用焦锑酸钾技术研究玉米叶片中的钙

应用改良的焦锑酸钾沉淀技术,研究了玉米叶绿体钙的亚细胞定位和缺钙对玉米叶片细胞结构的影响,结果表明,在玉米两种叶绿体的被膜、片层结构和基质中均有锑酸钙沉淀存在,其中的基粒类囊体和基质类囊体具有较高的钙水平.研究结果还表明,缺钙会引起玉米叶片维管束鞘细胞、筛管分子、伴胞和叶肉细胞内与膜结合的钙离子释放出来,呈不规则的锑酸钙沉淀散布在细胞内,同时使细胞的内膜结构(如内质网、液泡等)遭到破坏而解体,随着缺钙程度的加深,叶绿体的片层结构开始解体.这说明钙对叶绿体的功能和维持细胞膜结构的完整性起着重要的作用.

Studies of Subcellular Localization of Calcium in the Leaves of Maize with Potassium Pyruantimonatc Technique.

The subcellular localization of soluble calcium in chloroplasts and influence of Ca-deficie-ncy on cell structure of maize ( Zea mays L. ) have been determined by means of in situ precipitation with an improvsd method of potassium pyruantimonate technique and electron microscopy visualization. The results showed that calcium-containing antimonate precipitates ( CaPA)were associated with the envelope, lamella structure and stroma in two types of chloroplastes. Particularly the granum-thylakoid and stroma-thylakord showed a rather high density of calcium. It was observed that Ca-deficiency led to Ca that was in combination with intracellular membrane to be released from bundle sheath cells, sieve tubes, companion cells and mesophyll cells, and caused Ca-containing antimonate precipitates to be distributed irregulary in cells. The lamella structure in chloroplasts also disintegrated with continuation of Ca-deficiency.Frorn these reults, it is concluded that calcium played an important part in the function of chloroplasts and in preserving intact the endomembranc structure.