秋水仙碱诱导杜仲花粉染色体加倍的研究

Pollen chromosome doubling of Eucommia ulmoides induced by colchicine.

在掌握小孢子母细胞减数分裂规律的基础上 ,就非离体状态下施加秋水仙碱溶液处理雄花芽诱导杜仲花粉染色体加倍进行了研究 .结果表明 :杜仲小孢子母细胞减数分裂粗线期为花粉染色体加倍的最佳处理时期 ,而秋水仙碱的有效处理浓度为 0 1%～ 0 2 % ,有效处理时间为 2 4～ 36h .在减数分裂粗线期采用 0 2 %的秋水仙碱溶液持续处理 2 4h ,或采用 0 1%的秋水仙碱溶液处理 36h ,获得的平均 2n花粉比率最高 ,分别为 2 7 6 %和 2 3 2 % ,其中最高处理可达 4 9 5 % .与白杨等树种离体水培状态下施加理化处理诱导 2n花粉相比 ,由于杜仲同一花芽内小孢子母细胞减数分裂具有不同步性 ,以及不同花芽在树上分布位置和相应小环境的差异 ,导致获得的 2n花粉比率相对较低 ,且不同重复的 2n花粉比率差别也很大 .此外 ,秋水仙碱处理后导致散粉延迟 ,相对于同一环境条件下的正常花芽散粉晚大约 2～ 3d ,但可以利用生长于不同小环境条件下杜仲花芽发育进程的时间差 ,如对定植于建筑物向阳处的雄株进行秋水仙碱溶液处理诱导 2n花粉 ,而给位于背阴处的雌株授粉等 ,实现人工诱导

Based on the meiosis law of microsporocyte of Eucommia ulmoides, the effective meiosis period, treating concentration of colchicine and duration of pollen chromosome doubling under the non-excised conditions are researched. The results indicate: The best period of doubling pollen chromosome of Eucommia ulmoides is the pachytene of meiosis; the most effective concentration of colchicine is 0.1%--0.2% and the optimal duration is 24--36 h. The highest average percentage of unreduced pollen by treating male buds for 24 hours with 0.2% colchicine or 36 hours with 0.1% colchicine can be obtained, which is 27.6% and 23.2%, and the highest proportion is 49.5%. Compared with Populus tomentosa, asynchrony of meiosis of pollen mother cell, difference of distribution position and microenvironment of buds lead to relatively smaller proportion of 2n pollen and great difference of each repeat. In addition, after the buds are treated by colchicine, the time of sending out pollen postpones for 2--3 days compared to other normal buds under the same environmental condition. However, we can make use of 2n pollen to help breeding research through the following methods: pollinating the female plants in the shade with 2n pollen, and treating the male exposed to the sun with colchicine, according to their different development periods owing to their own environmental conditions.