低温胁迫下董棕(Garyota urens L.)幼苗叶肉细胞内Ca~(2+)水平及细胞超微结构的变化
The Changes in Ca~(2+) level and ultrastructure in the Leaf Cells of Garyota urens L. under Low Temperature Stress
- 生命科学－已发表论文 
用焦锑酸钙沉淀的电镜细胞化学方法 ,研究了低温胁迫下董棕 (GaryotaurensL .)幼苗叶肉细胞内Ca2 + 水平的变化。研究结果表明 ,未经低温处理的董棕幼苗叶肉细胞 ,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 ;经 2℃ 48h低温处理后 ,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焦锑酸钙沉淀则显著减少 ,并且超微结构已初步显示出寒害的特征 ,叶绿体外膜部分破损 ,类囊体片层稀疏且排列不规则 ,光合速率明显下降等 ;经 2℃ 1 2 0h低温处理后 ,细胞间隙内的焦锑酸钙沉淀极少 ,有的也紧贴在细胞外壁上 ,而细胞基质和细胞膜上则分布有非常多的焦锑酸钙沉淀 ,在核基质和液泡中也可见到少量的焦锑酸钙沉淀 ,并且超微结构遭到了显著破坏 ,叶绿体结构完全被破坏 ,核膜与液泡膜严重破损 ,内部结构模糊 ,细胞只表现为呼吸作用 ,不进行光合作用。表明Ca2 + 的区域性分布的变化与植物抗寒性存在一定关系。The changes in Ca 2+ localization in the leaf cells of Garyota urens L. under chilling stress were investigated with calcium antimonate precipitate_electromicroscopic_cytochemical methods. When Garyota urens L. grew on the normal temperature, it was shown that the deposits of calcium antimonate being the indicator for Ca 2+ localization mainly concentrated within the vacuoles and intercellular spaces and there was also some Ca 2+ deposits in cell walls. But when Garyota urens L. was treated by the temperature of 2℃ for 48 h, the level of Ca 2+ increased in cytoplasm and plasma membrane, but decreased in vacuoles and intercellular spaces considerably. At the same time, the ultrastructure of chloroplasts suffered from chilling: the membrane of chloroplasts had been damaged, the layer of thylakoids was exiguous and unclear, the photosynthetic rate decreased evidently. And when Garyota urens L. was treated by the temperature of 2℃ for 120 h, the deposits of Ca 2+ mainly concentrated within the cytoplasm, nucleus and plasma membrane and there was also some Ca 2+ deposits in vacuoles, and the ultrastructure of some cells was simultaneously damaged severely: Chloroplasts structure, vacuole membrane and nuclear membrane had been damaged fully, the structure within the cell had become unclear, and the cell only have respiration. Thus it can be seen that there are some relations between the changes in Ca 2+ distribution within the cell and plant cold_hardiness.