外源褪黑素对不同价态砷胁迫下水稻种子萌发和生理指标的影响

Effects of exogenous melatonin on seed germination and physiological indices of rice under As^(3+) and As^(5+) stress

研究了外源褪黑素对不同价态砷胁迫下水稻种子萌发的影响,结果表明,外源褪黑素能缓解As^(3+)和As^(5+)胁迫下水稻种子萌发的不利影响。添加50和100μmol·L^(-1)褪黑素后,砷胁迫下水稻种子的发芽率、发芽势、根芽长及根芽鲜重均得到提高。同时,添加褪黑素也可以显著提高As^(3+)和As^(5+)胁迫下水稻幼芽中CAT、POD和SOD活性,降低MDA含量和O_2^(-·)产生速率。当As^(3+)浓度为50μmol·L^(-1)时,添加100μmol·L^(-1)褪黑素导致水稻幼芽中CAT、POD和SOD活性分别比对照处理提高54.2%、100.1%和43.1%,MDA含量和O_2^(-·)产生速率分别降低44.1%和55.6%;而在相同浓度的As^(5+)胁迫时,100μmol·L^(-1)褪黑素处理使CAT、POD和SOD活性分别提高62.1%、49.6%和47.3%,MDA含量和O_2^(-·)产生速率分别降低33.1%和34.8%。证实褪黑素可提高水稻总代谢水平和抗氧化系统酶活性,提高水稻对As^(3+)和As^(5+)毒害的耐受性。

We investigated the effects of exogenous melatonin on seed germination and some physiological indices of rice under As3＋ and As5＋stress. The results showed that 50 and 100μmol·L-1 melatonin addition had positive effects on seed germination and growth of rice seedlings under As stress. Melatonin addition significantly increased the activities of antioxidant enzyme,such as CAT,POD,SOD,but decreased MDA content and the rate of O2-· production.At As3＋ concentration of 50 μmol · L-1,compared with the control treatment,adding 100μmol·L-1 melatonin significantly increased the activities of CAT,POD and SOD of rice seedlings by 54.2%,100.1% and 43.1%,respectively,decreased MDA content and O2-· producing rate by 44.1% and 55.6%. At the same concentration of As5＋,adding 100 μmol·L-1 melatonin increased the activities of CAT,POD and SOD of rice seedlings by 62.1%,49.6% and 47.3%,decreased MDA content and the rate of O2-·production by 33.1% and 34.8%,respectively. The results suggested that the application of melatonin could alleviate lipid peroxidation damage in rice under As3＋ and As5＋stress,and effectively alleviate the toxic effects of As3＋ and As5＋on rice.