外源水杨酸对观赏羽扇豆高温胁迫的生理响应

选用5叶期观赏羽扇豆‘尖塔’品种为试材，喷施200 μmol/L水杨酸后进行30℃~45℃的高温胁迫，观测其叶片超氧化物歧化酶活性、过氧化物酶活性、丙二醛含量及可溶性蛋白和可溶性糖含量的变化，以阐明高温胁迫下观赏羽扇豆的防御机理。结果表明：高温胁迫下，外源水杨酸预处理可以提高观赏羽扇豆幼苗叶片中的超氧化物歧化酶活性和过氧化物酶活性，抑制丙二醛含量的增加，提高渗透物质可溶性蛋白和可溶性糖的浓度。且随着胁迫温度的升高，抗氧化酶活性和渗透调节物质含量逐渐升高，当温度超过40℃后，开始下降。叶片中过氧化物酶活性对SA处理比较敏感，可作为衡量其耐热性的指标。可见，外源水杨酸可以通过提高植株抗氧化能力和渗透调节物质、保护膜结构和功能来降低高温胁迫对观赏羽扇豆幼苗的伤害。

Physiological Effect of Exogenous Salicylic Acid on Ornamental Lupins under High-temperature Stress

Five-leaf stage seedlings of the ornamental lupin cultivar ＇ Minaretie ＇ were studied under high-temperature stress of 30℃-45℃ after spraying 2μmol/L salicylic acid.Leaf superoxide dismutase activity,peroxidase activity,malondialdehyde content,soluble protein and sugar content were measured in order to clarify the responsive mechanism.The results showed that salicylic acid pretreatment effectively increased superoxide dismutase and peroxidase activity,osmoregulation substance content of soluble protein and sugar,but restrained the increase of malondialdehyde content in leaf.Antioxidant enzyme activity and osmoregulation substance content increased with temperature.When the temperature was out of 40℃,they decreased.Peroxidase activity in leaf was sensitived to the treatment of salicylic acid and it could be used to an indicator to measure high-temperature resistance.Thus,the exogenous salicylic acid could reduce high-temperature stress to hurt ornamental lupin seedlings by improving antioxidation ability and osmoregulation substance content,protecting structure and function of cell membrance.