壳聚糖对水分胁迫下辣椒幼苗氧化损伤的保护作用

【目的】研究壳聚糖（CTS）对水分胁迫下辣椒幼苗抗氧化酶活性及渗透调节物质等生理指标的影响，探讨CTS对辣椒幼苗水分胁迫的保护作用。【方法】以熟性不同的3个辣椒品种为试材，研究不同浓度的外源CTS (10、30、50、80 mg•L-1)对水分胁迫下幼苗叶片氧化损伤的保护作用。【结果】水分胁迫下，熟性不同的3个辣椒品种的SOD、POD、Pro、MDA和EL均显著高于对照，而GSH和AsA的含量最低，且均与其它各处理差异显著；水分胁迫下喷施不同浓度的CTS可明显降低活性氧清除系统中SOD和POD的活性、提高可溶性蛋白质、GSH及AsA的含量，降低细胞质膜相对透性和MDA、Pro的含量。【结论】50、80 mg•L-1的外源CTS可以通过提高其抗氧化物质的含量，有效地阻止辣椒体内MDA和Pro的积累，缓解水分胁迫对辣椒幼苗造成的膜脂过氧化，增强辣椒幼苗的抗旱性。

Protective Effects of Exogenous Chitosan on Oxidative Damage in Pepper Seedling Leaves Under Water Stress

【Objective】The aim of the experiment was to study the protective effects of exogenous chitosan on protective enzymes, antioxidant substances, osmotic adjustment material and membrane lipid peroxidation of pepper seedlings under water stress.【Method】The protective effects of exogenous chitosan at different concentrations(10, 30, 50, 80 mg•L-1) on oxidative damage in leaves of pepper seedlings under water stress were investigated with peppers varieties ‘Longjiao No.3’, ‘Longjiao No.2’ and ‘Zhongyan No.8’ as materials.【Result】Under water stress, the activities of superoxide dismutase and peroxidase, proline content, malondialdehyde content and relative conductivity of pepper seedlings were significantly higher than that of control (P<0.05), and the contents of glutathione and ascorbic acid were significantly lower than other treatments. The activities of superoxide dismutase and peroxidase, the relative conductivity, malondialdehyde and proline content apparently decreased, but the soluble proten contents and the contents of glutathione and ascorbic acid increased in treatments of different concentrations of chitosan compared with control.【Conclusion】Chitosan at 50 and 80 mg•L-1 increased the content of antioxidant substances, effectively prevented the accumulation of malondialdehyde and proline, mitigated the lipid peroxidation caused by water stress, and enhanced the plant's drought resistance.