水杨酸对镉胁迫下莴苣幼苗生长和氧化胁迫的缓解效应

重金属Cd作为毒性较高的环境毒物,不仅危害植物的生长和发育,也对人类健康带来严重威胁.水杨酸(salicylic acid, SA)作为一类新型植物生长调节物质,在诱导植物抗性方面起重要调节作用.以笋王一号莴苣为试验材料,研究SA处理对Cd胁迫下莴苣幼苗生长的缓解作用和生理机制.结果表明,外源SA处理可以不同程度地缓解Cd对莴苣幼苗生长的毒害效应,促进根长和叶面积的增加;增加Cd胁迫下幼苗根和叶中SOD、CAT和APX的活性,降低G-POD 活性,减少MDA积累,减轻了Cd引起的氧化胁迫程度,以10 μmol/L 的SA处理缓解效果最好.

Relieving Effect of Exogenous Salicylic Acid on Seedling Growth and Oxidative Stress of Lettuce under Cadmium Stress

Cagmium (Cd) with a high toxicity in soil environment not only harms plants′ growth and development, but also threatens human health. Salicylic acid(a new plant growth regulator)can play an important regulative role in induction of plant Cd resistance. Sunwang 1, a lettuce variety, was tested by salicylic acids with different concentrations under different Cd stress to study the relieving effect on its growth and development and physiological mechanism. The results showed that the exogenous salicylic acid could relieve the Cd toxicity to seedling growth of lettuce in varying degrees, and lighten the oxidative stress caused by Cd stress through increasing its root length and leaf area, activity of SOD, CAT and APX in its seedling roots and leaves under Cd stress and reducing G-POD activity and MDA accumulation, and 10μmol/L salicylic acid had the best relieving effect on seedling growth of lettuce under Cd stress.