【目的】杂种鹅掌楸(Liriodendron × sinoamericanum)有超越其亲本的优良特性,目前有关其有性生殖与种子败育机理的报道甚少,对于其花粉母细胞减数分裂进程及染色体行为的研究也鲜见报道。笔者详细观测杂种鹅掌楸花粉母细胞减数分裂的染色体行为规律,为鹅掌楸属非整倍体育种、杂交育种以及种质资源的保护提供重要的细胞学参考。【方法】以杂种鹅掌楸为材料,采用压片法观察花粉母细胞减数分裂进程及染色体行为变异。【结果】①杂种鹅掌楸花粉母细胞可以进行正常的减数分裂,其中80%的花粉母细胞可以完成减数分裂过程,产生形态正常的花粉;②花粉母细胞的减数分裂有明显的不同步性,在同一花托上下不同部位花药中的花粉母细胞分别处于不同的发育阶段,同一花粉母细胞中也存在减数分裂不同步情况;③约有20%的花粉母细胞在减数分裂过程中出现明显的染色体异常行为,如染色体滞后、染色体提前分离或微核;④在减数分裂过程中存在纺锤体行为的多样性,主要有平行纺锤体、垂直纺锤体和60° 或120° 纺锤体等多种纺锤体。【结论】尽管杂种鹅掌楸花粉母细胞减数分裂过程中存在染色体异常行为,但多数花粉母细胞能完成正常的减数分裂,产生形态正常的花粉,这暗示杂种鹅掌楸是一种可以用于杂交育种与非整倍体育种的优良材料。

【Objective】Liriodendron hybrids (L. ×sinoamericanum) have excellent characteristics beyond their parents. Currently, little is known about their sexual reproduction and seed abortion mechanisms, and there are few reports on the meiosis process and chromosome behavior of their pollen mother cells. This study provides a detailed observation of the chromosomal behavior of meiosis in pollen mother cells of L. × sinoamericanum hybrids. The results can provide important cytological basis for aneuploid breeding, hybrid breeding, and germplasm resource protection of Liriodendron.【Method】The collected anthers were squashed and stained with Carbol fuchsin before microscope study. Photographs of freshly prepared slides were taken with the automatic camera of Nikon Eclipse 50i microscope. 【Result】(1) Pollen mother cells of L. × sinoamericanum can undergo normal meiosis, 80% of which can complete the meiotic process, and produce normal pollen; (2) meiosis of pollen mother cells is asynchronous. The pollen mother cells in different parts of anthers above and below the same receptacles are in different stages, and meiotic asynchrony also exists within the same pollen mother cells. (3) 20% of pollen mother cells have obvious chromosomal abnormalities in the process of meiosis, including laggard chromosomes, prematurely separated chromosomes, and micronuclei; (4) there is a diversity of spindle behavior during meiosis, with a variety of spindles, such as parallel spindles, vertical spindles and 60° or 120° spindles. 【Conclusion】Despite the abnormal chromosome behavior during meiosis of L. hybrids pollen mother cells, most of the pollen mother cells are able to complete normal meiosis and produce pollen with normal morphology, which implies that L. hybrids is an excellent material that can be used for hybrid breeding and aneuploid breeding.