紫萁孢子囊发育中多糖和脂滴的细胞化学观察

摘要

The ultrastructure of the sporoderm and the dynamic of polysaccharides and lipid droplets during the sporangium development in the fern Osmunda japonica Thunb.were studied using light microscopy,transmission electron microscopy and cytochemical techniques.The results showed that:(1) the sporangium of O.japonica consists of a layer of sporangium wall cells,2 layers of tapetal cells and archesporial tissue;(2) the sporoderm consists of exospore and perispore.The exospore,which can be divided into the outer exospore and inner exospore,is thick obviously.But,the perispore is thin and discontinuous.The ornamentations is short baculate and formed by the exospore.The inner exospore is composed of polysaccharides.Both outer exospore and perispore contain lipid materials.(3) Some lipid droplets are seen in the archesporial cells.As the sporangia develop,the amyloplasts in the spore wall cell degenerate.The size of the amyloplasts become small and the number of the amyloplasts decrease gradually.Then these amyloplasts are transported to the plasmodium of the tapetal layer.The amyloplasts are probably transformed into the precursors of sporopollenin and sporopollenin.The sporopollenin are converted into spherical bodies,which pass through the inner membrane of the plasmodium and enter to the sporangium cavity.Finally,these sporopollenin bodies are deposited on the surface of the spores.(4) during spore development,the polysaccharide materials are converted into lipid materials,which are stored in the spores in the form of lipid droplets.The metabolic characteristics of polysaccharides and lipid droplets are observed during the sporangium development,which provided fundamental data and information for studying sporogenesis.%采用光镜、透射电镜和细胞化学技术,对紫萁孢子囊发育过程中孢壁的超微结构和孢子囊内多糖和脂滴的分布及其动态变化进行研究,以探讨紫萁孢子囊发育过程中多糖和脂滴的代谢特征,为蕨类孢子发生的研究提供基础资料.结果表明:(1)紫萁孢子囊由1层囊壁细胞、2层绒毡层和产孢组织构成.(2)紫萁孢子壁由发达而分2层的外壁(外壁内层和外壁外层)和薄的不连续的周壁构成,由外壁形成棒状纹饰的轮廓;孢子外壁内层由多糖类物质构成,外壁外层和周壁均含有脂类物质.(3)在紫萁孢原细胞中观察到少量脂滴;随着紫萁孢壁的形成,囊壁细胞中淀粉粒的大小逐渐变小、数目先增加后减少,它们转运到内层绒毡层原生质团并转化为孢粉素前体物质,再穿过原生质团内膜表面进入囊腔,成为孢粉素团块或以小球形式填加到孢子表面形成孢壁.(4)紫萁孢子囊将多糖类营养物质转化为脂类,以脂滴的形式储藏在孢子中.