs in soil, plant species found in literature on phytoremediation of metal-contaminated sites were selected to measure the removal of PAHs in artificially contaminated soil over a period of 62 days. The plant species used for this experiment were alfalfa , barley , tall fescue and orchard grass . The PAHs were phenanthrene and anthracene, in a mixture of 600 ppm each. As shown in Figures 1 and 2, phenanthrene and anthracene were removed from the soils with plants after 62 days. More than 98% of the phenanthrene was removed during that period while the anthracene removal was found to be between 70 and 90%. The results suggest that the rate of disappearance of phenanthrene in soil was greater than anthracene under the same conditions. From the results, it is also indicated that the disappearance of PAHs in soil depends on the bio-availability of the compounds. Because phenanthrene is approximately 10 times more soluble in water than anthracene, it was expected to be more readily available to microbial degradation than anthracene. Plant-assisted degradation of PAHs is thought to be more effective on PAHs with a higher number of rings and higher molecular weights, such as benzopyrene. Anthracene removal in the soil planted with alfalfa was greater than in the soil without plants, while all the other plants have minimal to no effect on anthracene removal compared to the control soil. Phenanthrene was removed to a greater extent in the soil with alfalfa and tall fescue compared to the control without plants . However, both barley and orchard grass showed no effects of the removal of phenanthrene during that period when compared to the soil without plants. Overall, plants had minimum effect on phenanthrene degradation while anthracene degradation was more dependent on plant species. In order to determine the effect of PAH degradation by plants on bacterial numbers in soil, bacteria were counted in soil during the course of the experiment.Parathion is a widely used organophosphate insecticide which can cause adverse neurological effects if ingested or after dermal exposure. No single microor-ganism has been isolated that is capable of completely mineralizing parathion and its metabolites. Hydrolysis of parathion significantly lowers the toxicity of the parent compound, but results in the formation of a toxic intermediate, the nitroaromatic compound p-nitrophenol.

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Hydroponic Agriculture: Cultivating the Future of Sustainable Farming

Interestingly, suppression of endodermal ABA signalling seems to contribute to the inactivation of aquaporin-mediated Lpr in a wild-type Scheduling low but frequent NO3 − applications, at-tuned to crop demand, allows the crop to take up most of the NO3 − before it passes through the low-salinity zone into the saline fringes. Figure 7 simulates continuous NO3 − application and a scenario which applies NO3 − only every 10 d, while the total amount of NO3 − applied is the same for both simulations. High-frequency applications of NO3 − using drip irrigation in-creased N uptake efficiency in some cases .Both Casparian strips and suberin lamellae, two extracellular hydrophobic barriers located in the wall of endodermal cells of the root, are thought to play important roles in restricting the free diffusion of solutes and water . Casparian strips act as apoplastic barriers not only to block solutes moving into the xylem through the free space between cells, but also to prevent their backfow from the stele to the apoplast of the cor-tex. Suberin lamellae, due to their deposition between the endodermal plasma membrane and secondary cell wall, do not block aploplastic transport but rather limit transcellular transport of nutrients and possibly water at the endodermis. Cross talk between the Casparian strip and suberin lamellae exists, with suberin being deposited in response to disruption of Casparian strips . Tese extracellular barriers are therefore at a cross-road between control of mineral nutrient and water uptake. However, the mechanisms that allow plants to integrate both these barrier functions to enable the simultaneous uptake of sufcient water and mineral nutrients remain under explored. Te dirigent-like protein Enhanced Suberin1 functions in the correct formation of Casparian strips by allowing the lignin, deposited at the Casparian Strip Domain through the action of Peroxidase64 and the Respiratory Burst Oxidase Homolog F ,blueberry packaging to form into a continuous ring. In the absence of this dirigent-like protein defective Casparian strips are formed along with enhanced and early deposition of suberin in the endodermis.

A similar pattern of Casparian strip disruption and response is also observed when the Casparian Strip Domain is disrupted through the loss of Casparian Strip Domain Proteins. Tese changes lead to systematic alterations in the profile of mineral nutrients and trace elements accumulating in leaves, and this phenotype provided the first tool for identification of genes involved in Casparian strip development. Detection of the diffusible vasculature-derived peptides CASPARIAN STRIP INTEGRITY FACTORS 1 & 2 through interaction with the SCHENGEN3 receptor-like kinase is what drives this endodermal response to loss of Casparian strip integrity. Here, we report that detection of a loss of Casparian strip integrity at the root endodermis by the CIFs/SGN3 pathway leads to an integrated local and long-distance response. This response rebalances water and mineral nutrient uptake, compensating for breakage of the Casparian strip apoplastic seal between the stele and the cor-tex. This rebalancing involves both a reduction in root hydraulic conductivity driven by deactivation of aquapor-ins, and limitation of ion leakage through deposition of suberin in endodermal cell walls. This local root-based response is also coupled to a reduction in water demand in the shoot driven by ABA-mediated stomatal closure.Te dirigent-like protein Enhanced Suberin1 functions in the formation of Casparian strips by allowing the correct deposition of lignin at the Casparian strip domain. Te enhanced deposition of suberin in the esb1-1 mutant with disrupted Casparian strips can clearly be observed using the lipophilic stain Fluorol Yellow 088 close to the root tip , and this can be quantified by counting the number of endodermal cells afer the onset of cell expansion to the first appearance of yellow fuorescence . This early deposition of suberin is also verifed by the clear correspondence of FY 088 staining with enhanced promoter activity of known suberin biosynthetic genes, including GPAT5 monitored through both GUS staining and GFP fuorescence , and also others through GUS staining . This is further reinforced by the enhanced expression of known suberin biosynthetic genes in esb1-1 relative to wild-type . To better understand the causal link between Casparian strip integrity and enhanced deposition of suberin, we performed a reciprocal grafing experiment that revealed that the esb1-1 mutation is only required in the root to drive enhanced deposition of suberin at the endodermis, placing the function of ESB1 and the driver for increased suberin in the same tissue .

To determine the cause and effect rela-tionship between damaged Casparian strips and enhanced suberin we carefully monitored the first appearance of both Casparian strips and enhanced suberin in esb1-1. Using lignin staining in the Casparian strip marker line pCASP1::CASP1::GFP, we are able to observe that damaged Casparian strips are visible 2.5 days afer sowing . This is at least 12hr before the first indication of enhanced suberin biosynthesis, which we monitor using promoter activity of suberin biosynthetic genes GPAT5, FAR4, FAR1 and FAR5 . This was also verified by the direct observation of suberin deposition with FY 088 . Te observation that treatment with the CIF2 peptide, normally leaked from the stele through loss of Casparian strip integrity, can enhance suberin deposition in wild-type plants supports our interpretation that enhanced suberin deposition is a response to loss of integrity of the Casparian strip-based apoplastic diffusion barrier. Furthermore, loss-of-function of the receptor-like kinase SGN3, required for sensing of CIFs, blocks the enhanced deposition of suberin in esb1-1 and casp1-1casp3-1 based on a chemical analysis of suberin in esb1-1 , and also on FY 088 staining. We conclude that Casparian strip defects sensed by the CIFs/SGN3 surveillance system lead to enhanced deposition of suberin in the endodermis.Te observation that enhanced suberin is deposited as a response to loss of integrity of the endodermal-based diffusion barrier between stele and cortex, raises the question, what is the function of this increased suberin deposition? Previously, the extent of endodermal suberin has been shown to be part of the response to nutrient status . We therefore tested the selectivity to solutes σNaCl, in roots varying in the extent of suberin deposition and the functionality of Casparian strips. For this, we measured solute leakage into xylem sap of pressurized roots at increasing sodium chloride concentrations in the solution bathing the roots. Taken individually, σNaCl of roots of esb1-1, sgn3-3 and wild-type were not significantly different from one another , which is surprising given the disruption of the Casparian strip-based apoplastic diffusion barrier in both mutants.

However, removal of suberin in esb1-1, by endodermal-specific ectopic expression of a cutinase ,blueberry packaging box caused a significant decrease in σNaCl compared to wild-type plants , and a similar tendency when compared to esb1-1 . This supports the notion that enhanced suberin deposition at the endodermis helps prevent passive solute leakage caused by defects in the Casparian strips of the esb1-1 mutant. We also observed a significant decrease in σNaCl in the double mutant esb1-1sgn3-3 compared to both wild-type and sgn3-3 . It is known that SGN3 is required for the enhanced deposition of suberin that occurs at the endodermis in esb1-1 . Our observation that removal of this enhanced suberin in esb1-1sgn3-3 decreases σNaCl further supports our conclusion that the role of this increased suberin deposition is to limit solute leakage where Casparian strip barriers are disrupted.It has also been suggested that endodermal suberin may impact water permeability, though how is still unclear. To further address the role of enhanced endodermal suberin, we investigated root hydraulic conductivity of esb1-1 and observed a significant reduction by 62% with respect to wild-type . Importantly, this difference in esb1-1 Lpr originates mainly from a reduction in an aquaporin-mediated water transport pathway . We also observed that the azide-resistant water transport pathway was lower in esb1-1 than in wild-type , yet to a lesser extent than the aquaporin mediated pathway. Te dra-matic reduction in aquaporin-mediated Lpr in esb1-1 we observe is an intriguing fnding, which led us to consider if this lack of aquaporin activity in esb1-1 roots is due to a direct output from the CIFs/SGN3 signalling pathway, or if it represents an efect downstream of enhanced suberin deposition. We found that removal of endodermal suberin in esb1-1 through expression of CDEF1 in the endodermis had no further efect on Lpr . This rules out a role for suberin in the reduced aquaporin-mediated Lpr of esb1-1. However, in the esb1-1sgn3-3 dou-ble mutant, as compared to esb1-1, we observed a full recovery of Lpr back to wild-type levels . Loss of Casparian strip integrity in esb1-1 therefore appears to be sensed by the CIFs/SGN3 signalling pathway, which leads to the inactivation of aquaporins, thereby reducing Lpr . To support this conclusion, we show that exogenous application of CIF2 to wild-type plants for 3h induces a reduction in Lpr, and only in the presence of a functional SGN3 . We have established the existence of two critical outputs of the CIFs/SGN3 diffusion-barrier surveillance system. Tese are enhanced deposition of endodermal suberin limiting solute leakage, and the inactivation of root aquaporin activity reducing Lpr. Do these two independent outputs of the CIFs/SGN3 diffusion barrier surveillance system work in parallel, or in series with one response leading to the other? Te fact that removal of endodermal suberin in esb1-1 does not compensate for its reduced Lpr suggests that enhanced suberin deposition is not the cause of the reduced aquaporin-mediated Lpr. However, reduced activity of aquaporins through loss-of-function of the two major aquaporins PIP2;1 and PIP2;2 in the pip2;1pip2;2 double mutant, does cause significant increases in endodermal suberin deposition . A similar increase in suberin is also observed afer treatment with the aquaporin inhibitor sodium azide through observation of the activity of the transcriptional reporter pGPAT5::mCITRINE-SYP122 for suberin biosynthesis. GPAT5 expression is observed to expand toward the root tip after 6 hours only of sodium azide treatment .

Based on this evidence, we propose the following sequence of events. Casparian strip defects are detected by the apoplastic leakage of CIFs from the stele, being sensed by SGN3. Once activated, SGN3 signals the inactivation of aqua-porins thereby reducing Lpr which in turn leads to the early and enhanced deposition of endodermal suberin. Insuch a model, SGN3 would inhibit aquaporin function, which may appear at variance with the usual activation of aquaporins through phosphorylation. Yet, such an inhibition was recently described in the case of FERONIA, a protein kinase inactivating PIP2; 1 function through an as yet unknown mechanism.Abscisic acid has been shown to be involved in regulating both aquaporin activity reviewed in and suberin deposition, making ABA an interesting can-didate worth exploring for a role in downstream CIFs/SGN3 signalling. To probe this possibility we expressed the dominant negative allele of the regulator of ABA signalling ABA-INSENSITIVE 1 in the endoder-mis of esb1-1 using pELTP::abi1. This abi1 construct specifically blocks ABA signalling at the endodermis and delays suberisation in a wild-type background as previously shown in . In esb1-1, we observed abi1 to have no effect on either the inactivation of aquaporins or the enhanced deposition suberin . We also observe that aquaporin inhibition with sodium azide in the pELTP::abi1-1 line still induces expression of the suberin biosynthesis gene GPAT5 toward the root tip in the pGPAT::mCITRINE-SYP122 line, as observed in wild-type . Based on this, activation of ABA signalling in the endodermis does not link perception of Casparian strip defects with the downstream responses of reduced aquaporin-mediated Lpr or suberin deposition. Suppbackground .The esb1-1 mutant is known to have reduced stomatal apertures and enhanced wilting resistance. This suggests that the CIFs/SGN3 sensing system not only initiates a local root response to Casparian strip integrity but is also involved in initiating long-distance responses in the shoot. We observe reduced stomatal apertures in esb1-1 , and an analysis of the expression of a set of known ABA signalling and response genes in leaves suggest that this stomatal closure is part of an ABA driven response. The aba1 mutation confers a strong ABA deficiency.By generating an esb1-1aba1 double mutant, we investigated the ABA-dependent component in the leaf response we observe in esb1-1. ABA-defciency in esb1-1aba1 suppressed both the reduced stomatal aperture and the activation of expression of ABA signalling and response genes that we observe in esb1-1 .