云南松小孢子发生过程中绒毡层细胞的超微结构研究

云南松(Pinus yunnanensis Fr.)在小孢子囊发育早期,绒毡层原生质体发生收缩,并伴随着细胞壁厚度的增加。脂肪微滴和孢粉素物质沉积而形成周缘绒毡层膜。随着孢粉素物质的产生,绒毡层细胞质明显地液泡化。孢粉素物质在绒毡层细胞膨大的内质网槽库中形成,随后被排放到近邻的小液泡内或游离于细胞质中。孢粉素物质也可在特化的含片层的质体中形成,孢粉素依附在片层膜上,或释放到细胞质中。

ULTRASTRUCTURAL STUDY IN THE TAPETAL CELL DURING MICROSPOROGENESIS OF PINUS YUNNANENSIS FR.

During the early development of the mi-crosporagium in Pinus yunnanensis Fr.,thethickness of the callose walls increasesalongwith the contraction of the tapetal protopla-sts.The peritapetal membrane begins to beformed by the deposition of the sporopolleninmateral and lipid droplets.The vesiculationof tapetal cytoplasm obviously occured withappearance of the sporopollenin.The sporopol-lenin is formed in the expanded cisternae ofhe endoplasmic reticulum in the tapetum,and then discharged into the neighbouringvescles or cytoplasm.The sporopollenin ma-terial is formed in specialized plastids and thenadheres to the inner surface of lamella mem-branes.The lipid droplets are electron-opaquein the tapetal cytoplasm at the beginning ofsporopollenin production,but gradually dec-line.The lipid is possibly metabolized in thecisternae and ultimately form sporopollenin.There are many mitochondria nearby endopla-smic reticulum which forms sporopollenin.These mitochondria possibly supply energy forsynthesis of the sporopollenin.