摘要:
本文研究了添加外源褪黑素对As3+胁迫下水稻种子萌发及生理指标的影响。结果表明：添加外源褪黑素能促进As3+胁迫下水稻种子的萌发，提高水稻的发芽势和发芽率，促进水稻幼苗的生长。当As3+浓度为100 μmol·L-1时，添加100 μmol·L-1褪黑素能使水稻种子发芽率和总根长比对照分别提高57.1%和50.0%。添加褪黑素能显著提高As3+胁迫下水稻幼苗中抗氧化酶系统过氧化氢酶(CAT)、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)的活性，并降低水稻幼芽中丙二醛(MDA)的含量。当As3+浓度为100 μmol·L-1时，添加50 μmol·L-1和100 μmol·L-1褪黑素导致水稻幼芽中POD活性比对照处理分别提高57.5%和114.8%，CAT活性提高29.4%和53.8%，SOD活性提高31.5%和56.0%，丙二醛含量比对照处理降低16.5%和31.9%。添加褪黑素也能显著提高As3+胁迫下水稻的根系活力，当As3+浓度为100 μmol·L-1时，50、100 μmol·L-1褪黑素处理后根系活力比对照分别提高42.4%和124.1%。这说明添加外源褪黑素可缓解As3+胁迫对水稻的脂质过氧化损害，有效降低As对水稻内膜的破坏，显著缓解As污染对水稻的毒害作用。
关键词:
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As3+
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褪黑素
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水稻
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氧化损伤
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萌发
Abstract:
Effects of adding exogenous melatonin on rice seed germination and some physiological indexes of rice under As3+ stress were investigated. The results showed that adding exogenous melatonin had a positive effect on the seed germination and growth of rice seedlings under As3+ stress. At As3+ concentration of 100 μmol·L-1, compared with the control treatment, adding 100 μmol·L-1 exogenous melatonin increased the germination rate by 57.1% and total length of roots by 50%. Adding of exogenous melatonin significantly increased autioxidant enzyme activities, such as CAT, POD, SOD, and decreased MDA content. At As3+ concentration of 100 μmol·L-1, compared with the control treatment, adding 50 and 100 μmol·L-1exogenous melatonin could significantly increase the activities of POD by 57.5% and 114.8%, SOD by 16.5% and 31.9%, CAT by 31.5% and 56.0% respectively, decrease MDA content by 16.5% and 31.9%. Adding of exogenous melatonin also significantly increased the root activity. At As3+ concentration of 100 μmol·L-1, compared with the control treatment, adding 50 and 100 μmol·L-1 exogenous melatonin could increase the root activity by 42.4% and 124.1%. The results suggested that application of exogenous melatonin could alleviate lipid peroxidation damage of rice under As3+ stress, effectively reduce the damage to the intracellular membranes of rice, and effectively alleviate the toxic effects of As3+ on rice.
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