RESUMO
Cd-contaminated farmlands threaten food security and safety by inhibiting crop growth and Cd accumulating in edible parts. Phytoremediation is a promising option to remove Cd from farmland soil. An ideal option is to remediate Cd and produce crops simultaneously on the contaminated soil. Therefore, we chose widely planted oil crops (soybean, sunflower and rape) as experimental materials, cultured in pots filled with soils contaminated with different concentrations (10, 20, 50, and 100 mg kg-1) Cd till harvest, and then took a closed-loop method to evaluate the remediation potential of the three oil crops, including the remediating ability, yield, and quality of seeds and environmental risk of pyrolytic biochar. The results show that the order of Cd accumulation capacity in the three oil crops was sunflower > rape > soybean. The yield and quality of the three oil crops were decreased by being treated with different concentrations of Cd. In addition, the order for a decreased degree in yield of the three oil crops was sunflower < rape < soybean, and the order for a decreased degree in protein and fat content was sunflower < soybean < rape. The potential risk of seeds of the three oil crops as food/feed was sunflower/soybean < soybean/sunflower < rape. After pyrolysis of harvested three oil crops, the order for leaching toxicity/leaching potential was sunflower-biochar < soybean-biochar/rape-biochar < rape-biochar/soybean-biochar. All three oil crops could remediate Cd-contaminated soils, and their seeds could generate economic value. Closed-loop evaluation of sunflower proved it might be a good option for removing Cd from farmland soil.
Assuntos
Asteraceae , Helianthus , Metais Pesados , Poluentes do Solo , Asteraceae/metabolismo , Biodegradação Ambiental , Cádmio/análise , Carvão Vegetal , Produtos Agrícolas/metabolismo , Helianthus/metabolismo , Metais Pesados/análise , Solo , Poluentes do Solo/análiseRESUMO
MAIN CONCLUSION: Exogenous calcium enhances rice tolerance to acid rain stress by regulating isozymes composition and transcriptional expression of ascorbate peroxidase and glutathione reductase. Calcium (Ca) participates in signal transduction in plants under abiotic stress, and addition of Ca2+ is beneficial to alleviate damage of plants caused by acid rain. To clarify the effect of exogenous Ca2+ on tolerance of plants to acid rain stress, we investigated regulation of Ca2+ (5 mM) on activities, isozymes composition and transcriptional expression of ascorbate peroxidase (APX) and glutathione reductase (GR), redox state, and H2O2 concentration and growth in rice leaves and roots under simulated acid rain (SAR) stress. SAR (pH 3.5/2.5) decreased the total activities of APX and GR in rice by decreasing the concentration of APX isoforms (APXII in leaves and APXIII in roots) as well as activation degree of GR isozymes and transcription level of GR1, indicating that SAR (pH 3.5/2.5) destroyed the redox state in rice cells and induced H2O2 excessive accumulation, and inhibited growth of rice. Exogenous Ca2+ alleviated SAR-induced inhibition on activities of APX and GR by regulating the concentration, activation, and transcription of their isozymes, and then maintained the redox level of cells and protected cells from oxidative damage, being beneficial to the growth of rice. Therefore, the promotion of exogenous Ca2+ on activities of APX and GR can be important to enhance rice tolerance to acid rain by maintaining redox state and avoiding oxidative damage.
Assuntos
Chuva Ácida , Oryza , Chuva Ácida/efeitos adversos , Antioxidantes , Ascorbato Peroxidases/metabolismo , Cálcio , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio , Oryza/genética , Oryza/metabolismo , Estresse Oxidativo , Plântula/metabolismoRESUMO
Microcystins (MCs) have become an important global environmental issue, causing oxidative stress, which is an important toxic mechanism for MCs in plants. However, the regulating mechanism of antioxidative enzymes in plants in adapting to MCs stress remains unclear. We studied the dynamic effects of MCs at different concentrations (5, 10, 50 and 100 µg/L) in rice and cucumber seedlings on relative growth rate (RGR), and reactive oxygen species and malondialdehyde (MDA) content, and antioxidative enzyme activities, during a stress period (MCs exposed for 1, 3, 5 and 7 d) and recovery period (7 d). During the stress period, MCs at 5 µg/L inhibited RGR in cucumber and promoted RGR in rice. The contents of superoxide anion (O2·-), hydrogen peroxide (H2O2) and MDA increased and RGR declined in both crops with time and intensity of MCs stress. For cucumber, all these parameters responded earlier to MCs stress, and O2·-, MDA and RGR were more responsive to MCs stress than in rice. Moreover, catalase (CAT) and peroxidase (POD), and the relative expressions of CAT genes increased in both crops at 5-100 µg/L MCs, whereas relative expression of POD genes increased only in cucumber. Diversely, superoxide dismutase (SOD) response to MCs in cucumber leaves was later than for rice. MCs at 100 µg/L decreased the relative expression of SOD genes in cucumber but did not change SOD activity. During the recovery period, all the above indicators in both crops were higher than the control and lower than in the stress period. Conversely, RGR was lower than in the control and higher than in the stress period, except for cucumber which was lower, and MDA content higher than the stress period at 100 µg/L MCs. Overall, these results indicated that cucumber was more sensitive to MCs than rice, and SOD, CAT and POD play an important role in plant response to MCs stress.
Assuntos
Cucumis sativus/efeitos dos fármacos , Microcistinas/toxicidade , Oryza/efeitos dos fármacos , Antioxidantes/metabolismo , Catalase/genética , Catalase/metabolismo , Cucumis sativus/enzimologia , Cucumis sativus/genética , Cucumis sativus/crescimento & desenvolvimento , Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Oryza/enzimologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Estresse Oxidativo , Peroxidase/genética , Peroxidase/metabolismo , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/genética , Plântula/metabolismo , Superóxido Dismutase/metabolismo , Superóxidos/metabolismoRESUMO
MAIN CONCLUSION: Application of proper ABA can improve acid tolerance of rice roots by balancing endogenous hormones and promoting nutrient uptake. Abscisic acid (ABA) has an important signaling role in enhancing plant tolerance to environmental stress. To alleviate the inhibition on plant growth and productivity caused by acid rain, it is crucial to clarify the regulating mechanism of ABA on adaptation of plants to acid rain. Here, we studied the effects of exogenously applied ABA on nutrients uptake of rice roots under simulated acid rain (SAR) stress from physiological, biochemical and molecular aspects. Compared to the single SAR treatment (pH 4.5 or 3.5), exogenous 10 µM ABA alleviated the SAR-induced inhibition of root growth by balancing endogenous hormones (abscisic acid, indole-3-acetic acid, gibberellic acid and zeatin), promoting nutrient uptake (nitrate, P, K and Mg) in rice roots, and increasing the activity of the plasma membrane H+-ATPase by up-regulating expression levels of genes (OSA2, OSA4, OSA9 and OSA10). However, exogenous 100 µM ABA exacerbated the SAR-caused inhibition of root growth by disrupting the balance of endogenous hormones, and inhibiting nutrient uptake (nitrate, P, K, Ca and Mg) through decreasing the activity of the plasma membrane H+-ATPase. These results indicate that proper concentration of exogenous ABA could enhance tolerance of rice roots to SAR stress by promoting nutrients uptake and balancing endogenous hormones.
Assuntos
Ácido Abscísico/farmacologia , Chuva Ácida/efeitos adversos , Oryza/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Raízes de Plantas/efeitos dos fármacos , Ácido Abscísico/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Oryza/anatomia & histologia , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Zeatina/metabolismoRESUMO
Calcium (Ca) is one of essential elements for plant growth and development, and also plays a role in regulating plant cell physiology and cellular response to the environment. Here, we studied whether calcium played a role in enhancing tolerance of plants to acid rain stress by hydroponics and simulating acid rain stress. Our results show that acid rain (pH 4.5/pH 3.0) caused decreases in dry weight biomass, chlorophyll content and uptake of nutrients elements (NO3-, P, K, Mg, Zn and Mo) and an increase in membrane permeability of root. However, all parameters in soybean treated with exogenous calcium (5â¯mM) and acid rain at pH 4.5 were closed to the control levels. In addition, exogenous calcium (5â¯mM) alleviated the inhibition induced by pH 3.0 acid rain on the activity of plasma membranes H+-ATPase and the expression of GmPHA1 at transcriptional level, being benefiting to maintaining uptake of nutrients (NO3-, P, K, Mg, and Zn), and then lower the decrease in dry weight biomass and chlorophyll content. After a 5-day recovery (without acid rain stress), all parameters in soybean treated with acid rain at pH 3.0 and exogenous calcium were still worse than those of the control, but obviously better than those treated with acid rain at pH 3.0. Higher activity of plasma membrane H+-ATPase in soybean treated with acid rain at pH 3.0 and exogenous calcium was good to uptake of nutrients and promoted the recovery of soybean growth, compared with soybean treated with acid rain at pH 3.0. In conclusion, exogenous calcium could alleviate the inhibition caused by acid rain on soybean growth by increasing the activity of plasma membrane H+-ATPase for providing driving force to nutrient absorption, and its regulating effect was limited by intensity of acid rain. Furthermore, the application of exogenous calcium can be one of ways to alleviate the damage caused by acid rain to plants.
Assuntos
Chuva Ácida/toxicidade , ATPases Transportadoras de Cálcio/metabolismo , Cálcio/farmacologia , Glycine max/efeitos dos fármacos , Glycine max/fisiologia , ATPases Translocadoras de Prótons/metabolismo , Transporte Biológico , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Clorofila/metabolismo , Magnésio/metabolismo , Molibdênio/metabolismo , Nitratos/metabolismo , Fósforo/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/fisiologia , Potássio/metabolismo , ATPases Translocadoras de Prótons/genética , Plântula/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacos , Zinco/metabolismoRESUMO
The growing number of biotech crops with novel genetic elements increasingly complicates the detection of genetically modified organisms (GMOs) in food and feed samples using conventional screening methods. Unauthorized GMOs (UGMOs) in food and feed are currently identified through combining GMO element screening with sequencing the DNA flanking these elements. In this study, a specific and sensitive qPCR assay was developed for vip3A element detection based on the vip3Aa20 coding sequences of the recently marketed MIR162 maize and COT102 cotton. Furthermore, SiteFinding-PCR in combination with Sanger, Illumina or Pacific BioSciences (PacBio) sequencing was performed targeting the flanking DNA of the vip3Aa20 element in MIR162. De novo assembly and Basic Local Alignment Search Tool searches were used to mimic UGMO identification. PacBio data resulted in relatively long contigs in the upstream (1,326 nucleotides (nt); 95 % identity) and downstream (1,135 nt; 92 % identity) regions, whereas Illumina data resulted in two smaller contigs of 858 and 1,038 nt with higher sequence identity (>99 % identity). Both approaches outperformed Sanger sequencing, underlining the potential for next-generation sequencing in UGMO identification.
Assuntos
Agricultura/legislação & jurisprudência , Proteínas de Bactérias/genética , Gossypium/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Plantas Geneticamente Modificadas/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Zea mays/genética , Contaminação de Alimentos/legislação & jurisprudênciaRESUMO
Microcystins (MCs) are the most widespread and hazardous cyanotoxins posing a huge threat to agro-ecosystem by irrigation. Some adaptive metabolisms can be initiated at the cellular and molecular levels of plant to survive environmental change. To find ways to improve plant tolerance to MCs after recognizing adaptive mechanism in plant, we studied effects of MCs on root morphology, mineral element contents, root activity, H+-ATPase activity, and its gene expression level in cucumber during exposure and recovery (without MCs) periods. After being exposed to MCs (1, 10, 100 and 1000 µg L-1) for 7 days, we found 1 µg L-1 MCs did not affect growth and mineral elements in cucumber. MCs at 10 µg ·L-1 increased root activity and H+-ATPase activity partly from upregulation of genes (CsHA2, CsHA3, CsHA8, and CsHA9) expression, to promote nutrient uptake. Then, the increase in NO3-, Fe, Zn, and Mn contents could contribute to maintaining root growth and morphology. Higher concentration MCs (100 or 1000 µg L-1) inhibited root activity and H+-ATPase activity by downregulating expression of genes (CsHA2, CsHA3, CsHA4, CsHA8, CsHA9, and CsHA10), decreased contents of nutrient elements except Ca largely, and caused root growing worse. After a recovery, the absorption activity and H+-ATPase activity in cucumber treated with10 µg L-1 MCs were closed to the control whereas all parameters in cucumber treated 1000 µg L-1 MCs were even worse. All results indicate that the increase in H+-ATPase activity can enhance cucumber tolerance to MC stress by regulating nutrient uptake, especially when the MCs occur at low concentrations.
Assuntos
Cucumis sativus , Microcistinas/metabolismo , Ecossistema , ATPases Translocadoras de Prótons/metabolismo , Membrana Celular/metabolismo , Minerais/metabolismo , Raízes de Plantas/metabolismoRESUMO
Single-atom catalysts (SACs), with precisely controlled metal atom distribution and adjustable coordination architecture, have gained intensive concerns as efficient oxygen reduction reaction (ORR) electrocatalysts in Zn-air batteries (ZAB). The attainment of a monodispersed state for metallic atoms anchored on the carbonaceous substrate remains the foremost research priority; however, the persistent challenges lie in the relatively weak metal-support interactions and the instability of captured single atom active sites. Furthermore, in order to achieve rapid transport of O2 and other reactive substances within the carbon matrix, manufacturing SACs based on multi-stage porous carbon substrates is highly anticipated. Here, we propose a methodology for the fabrication of carbon aerogels (CA)-supported SACs utilizing papermaking nanofibers, which incorporates advanced strategies for N-atom self-doping, defect/vacancy introduction, and single-atom interface engineering. Specifically, taking advantages of using green and energy-efficient feedstocks, combining with a direct pore-forming template volatilization and chemical vapor deposition approach, we successfully developed N-doped carbon aerogels immobilized with separated iron sites (Fe-SAC@N/CA-Cd). The obtained Fe-SAC@N/CA-Cd exhibited substantially large specific surface area (SBET = 1173 m2/g) and a multi-level pore structure, which can effectively mitigate the random aggregation of Fe atoms during pyrolysis. As a result, it demonstrated appreciable activity and stability in catalyzing the ORR progress (E1/2 = 0.88 V, Eonset = 0.96 V). Furthermore, the assembled liquid electrolyte-state Zn-air batteries (LES-ZAB) and all-solid-state Zn-air battery (ASS-ZAB) also provides encouraging performance, with a peak power density of 169 mW cm-2 for LES-ZAB and a maximum power density of 124 mW cm-2 for ASS-ZAB.
RESUMO
Acid rain threatens crop yield and nutritional quality, and Ca2+ can regulate plant responses to abiotic stresses. To improve the yield and nutritional quality of crops under acid rain stress, we applied exogenous Ca2+ to regulate nitrogen assimilation in rice seedlings under simulated acid rain stress (pH 4.5 or 3.0), taking yield and nutritional quality of rice as evaluation criteria. We found that Ca2+ (5 mM) maintained the total nitrogen content of rice at the seedling and booting stages to alleviate the inhibitory effect of simulated acid rain on rice yield. Meanwhile, Ca2+ improved the activity of glutamate synthase to eliminate the disruption of glutamine synthetase/glutamate synthase balance under simulated acid rain. It decreased the efficiency of nitrogen assimilation, thereby reducing the inhibition of essential amino acid content in rice. The mitigation effect on simulated acid rain at pH 4.5 was better than that of simulated acid rain at pH 3.0. Overall, Ca2+ may reduce the negative effect of acid rain on the yield and nutritional quality of crops.
Assuntos
Chuva Ácida , Oryza , Oryza/metabolismo , Nitrogênio/metabolismo , Glutamato Sintase/metabolismo , PlântulaRESUMO
Microcystins (MCs) in irrigation water could inhibit crop growth and yield. Protein phosphatases (PPs) play an important role in regulating physiological mechanisms in plants to adapt abiotic stresses. To clarify the adaptation mechanism in plants to MCs stress, we compared PPs in rice and cucumber leaves by analyzing PPs total activity, protein phosphatase-2A (PP2A) activity and expression, as well as related growth and gas exchange parameters. After 7-day exposure of MCs (5 ~ 100 µg/L) and 7-day recovery without MCs, rice showed higher tolerance to MCs by analyzing dry weight and gas exchange parameters. Both crops may regulate PPs activity to adapt MCs stress by increasing the expression of genes encoding PPs. Among them, PP2A activity in two crops showed more sensitivity to MCs than total PPs activity. In addition, the higher expressions of PP2A catalytic and regulatory subunits and lower decrease PP2A activity were observed in rice leaves compared to cucumber. All results suggest that the expression levels of PP2A subunits could play a role in maintaining the activity of PP2A to regulating plant tolerance to MCs stress.
Assuntos
Cucumis sativus , Oryza , Microcistinas/metabolismo , Cucumis sativus/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Antioxidantes/metabolismoRESUMO
Interactive effects of cadmium (Cd(2+)) and acid rain on photosynthetic light reaction in soybean seedlings were investigated under hydroponic conditions. Single treatment with Cd(2+) or acid rain and the combined treatment decreased the content of chlorophyll, Hill reaction rate, the activity of Mg(2+)-ATPase, maximal photochemical efficiency and maximal quantum yield, increased initial fluorescence and damaged the chloroplast structure in soybean seedlings. In the combined treatment, the change in the photosynthetic parameters and the damage of chloroplast structure were stronger than those of any single pollution. Meanwhile, Cd(2+) and acid rain had the interactive effects on the test indices in soybean seedlings. The results indicated that the combined pollution of Cd(2+) and acid rain aggravated the toxic effect of the single pollution of Cd(2+) or acid rain on the photosynthetic parameters due to the serious damage to the chloroplast structure.
Assuntos
Chuva Ácida/toxicidade , Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Glycine max/efeitos dos fármacos , Clorofila/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Fluorescência , Luz , Fotossíntese/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/fisiologia , Glycine max/fisiologiaRESUMO
The construction of "Emerging Engineering Education" aims at cultivating high-quality graduates capable of engineering practice, innovation and international competitiveness. Bilingual courses have become one of the effective means to cultivate qualified students with skills of both professional knowledge and international communication. However, the teaching effect of most bilingual courses is not very ideal. Based on analyzing common problems in the current bilingual teaching, we take the bilingual course of environmental biotechnology as an example, and discusses possible improvement strategies from the aspects of the construction of teaching mode, the establishment of quality control system, the selection of textbooks and the optimization of assessment methods. Moreover, we summarize experience and shortcomings on improving the lecturers' ability, students' learning enthusiasm and school's support. It is expected to provide useful reference for improving the effect of bilingual teaching in biotechnology-relevant courses.
Assuntos
Currículo , Estudantes , Biotecnologia , HumanosRESUMO
Acid rain, as a typical abiotic stress, damages plant growth and production. Calcium (Ca) mediates plant growth and links the signal transduction in plants for adapting to abiotic stresses. To understand the effect of Ca2+ on plant adaptable response to acid rain, we investigated changes in activities and gene expression of antioxidative enzymes and fatty acid composition of membrane lipid in rice seedlings treated with exogenous Ca2+ (5 mM) or/and simulated acid rain (SAR, pH 3.5 / 2.5). Exogenous Ca2+ enhanced activities of superoxide dismutase, catalase and peroxidase isozymes in rice leaves under SAR stress by promoting activation of existing isoforms and up-regulation of Cu/Zn-SOD1, Cu/Zn-SOD2, Cu/Zn-SOD3, CAT1, CAT2 and POD1. Compared to SAR treatment alone, exogenous Ca2+ alleviated SAR-induced oxidative damage to cell membrane by enhancing antioxidative capacity, as shown by the decrease in concentrations of H2O2, O2- and malondialdehyde in rice leaves. Meanwhile, Ca2+ alleviated SAR-induced decrease in unsaturation of membrane lipid for maintaining membrane fluidity. Finally, exogenous Ca2+ alleviated SAR-induced inhibition on relative growth rate of rice. Therefore, Ca2+ could play a role in regulating activities of antioxidative enzymes as well as maintaining unsaturation of membrane lipid for enhancing tolerance in rice seedlings to acid rain stress.
Assuntos
Chuva Ácida/efeitos adversos , Adaptação Fisiológica , Antioxidantes/metabolismo , Cálcio/metabolismo , Isoenzimas/metabolismo , Oryza/enzimologia , Oryza/crescimento & desenvolvimento , Estresse Fisiológico/fisiologia , Produtos Agrícolas/enzimologia , Produtos Agrícolas/crescimento & desenvolvimentoRESUMO
Microcystins (MCs) in water for irrigation may damage crop growth and enter food chains to threaten human health. To evaluate the potential risk of irrigation water contaminated with MCs, we exposed rice at each of the seedling, booting, and filling stages to irrigation water spiked with MCs at 1, 10, 100, and 1000 µg/L for 7 days. Afterwards, all rice underwent a recovery (without MCs) till the harvest. Low MCs (1 or10 µg/L) during different rice growth stages did not affect its yield and nutritional quality and had no risk to human health. High-concentration MCs (100 or 1000 µg/L) during the seedling or booting stage caused a larger decrease in the nutritional quality and yield of rice grains than that during the filling stage. In addition, MCs at 100 µg/L during the booting stage or at 1000 µg/L during the filling stage potentially threatened human health. The effect of MCs on rice yield, quality, and health risk was associated with the MC concentration and rice growth stage. Irrigation water contaminated with moderate-concentration MCs should be of concern at the early growth stage of rice.
Assuntos
Microcistinas , Oryza , Humanos , PlântulaRESUMO
Microcystins released by cyanobacteria affect crop growth and productivity, and even food safety. Plant hormones play a vital role in regulating growth, development and stress response in plants. Therefore, we studied the response of hormones including abscisic acid (ABA), indole-3-acetic acid (IAA), Zeatin (ZT) and gibberellin (GA3) as well as hormone balances (IAA/ABA, ZT/ABA and GA/ABA) to cyanobacterial extract containing microcystins (1, 10, 100 and 1000 µg/L) during stress and recovery periods. Low concentration microcystins (1 µg/L) promoted growth of rice seedlings by increasing levels of IAA, ZT and GA3 and maintaining hormone balances. In addition, the up-regulation of OsYUCCA1 increased IAA level in rice roots by promoting IAA biosynthesis. High concentrations microcystins (10, 100 or1000 µg/L) inhibited growth of rice seedlings by reducing levels of IAA, ZT and GA3 and ratios of IAA/ABA, ZT/ABA and GA/ABA due to increased ABA level. The increase in ABA in rice seedlings induced by high concentrations MCs was resulted from up-regulation of OsNCED1, OsNCED3, OsNCED4 and OsZEP to enhance ABA biosynthesis, and was controlled by up-regulating expression levels of OsABAox1-3 for enhancing ABA catabolism as negative feedback. The highest concentration of MCs (1000 µg/L) caused irreversible damage to metabolisms of IAA and ABA, partly resulting in unrecoverable inhibition on rice growth. All results demonstrate that "low-concentration promotion and high-concentration inhibition" of microcystins was associated with changes in hormone levels and balances by affecting their metabolisms, and could be helpful for guiding agricultural irrigation with microcystin contaminated water.
Assuntos
Cianobactérias/metabolismo , Microcistinas/toxicidade , Oryza/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plântula/metabolismo , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Extratos Vegetais , Raízes de Plantas/metabolismo , Zeatina/metabolismoRESUMO
Acid rain is a global environmental issue due to inhibiting severely plant growth and productivity. To discover the tolerant mechanism in plants under acid rain stress, we studied the difference in response of two crops (rice and soybean) to simulated acid rain (pH 5.0 ~ 2.5) at growth and physiological, biochemical and molecular levels during exposure and recovery periods by hydroponics. By analyzing the change in relative growth rate, chlorophyll content and plasma permeability in rice and soybean, we found that rice could tolerate acid rain above pH 3.0 whereas soybean could tolerate acid rain above pH 4.5. By RT-PCR analyses, immunoprecipitation and enzyme kinetics study, we observed that pH 4.5 acid rain promoted the transcriptional expression of H+-ATPase genes and the phosphorylation of H+-ATPase and increased H+-ATPase activity in the two crops for resisting acid stress. The increased degree in soybean was larger than that in rice. Acid rain at pH 3.0 still promoted the transcription regulation to maintain H+-ATPase activity higher in rice for resisting stress but caused irreversible inhibition on express of H+-ATPase and decreased H+-ATPase activity in soybean. All results suggest that the different tolerance in rice and soybean to acid rain stress could be associated with difference in plasma membrane H+-ATPase at transcriptional regulation, post-translational modification and the substrate affinity.
Assuntos
Chuva Ácida , Glycine max , Oryza , ATPases Translocadoras de Prótons/metabolismo , Membrana Celular , Regulação da Expressão Gênica de Plantas , Estresse FisiológicoRESUMO
Acid rain is a global environmental problem that threatens agricultural production. Calcium (Ca), as a signal substance for physiological activities, has been known to regulate plant growth under abiotic stresses. To clarify whether calcium could be one of possible ways to alleviate the reduction caused by acid rain in agricultural production and investigate its regulating mechanism on adaptation of plants under acid rain stress, we studied the effect of exogenous Ca2+ (5 mM CaCl2) on growth of soybean at different growth stages (seedling, flowering-podding, and filling stages) as well as yield and grain quality of soybean under simulated acid rain (pH 4.5 or pH 3.0) stress. We found that the application of Ca2+ could regulate the activity of plasma membrane H+-ATPase, for mitigating the increase of ammonium and the decrease of nitrate and phosphorus in soybean roots, which mitigated the inhibition on growth and improved the yield and grain quality of soybean under simulated acid rain stress. In addition, the alleviating effect of exogenous Ca2+ on soybean was the most significant at seedling stage. The results indicate that the exogenous Ca2+ could enhance the adaptation of soybean and facilitate the recovery of soybean productivity and grain quality under simulated acid rain stress by maintaining the uptake of nitrate, ammonium, and phosphorus.
Assuntos
Chuva Ácida/análise , Cálcio/farmacologia , Glycine max/crescimento & desenvolvimento , Estresse Fisiológico/efeitos dos fármacos , Adaptação Fisiológica , Transporte Biológico , Cálcio/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/enzimologia , Modelos Teóricos , Nitratos/metabolismo , Fósforo/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Glycine max/efeitos dos fármacos , Glycine max/metabolismoRESUMO
Abscisic acid (ABA) regulates much important plant physiological and biochemical processes and induces tolerance to different stresses. Here, we studied the regulation of exogenous ABA on adaptation of rice seedlings to simulated acid rain (SAR) stress by measuring biomass dry weight, stomatal conductance, net photosynthesis rate, nutrient elements, and endogenous hormones. The application of 10 µM ABA alleviated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and decreases in contents of nutrient (K, Mg, N, and P) and hormone (auxin, gibberellins, and zeatin). Moreover, 10 µM ABA could stimulate the Ca content as signaling molecules under SAR stress. Contrarily, the application of 100 µM ABA aggravated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and contents of nutrient and hormone. The results got after a 5-day recovery (without SAR) show that exogenous 10 µM ABA can promote self-restoration process in rice whereas 100 µM ABA hindered the restoration by increasing deficiency of nutrients and disturbing the balance of hormones. These results confirmed that exogenous ABA at proper concentration could enhance the tolerance of rice to SAR stress.
Assuntos
Ácido Abscísico/farmacologia , Chuva Ácida , Adaptação Fisiológica , Oryza/crescimento & desenvolvimento , Aclimatação/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Giberelinas , Ácidos Indolacéticos , Fotossíntese/efeitos dos fármacos , Plântula/efeitos dos fármacosRESUMO
Effects of cerium (Ce3+) on photosynthetic characteristics were investigated by hydroponics under laboratory conditions when soybean seedlings were exposed to two levels of supplementary UV-B radiation. UV-B radiation badly inhibited the photosynthesis in soybean seedling, leading to a reduction in net photosynthetic rate (Pn), Hill reaction activity, light saturated photosynthetic rate (Ps) and apparent quanta yield (AQY), as well as the CO2 and light saturated photosynthetic rate (Pm) and carboxulation efficiency (CE). On the contrary, Ce obviously promoted the photosynthesis of plants by increasing Hill reaction activity, accelerating electron transport and photophosphorylation, and enhancing carboxylation efficiency. For Ce+UV-B treatments, the values of photosynthetic parameters were still lower than those of the control, but obviously higher than those of UV-B treatment. The results indicated that Ce alleviated the inhibition of UV-B radiation on the photosynthesis in soybean seedling to a certain extent. In correlating of Pn with Hill activity, AQY and CE, we found that the changes of photosynthetic rate were mainly influenced by the regulating effect of Ce on Hill activity and AQY at low level (0.15 W/m(2)) of UV-B radiation, but were dominated by the regulating effect of Ce on CE at high level (0.45 W/m(2)). Thus, Ce could regulate many aspects in photosynthesis of soybean seedling under UV-B stress. The regulating mechanism was close related with the dosage of UV-B radiation.
Assuntos
Cério/farmacologia , Fertilizantes , Glycine max , Fotossíntese/efeitos dos fármacos , Plântula/efeitos dos fármacos , Raios Ultravioleta , Agricultura , Dióxido de Carbono/metabolismo , China , Transporte de Elétrons/efeitos dos fármacos , Fotofosforilação/efeitos dos fármacos , Fotossíntese/fisiologia , Fotossíntese/efeitos da radiação , Plântula/fisiologia , Plântula/efeitos da radiaçãoRESUMO
Effect of cerium (Ce3+) on the growth, photosynthesis and antioxidant enzyme system in rape seedlings (Brassica juncea L.) exposed to two levels of UV-B radiation (T1: 0.15 W/m2 and T2: 0.35 W/m2) was studied by hydroponics under laboratory conditions. After 5 d of UV-B treatment, the aboveground growth indices were obviously decreased by 13.2%-44.1% (T1) and 21.4%-49.3% (T2), compared to CK, and except active absorption area of roots, the belowground indices by 14.1%-35.6% (T1) and 20.3%-42.6% (T2). For Ce+UV-B treatments, the aboveground and belowground growth indices were decreased respectively by 4.1%-23.6%, 5.2% -23.3% (Ce+T1) and 10.8%-28.4%, 7.0%-27.8% (Ce+T2), lower than those of UV-B treatments. The decrease of growth indices appeared to be the result of changes of physiological processes. Two levels of UV-B radiation induced the decrease in chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency by 11.2%-25.9% (T1) and 20.9%-56.9% (T2), whereas increase in membrane permeability and activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) by 6.9%, 22.8%, 21.5%, 9.5% (T1) and 36.6%, 122.3%, 103.5%, 208.9% (T2), respectively. The reduction of the photosynthetic parameters in Ce+UV-B treatments was lessened to 3.2%-13.8% (Ce+T1) and 4.9%-27.6% (Ce+T2), and the increase of membrane permeability and activities of antioxidant enzymes except POD in the same treatments were lessened to 2.4%, 8.4%, 6.6% (Ce+T1) and 30.1%, 116.7%, 75.4% (Ce+T2). These results indicate that the regulative effect of Ce on photosynthesis and antioxidant enzymatic function is the ecophysiological basis of alleviating the suppression of UV-B radiation on growth of seedlings. Furthermore, the protective effect of Ce on seedlings exposed to T1 level of UV-B radiation is superior to T2 level.