‘禅寺丸’大小孢子发生与雌雄配子体发育

为探究禅寺丸大小孢子发生及雌雄配子体发育过程,并观察是否存在花粉及胚囊败育现象,采用常规石蜡切片法对其大、小孢子发生和雌、雄配子体发育的过程进行观察。结果表明:禅寺丸花药四室,花药壁由表皮、药室内壁、中层和腺质绒毡层组成;小孢子母细胞减数分裂为同时型,四分体的排列方式为四面体型;成熟花粉粒为2-细胞型,有3个萌发孔;不同药室间及同一药室内的小孢子母细胞减数分裂不同步,且有巨大花粉(未减数花粉)的产生。子房8室,中轴胎座,胚珠倒生,双珠被,薄珠心和单孢原细胞;大孢子四分体直线排列,功能大孢子位于合点端,蓼型胚囊。禅寺丸花粉和胚囊发育过程多数正常,不仅可作为授粉树种,也可作为优良的杂交母本。

Study on sporogenesis and gametogenesis of Zenjimaru

To study the process of sporogenesis and gametogenesis of Zenjimaru and explore whether the pollen and embryo sac abortion exist in Zenjimaru,the process of megasporogenesis,microsporogenesis and development of female and male gametophytes were observed by paraffin section method.The results showed that:Anthers were tetradymous and the anther wall consisted of epidermis,endotheca,middle layer and glandular tapetum;Meiosis of microspore mother cell was followed by simultaneous cytokinesis and resulted in tetrahedral tetrads;Mature pollen grains were 2-cell type with three germ pores;meiosis of microspore mother cells among different anther locules or in the same anther locule was asynchronous with the formation of giant pollen (unreduced pollen).The ovary had eight locules with axile placenta and anatropous ovules;The ovule was bitegmic and tenuinucellate with single spore cell;Megaspore mother cell formed a linear tetrade through meiosis,and only the chalazal magaspore was the functional one;The development of embryo sac was of polygonum type.In conclusion,Zenjimaru not only can be used as pollination tree,but also can be used as excellent female parent in crossing because of the normal development of the most pollens and embryo sacs.