外源褪黑素对盐胁迫下水稻种子萌发与幼苗生长的影响

Effect of exogenous melatonin on seed germination and seedling growth of rice under salt stress

为探究盐胁迫下外源添加褪黑素对水稻种子萌发与幼苗生长的影响,以‘糯稻89-1’为实验材料,对盐胁迫下水稻幼苗进行不同浓度(0、50、100、200、400和800μmol·L-1)褪黑素处理,测定种子发芽势、发芽率、根芽长、根芽鲜质量、抗氧化酶活性、抗氧化剂含量、渗透调节物质、活性氧(ROS)、丙二醛(MDA)及根系活力。结果表明:外源添加不同浓度的褪黑素能够促进盐胁迫下水稻种子的萌发与幼苗的生长,显著增强幼苗超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,显著增加抗坏血酸(AsA)和谷胱甘肽(GSH)含量,提高幼苗渗透调节物质(可溶性糖、可溶性蛋白和脯氨酸)的含量和根系活力,显著降低幼苗MDA和ROS的含量。外源褪黑素能够增强水稻幼苗抗氧化与渗透调节的能力,清除大量积累的ROS,缓解盐胁迫带来的氧化损伤,提高幼苗的耐盐性。

To evaluate the effects of exogenous melatonin on seed germination and seedlings growth of rice under salt stress,seed germination potential and rate,root and bud length,fresh mass of root and bud,antioxidant enzyme activity,antioxidant content,osmotic regulator content,reactive oxygen species(ROS),malondialdehyde(MDA)and root activity of‘Glutinous rice 89-1’seedlings under salt stress were determined by treatments with different concentrations(0,50,100,200,400 and 800μmol·L-1)of melatonin.The results showed that the exogenous addition of melatonin at different concentrations can promote seed germination and seedlings growth of rice under salt stress,the activity of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),ascorbate peroxidase(APX)in seedlings were significantly enhanced,ascorbic acid(AsA)and glutathione(GSH)content were dramatically increased,the content of osmotic regulator(soluble sugar,soluble protein and proline)and root activity were increased,while the content of MDA and ROS notably declined.In conclusion,exogenous melatonin can improve the antioxidant and osmotic regulation capacity of rice seedlings,remove a large amount of accumulated ROS,and alleviate the oxidative damage caused by salt stress and improve the salt resistance to seedlings.