水分胁迫下水杨酸对大麦幼苗抗氧化能力的影响

水杨酸是一种与植物逆境生理密切相关的生长调节物质.研究选取普通大麦为实验材料,通过不同浓度的外源水杨酸处理,考察其在水分胁迫下对大麦幼苗抗氧化能力的影响.结果表明,水杨酸的作用具有双重性:低浓度的水杨酸(＜0.30 mmol/L)可以改善水分胁迫下大麦幼苗的水分状况,并且降低丙二醛含量,维持较低水平的蛋白质羰基含量,减...

Effects of Salicylic Acid on the Antioxidant Activity of Barley Seedlings under Water Stress

Salicylic acid(SA) is a stress-related growth regulator in plants.In this study,the antioxidant activity of barley seedlings under water stress with 15% PEG solution was investigated.Before water stress,seedlings were pre-treated by exogenous salicylic acid with concentration from 0.05 to 0.50 mmol/L.Oxidative damage caused by water stress was estimated by the level of malondialdehyde(MDA) and protein carbonyl in seedling leaves.And the activity of antioxidant enzymes(SOD,CAT and APX) was also studied.Results showed that salicylic acid had dual effects: low concentration of salicylic acid(<0.30 mmol/L) improved the water content of stressed seedlings,and reduced the oxidant damage caused by water stress,since the MDA content decreased compared with the control,and the content of protein carbonyl stabilized at a low level.However,high concentration of salicylic acid(>0.30 mmol/L) aggravated the water deprivation of stressed seedlings,and greatly improved the level of MDA and protein carbonyl,thus causing more damage to seedlings under water stress.The reason for such effects was possible that high concentration of salicylic acid increased the accumulation of reactive oxygen species by regulating the activity of antioxidant enzymes.