外源水杨酸对NaCl胁迫下大豆种子萌发和幼苗生长生理的影响

以大豆种子、幼苗为试验材料,采用砂培的方法,研究了0.2mmol·L-1外源水杨酸(SA)对100mmol·L-1 NaCl胁迫下大豆种子萌发、幼苗形态及生物量、膜脂过氧化和抗氧化酶活性的影响。结果显示:NaCl胁迫下,大豆种子萌发和幼苗生长受到显著抑制,且随着胁迫时间的延长(0~3d),大豆幼苗相对电解质渗漏率、硫代巴比妥酸活性产物(TBARS)含量显著升高,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性均明显降低。外源SA促进NaCl胁迫下大豆种子萌发和根茎生长,增加幼苗生物量积累,降低幼苗叶片相对电解质渗漏率和TBARS含量,增强其叶片SOD、CAT、APX活性。研究表明,NaCl胁迫能显著抑制大豆种子萌发和幼苗生长,而一定浓度的外源SA能有效提高NaCl胁迫下大豆种子活力及幼苗抗氧化酶活性,减轻膜脂过氧化程度,缓解NaCl胁迫所造成的伤害,提高大豆幼苗抗盐胁迫的能力。

Effects of Exogenous Salicylic Acid on Seed Germination and Seedling Growth Physiological Characteristics of Soybean under NaCl Stress

The effects of 0.2 mmol·L^-1 exogenous salicylic acid (SA) on seed germination,seedling morphology and biomass,membrane peroxidation,antioxidant enzymes in leaves of soybean (Glycine max L.) seedlings under 100 mmol·L^-1 NaCl stress were investigated by incubating with sand culture.The results showed that seed germination and seedling growth were significantly inhibited under NaCl stress;Relative electrolyte leakage and thiobarbituric acid reactive substance (TBARS) content were markedly increased;Activities of superoxide dismutase (SOD),catelase (CAT) and ascorbate peroxidase (APX) reduced constantly in leaves of soybean seedling under NaCl stress.While exogenous SA promoted seed germination and rootstock growth,increased biomass accumulation,reduced relative electrolyte leakage and TBARS content,improved activities of SOD,CAT and APX.The results suggested that NaCl stress inhibited significantly soybean seed germination and seedling growth,while certain concentration of exogenous SA could enhance seed vigor and antioxidant enzymes activities,reduce the degree of membrane lipid peroxidation,alleviate damages by NaCl stress,and promote salt resistance of soybean seedlings under NaCl stress.