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| Effect of Exogenous Nitric Oxide on Active Oxygen Metabolism and Cadmium Accumulation in Alfalfa Seedlings Under Cadmium Stress |
| Received:June 24, 2015 |
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| KeyWord:nitric oxide(NO);alfalfa(Medicogo sativa L.);membrane lipid peroxidation;antioxidant enzyme;osmotic-regulating substance;cadmium accumulation |
| Author Name | Affiliation | | CHEN Yin-ping | School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China | | QU Miao-miao | School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China | | SU Xiang-nan | School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China | | NGABIRE Maurice | School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China | | YANG Zhi-juan | School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China | | YANG Shu-wen | School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China | | BAI Yu-lin | School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China |
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| Abstract: |
| Nitric oxide(NO) is currently believed to play significant roles in plant responses to environmental changes. In this study, the effect of exogenous nitric oxide on the membrane lipid peroxidation, osmotic regulation substances, antioxidant enzyme activities and cadmium accumulation in leaves, stems, and roots of alfalfa seedlings and its mechanisms were studied under cadmium(0.5 mmol·L-1 CdCl2) stress using sodium nitropprusside(SNP) as NO donor. Supplying 300 μmol·L-1 SNP remarkably reduced relative electric conductivity(REC), malondialdehyde(MDA) and hydrogen peroxide(H2O2) content, and superoxide anion(O2-·) -generating rate. Application of 400 μmol·L-1 SNP significantly promoted the synthesis of proline(Pro), soluble protein(SP) and carotenoid(Car). The effect of SNP on activities of antioxidant enzymes in leaves, stems and roots of alfalfa seedlings was dependent on SNP concentrations. Treatment with 100 μmol·L-1 SNP significantly enhanced activities of peroxidase(POD) in leaves and superoxide dismutase(SOD) and glutathione reductase(GR) in leaves and stems. Applying 50 μmol·L-1 SNP significantly enhanced activities of ascorbic acid oxidase(APX) in leaves, stems and roots. The POD activity in stems and roots was significantly enhanced by 400 μmol·L-1 SNP. Cadmium accumulation in leaves and stems was remarkably reduced by 200 μmol·L-1 SNP, whereas root cadmium was obviously decreased by 100 μmol·L-1 SNP. The results show that appropriate concentrations of exogenous nitric oxide could increase the content of osmotic-regulating substances and regulating activities of antioxidant enzymes to protect the membrane system stability and to alleviate Cd stress in alfalfa seedlings effectively. |
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