百合小孢子母细胞形成和发育过程中细胞间连接形态和结构的变化

超显微结构水平观察发现造孢时期细胞的壁较厚，由中间层，初生和次生壁组成，细胞间的连接为典型的细胞间连丝，减数分裂前间期的细胞壁主要由中间和初生壁组成，典型的胞间连丝消失，但局部位置上的中间层和初生壁组分缺失，构成约２００～８００ｎｍ，宽的“豁口”，进入分裂期后，次生壁组分急剧增加，当整个细胞壁加厚到２４０－５００ｎｍ时，细胞壁出现穿孔，穿孔过程似乎有下列两种方式：１）在细胞壁的一侧或两侧出现电子致

Morphological and Structural Changes of The Intercellular Connections during Formation and Development of Lily Microsporocytes

Examined under the transmission electron microscope,the cell walls of sporogenous cells were found being 230-270nm thick,made of middle lamella (ML),primary wall(PW) and secondary wall(SW),and occupied by typical plasmodesmata(PD).The walls of cells at pre meiosis interphase looked somewhat thinner and were mainly made of ML and PW elements.On the wall the typical PD was not visible,but some breaches existed,which commonly were 500-800nm wide and lack of both ML and PL elements.After cell division began,the SW element of the walls rapidly thickened.When they were 240-500nm wide,perforation process appeared.The process showed the following two forms:1) some electron opaque material first deposited at some sites on one or two sides of wall,and because of constantly accumulation,they stretched inward in the direction verticular to cell wall.The run through SW,PW and ML elements,and finaly whole thickness of the wall was drilled through.2) On two sides of cell wall,some bodies like secretory vacuoles containing dense electron opaque particles occurred, and then the wall being in touch with the bodies became thinner and thinner and finally was drilled through.When the cell wall reached up to 470-1700nm wide,cytomictic channels of 200-1500nm occurred and some of cyto plasmic or nuclear materials could be seen migrating to adjacent cells through them.The formation mechanism of the secondary PD and cyto mictic channel are discussed in the present paper.