水杨酸对水分胁迫下小麦幼苗生理生化特性的影响

为了明确水杨酸对水分胁迫下小麦幼苗的保护机制,筛选其有效增强小麦幼苗抗旱性的最适施用浓度。选用小麦品种洛旱6号为试验材料,采用室内水培法,观测并测定小麦幼苗在20%聚乙二醇（PEG）胁迫下经不同浓度水杨酸（SA）处理后的形态及生理指标。结果表明,水分胁迫下,外源SA能够提高小麦幼苗可溶性糖、可溶性蛋白质和氨基酸含量,增强超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性,降低超氧阴离子自由基（O₂ ^—.）、双氧水（H₂O₂）含量,减少丙二醛（MDA）积累,促进小麦幼苗地上部生长。施用SA可通过提高小麦幼苗渗透调节能力和抗氧化酶活性来降低活性氧产生速率,减轻膜脂过氧化程度,维持细胞膜的稳定性,缓解水分胁迫对小麦幼苗生长的抑制作用,本试验条件下以0.6mmol/L SA的效果最好。

Effects of Salicylic Acid on Physiological and Biochemical Characteristics of Wheat Seedling under Water Stress

In order to understand the protective mechanism of salicylic acid (SA) on wheat seedlings under water stress and to screen the optimal concentration for enhancing drought resistance of wheat seedlings, wheat cultivar Luohan 6 was used as material in this study. The effects of SA on the morphological and physiological indexes of wheat seedlings under 20% polyethylene glycol (PEG) stress were studied through hydroponic method. The results showed that the contents of soluble sugar, protein and amino acid, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) under the PEG stress increased after spraying of SA while the contents of superoxide free radical (O₂ ^—.), H₂O₂ and malondialdehyde decreased. It suggested the external application of SA could reduce the rate of reactive oxygen species production, reduce the degree of lipid peroxidation, maintain the stability of cell membrane and alleviate the inhibition of water stress on wheat seedling’s growth by improving osmotic adjustment ability and antioxidant enzyme activity. In this study, 0.6mmol/L SA was found to be best.