离体培养植物细胞的表面与细胞粘连

对离体培养的胡萝卜（Ｄａｕｃｕｓｃａｒｏｔａ）细胞和普通烟草（Ｎｉｃｏｔｉａｎａｔａｂａｃｕｍ）细胞的表面进行了扫描电镜观察．观察表明，细胞的自由表面上有很多疣突和纤丝．疣突的大小不同、形状各异，主要含果胶质；有些细胞表面出现小坑，坑中集中有许多微小颗粒．疣突相互可融合成更大的疣突或连成桥；纤丝常与疣突结合．纤丝－纤丝的交织，纤丝－疣突的交联，及疣突－疣突的融合，在细胞壁外表面构成交织的网络．同种细胞之间及异种细胞之间均可通过纤丝、疣突的交织融合而粘连．疣突分布不均一，且与细胞的分散性有关．与疏松烟草愈伤组织比较，致密烟草愈伤组织细胞的自由表面上疣突显著较多．在分化再生时，烟草愈伤组织首先致密变绿，然后才见到芽的分化及植株再生．对疣突出现、壁物质沉积与细胞粘连、细胞分化、形态建成几者之间的关系进行了讨论．

THE SURFACES AND ADHESION OF THE PLANT CELLS CULTURED IN VITRO

The cell surfaces of carrot (Daucus carote)and tobacco(Nicotiana tobacum)cultured in vitro were studied using scanning electron microscopy.Protuberances or warts,in various shapes and sizes and mainly containing pectin,and fibrils occurred on the flee surfaces(or outer surfaces of cell walls)of the plant callus cells.There were groups of mini-warts in the pits on the free surfaces of some cells.The warts could be fused and became big ones or combined and became bridge form,and were often associated with librils.The fibril interwoven,fibril-wart associstion,and wart-interfusion fored the Polymeric networks on the outer surface of the cell wall.It was thought that the deposition and assembly of the primary wall components into a growing wall were carried out mainly by intercalating onto the outer surface of the existing wall.Individual cells,being homogeneous or heterogeneous,could adhere yi3 the interwoven polymeric networks of fibrils and warts.The occurrence of warts on the cell surface,being different from cell to cell,might affect the dispersivity of the cells.Compared with friable white tobacco callus cells from subcultures,there were more warts remarkably on the free surfaces of compact tobaccoo callus cells from white compact calli cocultured with green carrot calli or from pale green compact calli cultured on the regeneration medium. During plant regeneration,the white friable tobacco calli first became compact and pole green,then adventitious buds appeared and plantlets or shoots would resenerate.Thus,it was concluded that the cell adhesion based on the assembly of wall components,charactcrized by the occurrence and interwoven of warts and fibrils on the outer surface of the cell wall,was essential for the cell differentiation and morphogenesis.The significance of the cell adhesion was discussed.