外源褪黑素对砷胁迫下水稻幼苗生长的影响

Effects of exogenous melatonin on the growth of rice seedlings under As stress

采用溶液培养法研究外源褪黑素对砷(As)胁迫下水稻幼苗生长、生理指标和As积累的影响。结果表明,添加褪黑素可缓解水稻幼苗的As毒害,提高水稻株高、根长和生物量;同时,添加褪黑素也可以显著提高As胁迫下水稻幼苗中叶片和根系中的POD、SOD和CAT活性,降低MDA含量和O_2~■产生速率。与单独As处理相比,添加0.1~100μmol·L^(-1)褪黑素使水稻叶片和根系中POD活性分别提高38.6%~62.9%(除0.1μmol·L^(-1)褪黑素外)和37.4%~142.6%,SOD活性分别提高7.9%~27.3%和63.1%~96.0%,CAT活性分别提高16.7%~66.7%和41.6%~151.1%,MDA含量分别降低24.2%~40.7%和14.1%~51.9%,O_2~■产生速率分别降低12.4%~21.7%和28.3%~68.6%。说明添加适宜浓度的褪黑素可提高水稻抗氧化系统酶活性,降低膜脂过氧化,提高水稻抵抗As胁迫的能力。

Effects of exogenous melatonin on the growth,physiological indices,and arsenic（ As） accumulation of rice under As stress were investigated in solution culture. The results showed that melatonin addition alleviated the toxic effects of As on rice seedlings,and improved plant height,root length,and biomass of rice. Melatonin addition also significantly increased activities of antioxidant enzymes,such as POD,SOD,CAT,decreased MDA content and O2■ producing rate. Compared to single As stress treatment,adding 0. 1-100 μmol · L-1 melatonin significantly increased POD activities in leaves and roots by 38. 6%-62. 9%（ except for 0. 1μmol·L-1 melatonin） and 37. 4%-142. 6%,SOD activities by 7. 9%-27. 3% and 63. 1%-96.0%,CAT activities by 16.7%-66.7% and 41.6%-151.1%,but decreased MDA content by 24.2%-40. 7% and 14. 1%-51. 9%,and O2■ producing rate by 12. 4%-21. 7% and 28. 3%-68.6%,respectively. Our results confirmed that melatonin addition with suitable concentration could increase the activities of antioxidant enzyme,alleviate lipid peroxidation damage,and improve the resistance of rice to As stress.