乌蕨孢子壁的形成和发育

利用光镜、扫描电镜和透射电镜对鳞始蕨科（Lindsaeaceae）乌蕨（Stenoloma chusanum Ching）孢壁的形成和发育进行了研究。结果表明乌蕨孢子两侧对称、单裂缝，表面具疣状纹饰。孢壁由内壁、外壁和周壁三部分构成。外壁在四分体阶段已基本形成，其表面光滑，质地均匀，由孢粉素形成。周壁是由绒毡层残余物在外壁表面沉积形成，可分为周壁内层、周壁中层和周壁外层三部分。在周壁中层与外层之间有一层均匀的空间。最后，本文探讨了孢壁的形成和发育规律，研究结果对揭示孢子纹饰和孢壁各层的形成过程、来源和稳定性有重要的意义，并为孢粉学和系统学研究提供基础资料。

The Formation and Development of Sporoderm of Stenoloma chusanum ( Lindsaeaceae )

The formation and development of sporoderm of the fern Stenoloma chusanum Ching (Lindsaeaceae) are studied by means of light microcope(LM),scanning electron microscope(SEM) and transmission electron microscope (TEM).The results as follow:the mature spores of Stenoloma chusanum Ching are bilateral and monolete.The surface of spore is smooth and shows a verrucate ornamentation.The sporoderm consists of endospore,exospore and perispore.The exospore which is formed by sporopollenin finishes its formation in the tetrad stage.Its surface is smooth and its texture is uniform.The perispore is formed by the tapetal residues which deposit on the outside of the exospore.The perispore can be distinguished into three layers,i.e.an outer perispore layer,a middle perispore layer and an inner perispore layer.It is obvious that a layer of space exists between the middle and the outer perispore layers.In the last,the formation and development of the spore wall are discussed.The results will contribute to a better understanding of the origin,development and formation process of the sporoderm of ferns.It also can provide basic information for the palynology and phylogeny.