平基槭花性别分化的细胞形态学观察

Morphological and Cytological Study on Floral Sex Differentiation of Acer truncatum Bge.

平基槭为杂性花,雄花与两性花同株,本文对其花性别分化过程进行了细胞形态学观察。结果发现,在花性别分化的早期,雄花和两性花的花芽中雌、雄蕊原基均具备,只是在花芽发育到一定时期,雄花的雌蕊原基发生选择性败育,败育发生在大孢子母细胞减数分裂为4个大孢子时期。两性花的雌蕊可以正常膨大结实,雄蕊花药虽然可以形成二核花粉,但不能正常开裂,属于不育雄蕊。初步分析认为,两性花雄蕊花药不能正常开裂与花粉囊壁纤维层木质化程度低有关。

The process of sex differentiation of Acer truncatum, an andromonoecious woody plant, was morphologically and cytologically observed. Results showed that at early phase of sex differentiation, both pistil and stamen primordia could be found in male and bisexual flower buds, but selective abortion occurred in the pistil pri- mordia of male flowers when macrosporocytes developed to megaspore tetrads. Pistils of bisexual flowers could de- velop and set fruits normally, and the stamens could produce mature two-celled pollen but the pollen could not dehisce. It is suggested that the failure of anthers of bisexual flowers to dehisce might be caused by the low lignification in fibrous layer.