[Objective] To determine the possibility to produce triploids by pollen chromosome doubling induced with high temperature exposure,and to produce new triploid germplasm to breed new varieties of Populus canescens with better resistance and serve for ecological environment protection.[Method] Based on the observation of male meiosis,pollen chromosome doubling induced by high temperature exposure to produce hybrid triploid was conducted using aceto-carmine staining and chromosome doubling technique in P.canescens.[Result] The results indicated that it took 5-6 days for pollen mother cells (PMCs) to complete meisois.Compared to other Populus species,no significant differences in process of meiosis was observed in P.canescens.However,significant asynchronism of male meiotic progress of PMCs in the same bud was observed.The top of PMCs developed faster than the basal of PMCs in the same male bud.However,the middle PMCs was the slowest ones.The optimum treatment combination to induce pollen chromosome doubling was to use 38 or 41℃ high temperature to treat male buds for 6 hours when the meiotic stages of PMCs were from diplotene to diakinesis.The highest frequency of 2n pollen is 58.03％.911 seedlings were obtained by crossing the treatment combination with higher frequency of 2n pollen with female gametes of P.alba.Among all the progenies,42 triploids were detected,and the highest triploid production rate was 10.71％.Correlation analysis between the frequency of 2n pollen and triploid production rate was carried out.Non-significant positive correlation was observed between the frequency of 2n pollen and triploid production rate (r=0.599,P =0.116),suggesting that increasing the frequency of 2n pollen could help increase the triploid production rate.[Conclusion] Though significant asynchronism of male meiotic progress of PMCs in the same bud was observed in P.canescens,56.33％ 2n pollen could be achieved when the PMCs were exposed to high temperature at diplotene to diakinesis.The highest triploid production rate was 10.71％.Our findings suggested that it was possible to produce triploid by induced pollen chromosome doubling by high temperature exposure and obtained triploid P.canescens for the first time.%[目的]验证高温处理诱导银灰杨花粉染色体加倍选育三倍体的可行性,获得银灰杨三倍体新种质,选育抗逆性强的银灰杨新品种,服务于西部生态环境建设.[方法]以银灰杨为研究对象,利用醋酸洋红染色法和花粉染色体加倍技术,在研究雄花芽减数分裂规律的基础上,开展高温诱导银灰杨花粉染色体加倍技术条件优化以及杂交创制三倍体的研究.[结果]银灰杨花粉母细胞完成减数分裂大约需要5～6天.其减数分裂过程与其他杨属植物相似,无明显差异.但银灰杨同一花芽不同部位花粉母细胞的减数分裂进程存在明显的不同步性,花芽顶部花粉母细胞发育最快,基部次之,中部发育最慢.筛选出高温诱导银灰杨花粉染色体加倍的最佳处理技术组合为当花粉母细胞发育至双线期至终变期时,利用38℃或41℃的高温,持续处理6h,可获得56.33％的2n花粉.利用2n花粉比率高的花粉与银白杨雌配子杂交,获得杂种苗木911株,检测出三倍体42株,三倍体得率最高可达10.71％.三倍体得率与2n花粉比率间存在弱正相关(r=0.599,P=0.116),说明提高2n花粉比率有助于提高三倍体得率.[结论]尽管银灰杨同一花芽不同部位花粉母细胞减数分裂同步性差,但在双线期至终变期进行高温处理,仍可获得56.33％的2n花粉,三倍体得率可达10.71％,证明了高温诱导银灰杨花粉染色体加倍选育三倍体的可行性,并首次获得银灰杨三倍体.
展开▼
