杜仲花粉壁发育的超微结构观察

Ultrastructural Observation on the Pollen Wall Development in Eucommia ulmoides Oliv.

利用透射电子显微镜和场发射扫描显微镜对杜仲花粉壁结构和发育进行了研究。结果显示,杜仲花粉在四分体末期形成原外壁,质膜随之出现波状样式,原基粒棒的形成在波状质膜的凹陷处积累,同时细胞中的核质类核仁向核膜外扩散,并进一步分布在质膜下;单细胞花粉早期其外壁结构(覆盖层、柱状层、基足层和外壁内层)已经分化完全,之后花粉内壁由萌发孔起始发育,然后全面增厚,至花粉成熟时萌发孔处的内壁变得很厚,并形成具有丰富径向微通道的结构,此时外壁内层崩溃解体。重点讨论了花粉外壁模式决定以及类核仁和花粉外壁形成之间的关系。

The development of the pollen wall in Eucommia ulmoides Oliv.were examined with transmission electron microscopy and field emission scanning microscope.Primexine was accumulated out of the microspore plasma membrance and then make some area of plasma membrance cave where the initial bacula is presented.At the same time the nucleoloids in the karyon penetrated karyotheca into the cytoplasm and spreaded under the plasma membrance.During the early microspore stage,the ektexine consisted of tectum,baculum,foot layer and endexine could be identified.Intine was initiated first from the germ pore and then thickened generally.When pollen matured,the intine had got thickening where many radial minuteness channeles were presented and the endexine was disintegrated.The pattern of the pollen wall formation and the relationship between the formation of pollen ektexine and the nucleoloids are dicussed in this paper.