白杨大孢子母细胞减数分裂进程及其即时判别

以毛新杨、银腺杨为材料，对白杨大、小孢子母细胞减数分裂进程及其相互关系进行研究.结果表明:不同白杨的大孢子母细胞减数分裂进程存在差异性，其中，毛新杨大孢子母细胞减数分裂相对启动较早，水培84 h已进入减数分裂细线期，但减数分裂时间历时较长；而银腺杨雌花芽水培140 h才进入减数分裂细线期，其减数分裂进程相对较快；毛新杨、银腺杨大孢子母细胞减数分裂进入粗线期均需6～7 d时间.毛新杨、银腺杨大、小孢子母细胞减数分裂进程存在时序性相关，当小孢子母细胞减数分裂至四分体，大孢子母细胞才进入减数分裂细线期；而当大孢子母细胞减数分裂到达粗线期时，小孢子多数已发育至单核靠边期.根据雌雄配子发生、发育的时序性对应关系，通过相同培养条件下小孢子发育进程的观察，可以对白杨大孢子母细胞减数分裂进程进行即时判别. 

Stages of MMC meiosis and its timely discrimination of white poplars.

The meiosis stages of megaspores and microspores of two white poplars (Populus tomentosa × P. bolleana and P. alba × P. glandulosa) and their relationships were studied. The results indicate that the meiosis stages of megaspores of these two white poplars are different. When cultured in water in the greenhouse for 84 h ,the meiosis stages of the megaspores of Populus tomentosa × P. bolleana developed into leptotene and the meiosis stages lasted very long. Those of P. alba ×P. glandulosa split into leptotene when cultured in water for 140 h and the meiosis stages were shorter. When the flower-branches cultured in water for 6-7 d, their meiosis stages of megaspores developed into pachytene. In the process of the experiment, the branches with buds of white poplar were collected and cultured under the same conditions, their meiosis stages of megaspores and microspores were closely related with development. When the meiosis of microspore mother cells developed into tetrads, that of megaspore mother cells just entered leptotene. When the meiosis of megaspore mother cell developed into pachytene, most of microspores developed into mononuclear that its nucleus had moved to one side of the cell. According to the relationship of female and male gametes, the meiosis stages of megaspore could be discriminated timely through observing the meiosis of microspores under the same conditions.