外源Ca2+预处理对高温胁迫下辣椒叶片细胞膜透性和GSH、AsA含量及Ca2+分布的影响

摘要

In this study, young pepper (Capsi cum annuum L. cv. Xiang-Yan10)leaves were used to examine the effects of exo genous Ca2+ pretreatment on electrolyte leakage, ascorbate(AsA) and glutat hione(GSH) contents, and the change in Ca2+ distribution in mesophyll cell s under heat stress. The results show that exogenous Ca2+ pretreatment can alleviate the damage of cell membrane caused by heat stress. The amount of GSH and AsA in calcium-treated leaves under heat stress was higher than that in con trol leaves. In the control pepper seedlings growing under normal temperature, deposits of calcium antimonate, an indicator for Ca2+ localization, were ob served within the vacuoles, intercellular spaces, and chloroplasts. This indicat es that Ca2+ pretreatment could induce changes in Ca2+ distribution and significantly increase the Ca2+ level in intercellular spaces, vacuole s and chloroplasts. When calcium-treated leaves were under heat stress at 40°, the amount of Ca2+ located in intercellular space decreased, and most of t hem transferred to cytosol and chloroplast across the plasmalemma. The results s uggest that exogenous Ca2+ results in changes in Ca2+ distribution b etween inter-and intracellular spaces and, as a result, the ultrastructure of m esophyll cells could be protected from damage caused by heat stress.%以辣椒(Capsicumannuum)幼苗的叶片为材料，研究了外源Ca2+预处理对热胁迫下细胞质膜透性和谷胱甘肽(GSH)、抗坏血酸(AsA)含量变化及Ca2+分布的影响。结果表明：外源Ca2+预处理能减轻热胁迫引起的细胞膜破坏，能够减少叶片中GSH和AsA的破坏。热胁迫后，Ca2+具有从胞外转运到胞质内和叶绿体中的趋势；外施Ca2+预处理能够明显增加细胞间隙、液泡和叶绿体中的Ca2+颗粒密度,能够稳定热胁迫下叶肉细胞膜和叶绿体的超微结构。结果表明，外施Ca2+预处理可能通过改变细胞内外的Ca2+分布，减轻热胁迫对叶肉细胞的伤害。