【摘要】 用焦锑酸钙沉淀的电镜细胞化学方法 ,研究了白骨壤叶片衰老过程中叶肉细胞Ca2 + 水平的变化 .结果表明 ,在白骨壤幼叶和成熟叶叶肉细胞中 ,焦锑酸钙沉淀颗粒大量出现在液泡和细胞间隙中 ,细胞壁中也可见少量沉淀 ,而细胞基质中则看不到焦锑酸钙沉淀 .在衰老叶中 ,细胞基质和细胞膜上焦锑酸钙沉淀增加 ,而液泡和细胞间隙中的锑酸钙沉淀则显著减少 ,并且叶绿体外膜部分破损 ,结构破坏 ,核膜与液泡膜内部结构模糊 ,叶绿素含量、净光合速率、气孔导率和蒸腾速率显著下降 .Ca2 + 的区域性分布的变化与植物叶片衰老密切相关更多还原

【Abstract】 Changes of Ca 2+ localization in leaf cell from Avicennia marina during leaf senescence were investigated with calcium antimoniate precipitate electromicroscopic cytochemical methods. In cells of young and matured leaves, the deposits of calcium antimoniate mainly concentrated within the vacuoles and intercellular spaces, and no Ca 2+ deposits existed in cytoplasm. But in cells of old leaves, the level of Ca 2+ increased in cytoplasm and plasma membrane, and decreased considerably in vacuoles and intercellular spaces at the same time. The inner structure and membrane of chloroplasts had been also damaged, nucleus and vacuole membrane were exiguous and unclear, and chlorophyll content decreased in old leaf cell. Conclusively, leaf net photosynthetic rate, stomatal conductance and transpiration rate significantly decreased during senescence. Ca 2+ localization in leaf cell had close relationship with leaf senescence.更多还原