芡实绒毡层细胞发育的超微结构变化

芡实（ Ｅｕｒｙａｌｅｆｅｒｏｘ Ｓａｌｉｓｂ） 绒毡层细胞在小孢子母细胞时期， 质体出现明显的变形期，细胞中二核常相互贴近或呈嵌合状态， 细胞壁间层中胞间连丝发达。减数分裂期， 绒毡层细胞壁融解消失， 胞间连丝断离， 细胞间发育出现不同步现象。质体开始积累淀粉， 部分质体呈空泡状， 并出现质体膜内陷， 这与液泡具相似的功能。四分体时期， 绒毡层细胞内部结构开始解体。单核小孢子时期， 绒毡层细胞解体消失， 使小孢子后期发育的营养来源受到影响，作者认为这是生产上成熟花粉囊中花粉粒少而且发育不正常的主要原因之一。

Ultrastructural Changes in the Development of Tapetal Cells of Euryale ferox

The plastids of tapetal cellsof Euryale ferox in microspore mother cell stage appear changes in shape apparently. Twonuclei in a cell are always adhere to each other or in a state of mosaic. Well-developedplasmodesmata appear between the middle wall layers of two adjacent cells. During meioticcell division stage, wall of tapetal cells dissociates and disappears, plasmodesmata breakdown, asynchronous condition occurs in cell development. Deposition of starch in plastidsinitiates at this stage. Part of plastids vacuolated with invagination of plastidmembrane, which possess the same function as that of vacuole in the cell. In tetrad stage,the structures of tapetal cells begin to dissociate. In the uninucleate microspore stage,tapetal cells dissociate and disappear, which effect the source of nutritious material inthe later developmental stages of microspores. The authors believe that it is one of themain reasons that causes reduction of mature pollen grains in the pollen sac and unnormalpollen development in production.