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91.
为了探讨外源一氧化氮(NO)对镉(Cd)胁迫下高羊茅(Festuca arundinacea)生理响应的调节机制,采用水培方法,研究了不同浓度的NO供体硝普钠(SNP)对100 μ mol·L-1CdCl2胁迫下高羊茅幼苗生长、光合特性及矿质元素吸收的影响.结果表明:在Cd胁迫下,外施SNP能显著增加高羊茅叶片中NO含量,同时增加植株干重,提高根生长率和根系活力;增加叶片中叶绿素和类胡萝卜素的含量,提高净光合速率(Pn)、增强PSII反应中心最大光能转换效率(Fv/Fm) 等指标,显著增强了高羊茅地上部分与根对Ca,Mg,Zn和Fe的吸收,抑制了Cd向地上部分的转运.综合各项指标来看,100 μmol·L-1SNP效果最好,能够显著改善高羊茅叶片的光合活性,维持植株体内矿质元素平衡,从而缓解Cd胁迫对高羊茅光合作用的抑制,促进其生长并提高其耐受性. 相似文献
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94.
湘西铅锌矿区土壤和植物重金属污染现状 总被引:2,自引:0,他引:2
调查了湖南湘西铅锌矿区植物组成,研究了尾矿区土壤及周围植物根部土壤的Pb、Zn和Cd含量和基本理化性质,分析了在这些区域自然定居的11种优势植物体内的3种重金属元素的耐性、富集特性。结果表明,矿区土壤极端贫瘠,土壤中Pb、Cd和Zn含量分别达2 789.001、59.83和2 892.00 mg/kg,重金属污染极为严重。该矿区的主要优势物种为禾本科和菊科植物,其中野菊花、狗尾巴草和五节芒3种植物地上部生物量较大且对某些重金属向地上部转运能力较强,对重金属污染土壤有一定的修复潜力;地枇杷的地上部Cd含量最大,达152 mg/kg,转运系数为1.03,是潜在的Cd超富集植物。 相似文献
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96.
近年来,植物修复因其独特的优势备受推崇,尤其是当前植物内生细菌的应用为植物修复重金属污染土壤提供了有效的新方案.在植物修复过程中,耐重金属的内生细菌利用与植物的共生互惠关系,通过自身的抗性系统缓解重金属的毒性,促进植物对其迁移,并通过溶磷、固氮等途径改善植物营养以及分泌植物激素、铁载体、特异性酶、抗生素等作用,促进植物在逆境条件下的生长和对重金属的富集.本文综述了近年来国内外关于重金属抗性植物内生细菌促进植物生长、增强植物对重金属的抗性以及影响重金属在植物体内吸收、转运和积累的作用机制,系统分析了内生细菌促进植物修复重金属污染土壤的机理,并进一步讨论了植物内生细菌在重金属污染土壤植物修复工程中的应用前景与研究方向. 相似文献
97.
A.A. Belimov N. Hontzeas S.V. Demchinskaya S. Bullitta 《Soil biology & biochemistry》2005,37(2):241-250
Eleven cadmium-tolerant bacterial strains were isolated from the root zone of Indian mustard (Brassica juncea L. Czern.) seedlings grown in Cd-supplemented soils as well as sewage sludge and mining waste highly contaminated with Cd. The bacteria also showed increased tolerance to other metals including Zn, Cu, Ni and Co. The isolated strains included Variovorax paradoxus, Rhodococcus sp. and Flavobacterium sp., and were capable of stimulating root elongation of B. juncea seedlings either in the presence or absence of toxic Cd concentrations. Some of the strains produced indoles or siderophores, but none possessed C2H2-reduction activity. All the strains, except Flavobacterium sp. strain 5P-3, contained the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which hydrolyses ACC (the immediate precursor of plant hormone ethylene) to NH3 and α-ketobutyrate. V. paradoxus utilized ACC as a sole source of N or energy. A positive correlation between the in vitro ACC deaminase activity of the bacteria and their stimulating effect on root elongation suggested that utilization of ACC is an important bacterial trait determining root growth promotion. The isolated bacteria offer promise as inoculants to improve growth of the metal accumulating plant B. juncea in the presence of toxic Cd concentrations and for the development of plant-inoculant systems useful for phytoremediation of polluted soils. 相似文献
98.
Juxiu Liu Shanjiang Peng Benjamin Faivre-vuillin Zhihong Xu Deqiang Zhang Guoyi Zhou 《Journal of Soils and Sediments》2008,8(6):452-460
Background, aims, and scope Increasing soil acidification is a growing concern in southern China. The traditional green manures applied in the fields
mostly comprise legumes that tend to accelerate soil acidification. Moreover, acid deposition can act as a source of nitrogen.
Hence, we looked for new plant species that would enhance nutrient concentrations when used as green manure and would reduce
soil acidity or at least not worsen it.
Materials and methods We studied the use of Erigeron annuus (L.) Pers. for ameliorating acid soil in a pot experiment with simulated acid rain (SAR) treatments (pH 5.8 to 3.0) in an
open area in Guangzhou City. The pots were divided into two groups named A and B groups. On day 0, pots of A group were filled
with soil and planted with Erigeron annuus seedlings. Pots of B group were only filled with soil as the control. On day 40, seedlings of E. annuus were harvested and buried in the corresponding pots. On day 54, two seeds of Phaseolus vulgaris L. were sown in each pot in both groups. The growth and bean yield of P. vulgaris seedlings were then used to evaluate the effects of E. annuus on acid soil. Plant and/or soil samples were collected on days 0, 40, 54, and 150; corresponding parameters were measured.
Results Results showed that E. annuus could maintain a good growth even on very acid soil. On day 40, the pH decreased significantly (P < 0.0001) in the B group pots without E. annuus compared with the A group. On day 54, after E. annuus was buried as a manure, the soil pH of all A group treatments except the pH 4.0 treatment showed a significant increase compared
to day 40 (P < 0.01). At the same time, the application of E. annuus as a manure produced a significant increase of soil K and P (P < 0.001), Ca (P < 0.05), and Mg (P < 0.001) concentrations of all A group SAR treatments compared to their B group counterparts (except control pots for Ca).
The soil exchangeable K and available P concentration doubled, and Ca and Mg increased by around 25% in the presence of the
E. annuus manure application.
Discussion The higher soil pH in the A group than B group on the day 40 was due to a great absorption of NO3
− by the roots of E. annuus. The soil pH increase after E. annuus was applied to the soil of A group was attributed to the release of high amount of K, the mineralization of organic N, and
the oxidation of organic acid anions. Nutrient increase in the A group after E. annuus application was mostly the result of the nutrient release during the residue decomposition. The amelioration of the soil
was effective as demonstrated by the enhanced growth and bean yield of P. vulgaris seedlings on the manured soil compared to the seedlings grown on a control that was not manured.
Conclusions
E. annuus could maintain a good growth in the acid lateritic field soil. Cultivating this plant and applying it to the soil with a
rate of 1.6 ton ha−1 doubled the soil K and P concentrations and increased soil exchangeable Ca and Mg concentrations by around 25%. This species
would be a good green manure candidate for growing in the acid soils of southern China. Application of E. annuus also has beneficial effects on crop growth through reduced Al toxicity and cation leaching.
Recommendations and perspectives Since E. annuus would improve soil pH and nutrient concentrations with minimum care, it is recommended for treating acid soils with poor
yield whenever a low-cost solution is required. 相似文献
99.
P. Roberts 《Soil biology & biochemistry》2006,38(7):1812-1822
There is increasing environmental concern about the impact of endocrine disrupting chemicals (EDCs) on ecosystem sustainability and human health. Many EDCs are present within wastes which are routinely spread to land (e.g. biosolids). The aim of this study was to investigate the behaviour and fate of the EDC, 4-nonylphenol (NP), in a range of soils and to assess the potential risk it may pose to soil and freshwaters environments. We showed that NP was not persistent in soil, that NP mineralization was concentration-dependent and was stimulated by the addition of organic residues (e.g. biosolids, glucose, dead roots) but not by the presence of a rhizosphere. NP had no negative effect on soil respiration or plant growth unless present at extreme concentrations (?10,000 mg NP kg−1) and the uptake of NP by plants was very low. While NP was sorbed to the solid phase it could easily be leached from soil. Taking all of our results together, we conclude that the spreading of NP contaminated waste soil to soil probably poses a very low environmental risk to freshwater ecosystems and human health. 相似文献
100.
A pot culture experiment was conducted in green house to study the potential of chromium (Cr) phytoaccumulatory capabilities
of four promising agroforestry tree species viz., Albizia amara, Casuarina equisetifolia, Tectona grandis, and Leucaena luecocephala. Possibility of enhancement of Cr uptake by chemical (citric acid) and biological vesicular arbuscular mycorrhizal fungi
(VAM) amendments were also tried. Biologically stable speciation of Cr trivalent (Cr(III) and hexavalent Cr(VI) were used.
Cr(VI) was more toxic to the tree growth in terms of collar diameter (CD) increment in all the tree species than Cr(III).
In general, roots accumulated more Cr than shoots in all the tree species. There was more than 10 fold increase in root Cr
content in comparison with shoot Cr content in all the trees at all the concentration of Cr and all sources of Cr. Citric
acid significantly increased the Cr content in the tissues of roots in all the species under both speciation of Cr. The highest
increase in Cr content brought by 20 mM citric acid addition was in A. amara. Unlike citric acid, VAM treatment did not bring about a significant increase in the Cr content of all the tree species studied.
Results suggest that Albizia amara is a potential Cr accumulator with citric acid as soil amendment. The potential of this tree as a Cr phytoaccumulator may
be investigated in long-term studies. 相似文献