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研究不同低温胁迫下 (3℃ ,-2℃和 -1 0℃下分别处理 0 .5、3、6、9、1 2 h)扁桃离体叶片中 MDA含量、CAT活性和类胡罗卜素含量以及反映组织受伤害程度的膜透性变化和叶绿素降解间的关系 ,以探明膜脂过氧化在扁桃叶片低温伤害中的作用。 3℃处理初期 ,CAT活性、类胡罗卜素含量显著增加 ,叶片无明显伤害症状 (水渍、黄化等 ) ;-2℃和 -1 0℃下随处理时间的延长 ,叶片膜透性增大、叶绿素含量下降、MDA积累增多 ;同时 CAT活性、类胡罗卜素含量显著下降。MDA含量的增加与组织受伤害程度 (膜透性增加及叶绿素降解 )及抗氧化系统 (CAT和类胡罗卜素 )水平下降之间具有极显著的相关性。以 7个扁桃品种的田间越冬伤害指数及冬季所测枝条的 LT50 代表植株的冬季抗寒性 ,以 -5℃下处理4h和 8h后所测叶片 MDA相对含量代表叶片的抗寒性 ,发现 2者呈显著的相关性 ,表明 MDA可以作为鉴定扁桃品种抗寒性的指标。
The MDA content, CAT activity and carotenoid content in detached leaves of Almond under different low temperature stress (0, 5, 3, 6, 9 and 12 h at 3 ℃, -2 ℃ and -1 0 ℃, respectively) And the relationship between membrane permeability change and chlorophyll degradation, which reflect the degree of tissue injury, in order to find out the role of membrane lipid peroxidation in the hypoxic injury of almond leaves. The activity of CAT and the content of carotenoid increased significantly at 3 ℃, but the leaves showed no obvious injury symptoms (waterlogging, yellowing, etc.). At -2 ℃ and -1 ℃, the leaf membrane permeability Increased, the content of chlorophyll decreased and the accumulation of MDA increased. At the same time, CAT activity and carotenoid content decreased significantly. There was a significant correlation between the increase of MDA content and the degree of injury (membrane permeability and chlorophyll degradation) and the decrease of antioxidant system (CAT and carotenoid). The winter injury index of seven Almond varieties and the winter cold resistance index of LT50 of the branches tested in winter were compared. The relative content of MDA in the leaves measured at -5 ℃ for 4h and 8h represented the leaf cold resistance, and found that 2 Showed significant correlation, indicating MDA can be used as an indicator of cold resistance of Almond varieties.