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大花紫薇大小孢子的发生及雌雄配子体的发育

花匠小妙招
2024-12-01 15:04

摘要： 用石蜡切片法对不同发育时期的大花紫薇（Lagerstroemia speciosa）花朵进行解剖研究，探讨其大小孢子的发生及雌雄配子体的发育过程，结果发现：大花紫薇花药4室，花药壁由表皮、药室内壁、中层和腺质绒毡层构成，发育类型为双子叶型；小孢子四分体多为四面体型，偶见十字交叉型，胞质分裂为同时型；成熟花粉粒属于2-细胞型，具3孔沟，偶见败育现象；大花紫薇雌蕊具6~7心皮，子房6~7室，每室具多枚倒生胚珠，双珠被，厚珠心，大孢子4分体呈直线排列，近合点端大孢子发育为蓼型胚囊，成熟胚囊为7细胞8核。花粉及胚囊发育多数正常，大花紫薇可以作为优良的杂交母本；同时可以根据开花物候不同阶段花的形态特征，初步判断大花紫薇大、小孢子发生和雌、雄配子体的发育进程。

关键词: 大花紫薇, 孢子发生, 配子体发育, 胚胎学

Abstract: The flower anatomical structures of Lagerstroemia speciosa in different development stages were studied by using method of paraffin section. The formation of the sporophyte and the development process of male and female gametophytes were also surveyed. The results showed that anther has four chambers. The anther wall shows a dicotyledonous type, which be comprised of epidermis, endothecium, middle layer and glandular tapetum. Cytokinesis occurs simultaneously with meiosis in a microspore mother cell, and the formed tetrads are mostly tetrahedral while some are decussate type. The mature pollen grains are of a 3-cell type with three grooves, occasionally aborted. The gynoecium was composed of 6 7 carpels. The ovary has 6 7 locules and there are several anatropous ovules in each locule. The ovules are crassinucellate and bitegmic. The megaspore mother cell divides to a linear megaspore tetrad. The chalazal megaspore develops into a polygonum type embryo sac. The mature embryo sac contains seven cells and eight cell nucleus. The most pollen and embryo sac development are normal, and L.speciosa can be used as a fine female parent in the hybridization breeding. According to the flower morphological characteristics in different blooming phenophase, the process of megaspore and microspore formation and development of male and female gametophytes can be determined initially.

Key words: Lagerstroemia speciosa, sporogenesis, gametogenesis, embryology

中图分类号:

S665.2