外源NO对NaCl胁迫下桑树种子萌发及幼苗生理生化特性的影响

Effects of Exogenous Nitric Oxide on Mulberry Seed Germination and Physiological Characteristics of Mulberry Seedling upon Salt Stress

为探明外源一氧化氮(NO)对桑树种子萌发及幼苗耐盐胁迫能力的影响,以桑品种桂桑优12号为试验材料,以NO供体硝普钠(SNP)处理60 mmol/L NaCl胁迫下的桑树种子和幼苗,统计种子萌发情况并测定幼苗生理生化指标。结果表明,0.1~0.2 mmol/L SNP处理能显著缓解NaCl胁迫对桑种子萌发的抑制,种子的发芽势、活力指数和幼苗株高、根长、鲜质量均比NaCl胁迫下提高;与NaCl胁迫处理的桑树幼苗相比,0.2 mmol/L SNP处理使幼苗叶片中的超氧化物歧化酶、过氧化氢酶和过氧化物酶活性分别提高了11.22%、27.72%和37.08%,叶绿素a、叶绿素b和2种叶绿素总含量分别提高了15.91%、54.33%和23.60%,叶片中的丙二醛含量和相对电导率分别降低了38.11%和35.74%,可溶性蛋白含量提高了1.29%。结果表明,适宜浓度外源NO处理可以缓解NaCl胁迫对桑树种子及幼苗的伤害。

To illustrate the effect of nitric oxide (NO)on germination of mulberry seeds and salt resistance of mulberry seedlings,by using mulberry variety Guisangyou 12 as the experimental material,NO donor sodium nitroprusside (SNP) was used to treat mulberry seeds and seedlings under 60 mmol/L NaCL stress.The seed germination was observed and physiological indices of seedlings were determined.The results showed that 0.1-0.2 mmol/L SNP could significantly relieved the damage caused by NaCl stress on germination of mulberry seeds.The germination potential and vigor index of mulberry seeds and the plant height,root length and fresh weight of seedlings were all higher than those under NaCl stress.Compared with mulberry seedlings treated with NaCl stress,the activities of superoxide dismutase, catalase and peroxidase in seedling leaves treated with 0.2 mmol/L SNP increased by 11.22%,27.72% and 37.08% respectively;the contents of chlorophyll a,chlorophyll b and the total content of chlorophyll a and b increased by 15.91%,54.33% and 23.60%,respectively; and the content of malondialdehyde and the relative con- ductivity decreased by 38.11% and 35.74% respectively,the content of soluble protein increased by 1.29%. This study showed that appropriate exogenous nitric oxide could alleviate the damage to seeds and seedlings of mulberry under NaCl stress.