高领黄角苔孢子壁发育的超微结构研究

Ultrastructural observations of spore wall development in Phaeoceros carolinianus(Michx.)Prosk.

采用透射电镜技术对高领黄角苔(Phaeoceros carolinianus(Michx.)Prosk.)孢子发育过程进行超微结构研究。结果显示:(1)高领黄角苔成熟孢子壁由6层构成,由内到外依次是薄的内壁内层、厚而疏松的内壁外层、均质的外壁、薄的周壁1层、疏松层状的周壁2层、不连续的周壁3层;孢子表面的刺状和乳头状纹饰由外壁形成;孢壁的发育顺序为不完全向心型;从孢壁结构和发育顺序上看其与藓类植物相似。(2)在高领黄角苔孢子发育过程中出现初生外壁,它参与外壁的形成,这与苔类植物属同一类型,且其外壁的物质来源是外源的;孢子内质网和高尔基体参与其内壁的形成。(3)高领黄角苔孢子的周壁3层为不对称加厚的“三分层”状,与部分蕨类植物孢子周壁的结构特点具有一定的相似性,结合其周壁的复杂分层(3层),推测高领黄角苔周壁在苔藓植物中属于较进化的类型。

Spore development in Phaeoceros carolinianus(Michx.)Prosk.was studied using transmission electron microscopy.Observations showed that:(1)The mature spore wall of P.carolinianus moss was composed of six layers,including(from inner to outer)thin inner layer of intine,thick and loose external layer of intine,homogeneous exine layer,thin layer of perine 1,loose structured layer of perine 2,and discontinuous layer of perine 3.The spiny and papillary ornamentations on the spore surface were determined by the exine layer.Spore wall development was incompletely centripetal.Spore development was similar to that of mosses in structure and sequence of spore wall development.(2)Primexine occurred in spore development of P.carolinianus,participated in the formation of the exine.Primexine formation type was the same type as liverworts,and the formation material of the exine was exogenous.The endoplasmic reticulum and dictyosome participated in the formation of the intine.(3)The perine layer of P.carolinianus could be divided into three asymmetric thickening layers,with characteristics similar to that of some ferns.In consideration of complex stratification(three layers),we speculate that the perine of P.carolinianus belongs to a more evolutionary type in bryophytes.