秋水仙碱诱导粗皮桉花粉染色体加倍研究

目前自然界仍未发现天然多倍体桉树的存在,建立人工诱导桉树未减数2n花粉技术体系对于推进桉树的多倍体种质创制及遗传改良的意义重大。本研究以粗皮桉为对象,探究其花蕾发育与小孢子母细胞减数分裂进程的特点,并对不同发育阶段花蕾施加秋水仙碱处理,诱导粗皮桉花粉染色体加倍。结果表明,待观察到小孢子母细胞减数分裂开始后48 h,即处于细线期至粗线期的花蕾占比最高时,在靠近花序位置的花枝上切口并导入0.5%浓度的秋水仙碱溶液处理6 h的效果最佳,人工诱导2n花粉的有效诱导率达到31.34%。诱导获得的粗皮桉2n花粉较普通单倍性花粉的形态差异显著。本研究揭示了粗皮桉花蕾发育与小孢子母细胞减数分裂的时序性关系,建立了基于花蕾着生位置和发育时数,即时判别粗皮桉小孢子母细胞减数分裂时期的方法,明确了采用秋水仙碱溶液处理诱导粗皮桉花粉染色体加倍的最佳时机和处理条件,为进一步开展桉树多倍体种质创新工作奠定了重要基础。

Pollen Chromosome Doubling Induced by Colchicine in Eucalyptus pellita

Natural polyploid has not been found in Eucalyptus yet. Therefore, the establishment of artificially inducing unreduced 2n pollen technology is of great significance for promoting the creation and genetic improvement of polyploid germplasm in Eucalyptus. In this study, Eucalyptus pellita was used as the research material to explore the characteristics of flower bud development and microsporogenesis. Colchicine treatment was applied to the buds at different developmental stages to induce pollen chromosome doubling. Results showed that the proportion of flower buds in the meiosis stages from leptotene to pachytene was the highest when they were at 48 hours after the initiation of meiosis. During this period, the flower branches closed to the inflorescence were cut an incision and infused with 0.5% colchicine solution for 6 hours. In this way, the efficiency of artificially induced 2n pollen was reached up to 31.34%. The morphology of 2n pollen was significantly different from the normal haploid pollen. This study revealed the temporal relationship between flower bud development and microsporogenesis in E. pellita, and established a method to instantly identify the specific meiosis stage of microsporogenesis based on the location and development time of flower buds. The best and optimal timing and treatment conditions for inducing unreduced 2n pollen with colchicine solution were also clarified. This study laid an important foundation for further innovation of polyploid germplasm in Eucalyptus species.