外源一氧化氮提高裸燕麦幼苗的耐碱性

采用营养液砂培方法,研究外源一氧化氮(NO)供体硝普钠(SNP)对NaHCO3胁迫下裸燕麦幼苗生长、活性氧代谢和渗透溶质积累的影响。结果表明,1~200μmol/L SNP能够缓解75mmol/L NaHCO3胁迫对裸燕麦幼苗生长的抑制作用,25μmol/L SNP的缓解作用最明显,可降低裸燕麦叶片O2·-、H2O2、丙二醛和有机酸含量,增强幼苗叶片超氧化物歧化酶、过氧化氢酶、过氧化物酶、抗坏血酸过氧化物酶和质膜H+-ATPase活性,提高叶片谷胱甘肽、可溶性糖、可溶性蛋白质、游离氨基酸、脯氨酸含量和K+/Na+,但对抗坏血酸含量影响不大。分析表明,外源NO可能通过激活抗氧化系统活性、促进渗透溶质积累和改善Na+、K+平衡缓解碱胁迫对幼苗的伤害和生长抑制,从而提高裸燕麦的耐碱性。

Exogenous nitric oxide elevated alkali tolerance of Avena nuda seedlings

The effects of sodium nitroprusside (SNP)as a nitric oxide (NO)donor on growth,leaf reactive oxy-gen metabolism and osmotic accumulation in naked oat (Avena nuda )seedlings under NaHCO3 stress were in-vestigated by a sand nutrient cultivation method.SNP exposure at concentration ranges of 1-200 μmol/L,es-pecially at 25 μmol/L,significantly alleviated NaHCO3-related growth inhibition of seedlings by decreasing the levels of O2 ·- ,H2 O2 ,malondialdehyde and organic acid,and increased the activities of superoxide dismutase, catalase,peroxidase,ascorbate peroxidase and plasma membrane H +-ATPase in leaves under 75 mmol/L NaHCO3 stress.Similarly,the concentrations of reduced glutathione,soluble sugar,soluble protein,free ami-no acid and proline as well as K+/Na+ ratio were also increased significantly in seedling leaves under the same stress,but ascorbic acid concentration was not affected significantly.The results indicate that NO may alleviate the damage and growth inhibition caused by alkali stress in naked oat seedlings via activation of antioxidant sys-tem activity,acceleration of osmotic accumulation and maintenance of Na+ and K+ balance,thus improving al-kali resistance of the naked oat plants.