摘要 :Although monomeric Al species are often toxic in acidic soils, the effects of the aluminate ion (Al(OH) 4 − ) on roots grown in alkaline media are still unclear. Dilute, alkaline (pH 9.5) nutrient solutions were used to investiga...
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Although monomeric Al species are often toxic in acidic soils, the effects of the aluminate ion (Al(OH) 4 − ) on roots grown in alkaline media are still unclear. Dilute, alkaline (pH 9.5) nutrient solutions were used to investigate the effects of Al(OH) 4 − on root growth of mungbean (Vigna radiata L.). Root growth was reduced by 13% after 3 d growth in solutions with an Al(OH) 4 − activity of 16 µM and no detectable polycationic Al (Al13). This decrease in root growth was associated with the formation of lesions on the root tips (due to the rupturing of the epidermal and outer cortical cells) and a slight limitation to root hair growth (particularly on the lateral roots). When roots displaying these symptoms were transferred to fresh Al(OH) 4 − solutions for a further 12 h, no root tip lesions were observed and root hair growth on the lateral roots improved. The symptoms were similar to those induced by Al13 at concentrations as low as 0.50 µM Al which are below the detection limit of the ferron method. Thus, Al(OH) 4 − is considered to be non-toxic, with the observed reduction in root growth in solutions containing Al(OH) 4 − due to the gradual formation of toxic Al13 in the bulk nutrient solution resulting from the acidification of the alkaline nutrient solution by the plant roots.
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Acid atmospheric deposition results in increased levels of mobile aluminium (Al) in forest soils. Laboratory studies suggest that increased binding of Al to soil organic matter (SOM) in the forest floor results in decreased mobili...
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Acid atmospheric deposition results in increased levels of mobile aluminium (Al) in forest soils. Laboratory studies suggest that increased binding of Al to soil organic matter (SOM) in the forest floor results in decreased mobility of organic matter in soil water, viz. Lower concentrations of dissolved organic carbon (DOC). Other laboratory studies indicate decreased decomposition rates of SOM as a result o Al binding.
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The mobility of aluminium in sediments was evaluated through a one-step extraction with a strong chelating agent. Single and sequential extraction procedures for the extraction of Al were applied to four sediments from a polluted ...
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The mobility of aluminium in sediments was evaluated through a one-step extraction with a strong chelating agent. Single and sequential extraction procedures for the extraction of Al were applied to four sediments from a polluted region. A single-step extraction with 0.05 mol L~(-1) ethylenediaminetetraacetic acid (EDTA) was used, and compared with a standardized SEP as reference. The Al contents extracted into Na2EDTA were in good agreement with the sequential extraction that yeilds mobile and potentially mobile portion of Al. Extracted EDTA contents make up more than 70% of the first-three-step sum of the five-step extraction procedure. Thus, Na2EDTA extraction of Al could be applied to assess aluminium mobility changes in sediments and soils.
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In the greenhouse growth of two coffee-tree varieties, Catuai (sensitive) and Icatu (tolerant) to aluminum, was evaluated in surface-fertilized and limed soil following subsurface treatment with seven lime levels (0.0; 0.49; 1.7; ...
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In the greenhouse growth of two coffee-tree varieties, Catuai (sensitive) and Icatu (tolerant) to aluminum, was evaluated in surface-fertilized and limed soil following subsurface treatment with seven lime levels (0.0; 0.49; 1.7; 2.9; 4.1; 6.6 and 9.3 t/ha). Plants were grown for 6.5 months in soils in PVC columns, subdivided into two horizons. In the lower 12 - 34 cm depth horizon, soil Al saturation varied between 93 and 0%. For both varieties evaluated, shoot dry weight and leaf area remained unchanged following limestone application. This fact shows that surface layer correction permitted normal shoot growth. High Al saturation resulted in decrease of root dry weight percent, root length percent and root surface percent in the 12-34 cm horizon, which were compensated by higher percentages of these properties in the upper 0-12 cm horizon. The ratio between root surface - root dry matter (cm(2)/g) of Catuai variety was increased by limestone application to the lower soil horizons, indicating that roots turn longer and thinner, when Al soil saturation decreased. This also shows a great sensitivity to Al of the Catuai variety. In contrast, in the Icatu variety, all root characteristics remained stable at all levels of Al tested.
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Aluminum (Al) toxicity is a major constraint for plant root development and growth as well as crop yield in acidic soils, which constitute approximately 40% of the potentially arable lands worldwide. The mechanisms of Al tolerance...
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Aluminum (Al) toxicity is a major constraint for plant root development and growth as well as crop yield in acidic soils, which constitute approximately 40% of the potentially arable lands worldwide. The mechanisms of Al tolerance in plants are not well understood. As a whole systems approach, proteomic techniques have proven to be crucial as a complementary strategy to explore the mechanism in Al toxicity. Review here focuses on the potential of proteomics to unravel the common and plant species-specific changes at proteome level under Al stress, via comparative analysis of the Al-responsive proteins uncovered by recent proteomic studies using 2DE. Understanding the mechanisms of Al tolerance in plants is critical to generate Al resistance crops for developing sustainable agriculture practices, thereby contributing to food security worldwide.
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Excess aluminum (Al) in soils due to acid rain leaching is toxic to water resources and harmful to soil organisms and plants. This study investigated adverse impacts of Al levels upon earthworms (Eisenia fetida) from the latosol (...
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Excess aluminum (Al) in soils due to acid rain leaching is toxic to water resources and harmful to soil organisms and plants. This study investigated adverse impacts of Al levels upon earthworms (Eisenia fetida) from the latosol (acidic red soil). Laboratory experiments were performed to examine the survival and avoidance of earth worms from high Al concentrations and investigate the re sponse of earthworms upon Al toxicity at seven different Al concentrations that ranged from 0 to 300 mg kg~(-1) over a 28-day period. Our study showed that the rate of the earthworm survival was 100 % within the first 7 days and decreased as time elapsed, especially for the Al concentrations at 200 and 300 mg kg~(-1). A very good linear correlation existed between the earthworm avoidance and the soil Al concentration. There was no Al toxicity to earthworms with the Al concentration ≤50 mg kg~(-1), and the toxicity started with the Al concentra tion ≥100 mg kg~(-1). Low Al concentration (i.e., <50 mg kg~(-1)) enhanced the growth of the earthworms, while high Al con centration (>100 mg kg_(-1)) retarded the growth of the earth worms. The weight of earthworms and the uptake of Al by earthworms increased with the Al concentrations from 0 to 50 mg kg~(-1) and decreased with the Al concentrations from 50 to 300 mg kg~(-1). The protein content in the earthwormsdecreased with the Al concentrations from 0 to 100 mg kg~(-1) and increased from 100 to 300 mg kg~(-1). In contrast, the catalase (CAT) and superoxide dismutase (SOD) activities in the earthworms increased with the Al concentrations from 0 to 100 mg kg~(-1) and decreased from 100 to 300 mg kg~(-1). The highest CAT and SOD activities and lowest protein content were found at the Al concentration of 100 mg kg~(-1). Results suggest that a high level of Al content in latosol was harmful to earthworms.
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To assess the risk of aluminium (Al) toxicity during the restoration of the eutrophic lake Tiefwarensee by hypolimnetic addition of NaAI(OH)_4-solution (aluminate) the generally limnological monitoring was accompanied by fractiona...
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To assess the risk of aluminium (Al) toxicity during the restoration of the eutrophic lake Tiefwarensee by hypolimnetic addition of NaAI(OH)_4-solution (aluminate) the generally limnological monitoring was accompanied by fractionation of Al in water and using Al accumulation on fish gills as bioindicator. The concentration of reactive Al species in the alkaline water (pH 8) peaked at 2 mg L~(-1) in parts of the anoxic hypolimnion and was 0.088 ± 0.053 mg L~(-1) (n = 70) in the epilimnion during the five years of treatment During an Al treatment cycle in summer 2003, perches showed significant Al accumulation on gills (100 pg Al g~(-1) dw) whereas roaches, breams and silver carps remained unaffected. Thus, the Al toxicity towards several fish species seems to be low, although the concentration of reactive Al in the lake water increased by a factor of 2. However, high Al toxicity due to lake treatment with aluminate could not be excluded, as high Al-gill concentration was observed. An Al balance two years after the treatment indicates complete export of the added Al into the sediment.
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Acidic red soil from a forest in Jiangxi Province was selected to isolate aluminum (Al)-resistant microbes, from which eight fungi were isolated. Two strains (S4 and S7) were found to be extremely tolerant to Al concentrations of ...
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Acidic red soil from a forest in Jiangxi Province was selected to isolate aluminum (Al)-resistant microbes, from which eight fungi were isolated. Two strains (S4 and S7) were found to be extremely tolerant to Al concentrations of up to 550 mmol L-1 and could grow at low pH levels (3.20-3.11). Morphological and 26S rDNA sequence analyses indicated that strain S4 belonged to Eupenicillium, while strain S7 was an unclassified Trichocomaceae. Further investigation showed that both strains were endowed with the ability to resist Al; strain S4 accumulated such a substantial amount of Al that its growth was limited to a larger extent than strain S7. The lower amounts of Al adsorbed in the mycelium and the much larger amounts of Al retained in the medium, in addition to the color change of the culture solution, implied that these two strains may resist Al by preventing Al from entering the cell and by chelating Al by secreting unique metabolites outside of the cell.
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Considerable amounts of coal combustion products (CCPs) are generated when coal is burned for generation of electricity. To meet Clean Air standards, large amounts of S must not be emitted into the atmosphere, which means consider...
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Considerable amounts of coal combustion products (CCPs) are generated when coal is burned for generation of electricity. To meet Clean Air standards, large amounts of S must not be emitted into the atmosphere, which means considerable amounts of flue gas desulfurization Products (FGDs) are and will be produced. Beneficial uses of FGDs are continually being sought to reduce waste, decrease cost of disposal, And provide value-added products.
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Rhizosphere microbial communities play a major role in multiple soil functions. The aim of this study is to assess the relation of bacteria and organic acids in rhizosphere soil and community function induced by soybean genotypes,...
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Rhizosphere microbial communities play a major role in multiple soil functions. The aim of this study is to assess the relation of bacteria and organic acids in rhizosphere soil and community function induced by soybean genotypes, BX10 [aluminum (Al)-tolerant soybean] and BD2 (Al-sensitive soybean). Organic acid analysis in the rhizosphere soil indicates that BX10 increased the concentration of citric acid, whereas BD2 decreased it; malic acid was only found in the rhizosphere soil of BX10. Redundancy analysis results also showed that the two soybean genotypes induced distinct rhizosphere microbial communities, and citric acid and malic acid had a significantly positive correlation with rhizosphere bacteria of BX10. The community level physiological profiling showed that BX10 might have more influence than BD2 on the ability to metabolize organic C substrates. Sequence analysis indicates that two soybeans stimulate some rhizobacteria, such as species of Acinetobacter, Candidatus Amoebinatus, and uncultured proteobacterium. This study revealed that rhizobacteria of two soybeans may be related to their organic acid exudation.CAS Registry Numbers 77-92-9 6915-15-7
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