外源Ca^(2+)预处理对高温胁迫下辣椒叶片细胞膜透性和GSH、AsA含量及Ca^(2+)分布的影响

EFFECTS OFCa^(2+) PRETREATMENT ON PLASMALEMMA PERMEABILITY, GSH AND ASA CONTENTS, AND CALCIUM DISTRIBUTION IN PEPPER MESOPHYLL CELLS UNDER HEAT STRESS

以辣椒 (Capsicum annuum)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 (As A)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 As A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 。

In this study, young pepper ( Capsicum annuum L. cv. Xiang-Yan10) leaves were used to examine the effects of exogenous Ca 2+ pretreatment on electrolyte leakage, ascorbate(AsA) and glutathione(GSH) contents, and the change in Ca 2+ distribution in mesophyll cells under heat stress. The results show that exogenous Ca 2+ 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 control leaves. In the control pepper seedlings growing under normal temperature, deposits of calcium antimonate, an indicator for Ca 2+ localization, were observed within the vacuoles, intercellular spaces, and chloroplasts. This indicates that Ca 2+ pretreatment could induce changes in Ca 2+ distribution and significantly increase the Ca 2+ level in intercellular spaces, vacuoles and chloroplasts. When calcium-treated leaves were under heat stress at 40°, the amount of Ca 2+ located in intercellular space decreased, and most of them transferred to cytosol and chloroplast across the plasmalemma. The results suggest that exogenous Ca 2+ results in changes in Ca 2+ distribution between inter-and intracellular spaces and, as a result, the ultrastructure of mesophyll cells could be protected from damage caused by heat stress.