梨果实发育中Ca2+在果肉细胞的定位及变化研究*

 用焦锑酸钾沉淀的细胞化学方法, 研究了􀀂 幸水 梨果实发育中果肉细胞的焦锑酸Ca²⁺ 定位变化及其与细胞超微结构的关系。结果表明: ( 1) 在未受精之前, 果肉细胞内未检测到Ca²⁺ 沉淀颗粒, 细胞核内的染色质少且染色淡, 细胞质的细胞器数量也少; ( 2) 受精后果肉细胞呈现大量的Ca²⁺沉淀颗粒, 主要分布在细胞核、细胞质、质体以及叶绿体外膜上, 含Ca²⁺沉淀颗粒的质体非常膨大, 导管和初期发育的石细胞内也密集分布Ca2+ 沉淀颗粒; ( 3) 受精1 周后果肉细胞的Ca²⁺移向细胞之间的连接处; ( 4) 生理落果的细胞和导管中Ca²⁺没有或极少, 但有的细胞内沿液泡膜有Ca²⁺分布; ( 5) 受精3~ 4 周后, 果肉细胞中很难检测到Ca²⁺沉淀颗粒, 此状态一直持续到果实采收, 但果实腐烂前Ca²⁺沉淀颗粒沿果肉细胞壁两侧出现。就Ca2+ 在果实发育中的作用及与细胞超微结构的关系等进行了讨论。

Studies on Localization and Change of Ca2 + in Fruit Flesh Cells during Fruit Development of Pear

Relationship between Ca 2 localization and change in the fruit flesh cells and cell ultrastructure during fruit development of pear ( Pyrus pyrifolia Nakai) cv. kosui were studied using the cytochemical method of antimonite precip itation technique. The results showed that before the fertilization no Ca 2 sediment particles could be detected in the flesh cells and there existed little chromatin and light staining was observed in the nucleous. After fertilization many Ca 2 sediment particles could be detected in the flesh cells, mainly distributed in nucleus, cytoplasm, plastids and exterior membrane of chloroplast. The plastids containing Ca 2 expanded greatly. In addition, Ca 2 sediment particles could be observed in vessels and primarily developed stone cells. It was found that Ca 2 moved to the linking space in between the fruit flesh cells one week after fertilization. There was little or no Ca 2 in the cells and vessels of physiologically dropped fruits, whereas Ca 2 was distributed along the vacuolar membrane of some cells. Three to four weeks after the fertilization it was difficult to detect the Ca 2 sediment particles in the flesh cells, which continued until the fruits were harvested. However, Ca 2 sediment particles appeared in both sides of flesh cell wall before the fruits rotted. Relationship between function of Ca 2 in fruit development and ultrastructure is discussed herein.