甜菊花粉壁发育的亚显微结构

以电镜术研究了甜菊花粉壁的形成过程,四分体时期,四分孢子质膜为胼胝质壁之间形成初生外壁,原基粒棒下部和上部分别向侧面扩展形成基尼层和覆盖层,胼胝质壁消溶后,即以此为模板逐渐形成外壁雕纹,不连续的初生外壁所留下的空隙则确定了萌发孔的部位,随后外壁内层Ⅱ和内壁相继发育,在小孢子单核后期,外壁雕纹结构已基本完善,但内壁直至花粉二细胞时期才明显加厚.内壁和初生外壁物质来源于小孢子,次生外壁物质起源可能是小孢子和周原质团兼有之,内壁蛋白和外壁蛋白分别由小孢子和药胫提供。

Fine Structure Study on the Pollen Wall Development of Stevia rebaudiana Bertoni

The pollen wall formation of Stevia rebaudiana Bertoni was studied by electron microscopy. Primexine formed between the plasma membrane and the callose wall of the tetrad. The base and the top of probaculae extended to aide and formed foot layer and tectu'm. When the callose wall disappeared, exine sculpture was elaborated graduall yafter the pattern of the primexine templet. The intervals which formed by the discos ntinuous primexine were positions of the aperture. Then nexine I and intine . developed in succession. When microspore was in the later stage of one cell, the exine sculpture almost formed. But the intine did net thicken obviously untill the pollen developed to the stage of two cells. The materials of intine and primexine originated from the microspore, but it was possible that the sporopollenin of the exine originated from both the microspore and peripla-smodium. The protein in intine and exine criginated from microspore and tapetum respectively.