蕨类植物分株紫萁精子发生过程中生毛体和多层结构的超微结构

应用电镜技术对蕨类植物分株紫萁(Osmunda cinnamomea L. var．asiatica Fernald)精子发育过程中的生毛体和多层结构的超微结构进行了研究。牛毛体在幼精了细胞中出现，正在分化的生毛体略呈球状，球状体的中央由一团染色深的颗粒状物质构成，外围分化出若干柱状体。已分化的生毛体由柱状体分散或辐射状排列构成，呈球状，球体中心不含染色深的物质。多层结构位于精子细胞内的基体和巨大线粒体之间，刚形成时仅由片层构成，片层相互平行排列形成片层带。多层结构在分化中期由微管带、片层带和蚀斑三层构成。多层结构在分化末期又形成附属微管带、嗜锇冠和嗜锇层。微管带从多层结构长出，沿细胞核的表面伸展，并与核膜之间形成复合结构。基体由柱状体转变而成，它向两端生长，在远端产生鞭毛的轴丝，在近轴端形成楔状结构。本文首次详细阐明了原始薄囊蕨分株紫其生毛体和多层结构发育的超微结构特点，并与其他蕨类进行了比较，发现其片层带出现在微管带形成之前。

Ultrastructure of the Blepharoplast and the Multilayered Structure in Spermatogenesis in Osmunda cinnamomea var. asiatica

The ultrastructure of the blepharoplast and the multilayered structure (MLS) in the fern Osmunda cinnamomea var. asiatica Fernald have been studied by electron microscopy with respect to spermatogenesis. The blepharoplast appears in the young spermatid. The differentiating blepharoplast is approximately a spherical body, which is composed of densely stained granular material in the center and some cylinders outside of it. The differentiated blepharoplast is also a sphere, but without the densely stained material in the center, consisting of scattered or radially arranged cylinders. The MLS seen in the spermatid lies between the basal bodies and the giant mitochondrion. In the early developmental stage, the MLS only consists of lamellar layers, each of which runs parallel to one another and forms a strip. In the mid stage, the MLS is composed of the microtubular ribbon (MTr), the lamellar layers and a layer of plaque. In the late stage, the MLS forms accessory band, osmiophilic crest and a layer of osmiophilic material. The MTr grows out from the MLS and extends along the surface of the nucleus to unite with the nuclear envelope in a complex. The basal body coming from the cylinder produces the axoneme of the flagella in the distal end and the wedge-shaped structure in the proximal end, respectively. In the present study, the ultrastructural features of blepharoplast and the MLS of the protoleptosporangiopsida fern, O. cinnamomea var. asiatica, have been described and compared with those of other kinds of pteridophytes in detail. The lamellar layers appearing before the formation of the MTr was found and reported for the first time.