【摘要】 【目的】确定低温诱导毛白杨花粉染色体加倍获得2n花粉的适宜温度范围，提高2n花粉诱导效率，优化完善低温诱导毛白杨花粉染色体加倍选育林木多倍体的技术体系。【方法】本研究以山西朔州的毛白杨雄花枝为试验材料，利用醋酸洋红染色法，在探究毛白杨雄花芽不同发育时期对低温敏感性差异的基础上，开展低温诱导毛白杨花粉染色体加倍技术条件的优化研究；利用获得的低温诱导型2n花粉与毛白杨、银腺杨雌株进行授粉杂交，通过流式细胞术和体细胞染色体计数法检测倍性。【结果】（1）相较于花粉母细胞时期，处于减数分裂阶段的毛白杨花粉母细胞对低温更加敏感，低温处理诱导毛白杨产生2n花粉的适宜温度范围为-13～-7℃；（2）处理温度、减数分裂时期和持续处理时长均对毛白杨2n花粉诱导率具有极显著影响，确定了利用-13℃的低温对发育至减数分裂Ⅱ中期的花粉母细胞进行5 h的持续处理是低温诱导毛白杨花粉染色体加倍的最佳处理组合，其2n花粉诱导率可达（31.11±2.93）%;（3）利用高频率的低温诱导型2n花粉分别与毛白杨、银腺杨单倍性雌配子进行授粉杂交，成功获得26株三倍体。【结论】本研究优化并完善了低温诱导毛白杨花粉染色体加倍选育三倍体的技术体系，提高了2n花粉诱导率，并通过低温诱导型2n花粉杂交获得了26株三倍体，建立了一种高效稳定的林木三倍体诱导方法。研究结果将为推动林木三倍体育种理论和技术的发展奠定重要的基础。更多还原

【Abstract】 [Objective] This paper aims to determine the appropriate temperature range for low-temperatureinduced chromosome doubling in pollen of Populus tomentosa to enhance the induction rate of 2n pollen,thereby improving polyploid breeding technology system of forest through inducing pollen chromosome doubling of P. tomentosa by low temperature. [Method] Based on an investigation of differential sensitivity at different developmental stages of male flower buds to low temperature in P. tomentosa, aceto-carmine staining method was used, the experimental conditions for inducing 2n pollen by low temperature were systematically optimized by taking male floral branches of P. tomentosa collected from Shuozhou, Shanxi Province of northern China. Furthermore, triploids were generated by pollinating the obtained lowtemperature-induced 2n pollen with female P. tomentosa and Populus alba×P. glandulosa, and were determined by flow cytometry and somatic chromosome counting. [Result](1) Compared with pollen mother cell stage, pollen mother cells(PMCs) of P. tomentosa at meiotic stage exhibited higher sensitivity for low temperature. The optimal temperature for inducing 2n pollen ranged from-13 to-7 ℃.(2) The dominant meiotic stage, temperature, and duration significantly affected the induction rate of low temperature-induced 2n pollen. The optimal treatment combination for inducing pollen chromosome doubling in Populus tomentosa by low temperature was determined to be 5 h of continuous treatment of pollen mother cells at-13 ℃ during metaphase II. The highest induction rate of 2n pollen was(31.11±2.93)%.(3) Twenty-six triploids were produced by crossing low temperature-induced 2n pollen with haploid female gametes of P. tomentosa and Populus alba×P. glandulosa. [Conclusion] In this study, to increase induction rate of 2n pollen, the technical system for inducing pollen chromosome doubling by low temperature in P. tomentosa has been optimized and 26 triploids were produced by crossing low temperatureinduced 2n pollen. Therefore, an efficient and stable method to produce triploids for woody plants is established. These results lay a solid foundation for the development of theoretical frameworks and technical applications in triploid breeding of forest trees.更多还原