摘要:
用激光共聚焦扫描图象系统(LCSIS)和透射电镜追踪和表征满江红鱼腥藻在发育中的满江红孢子果内的去向及其超微结构的变化。进入满江红孢子果的鱼腥藻营养细胞连锁体与孢子果的长轴大体呈平行状态,并活跃排列,最后形成鱼腥藻营养细胞群体。该群体占据了整个孢子果果腔(由囊群盖围合而成)和大孢子囊(或小孢子囊)周围一切可用的间隙。当果腔开口闭合时,部分营养细胞开始了向厚垣孢子分化的进程。在孢子果发育中期,果腔内的营养细胞连锁体都变成了外部形态类似于厚垣孢子的细胞链。从营养细胞向厚垣孢子的分化经历了细胞质重组和膜系统重排等一系列超微结构的变化。诸如多角体(Carboxysome)、藻蓝素颗粒、核糖体和类囊体之类的细胞内含物在数量、大小、形状和分布等方面随着厚垣孢子本身及其宿主孢子果发育进程而改变。文章还讨论了共生藻与自生蓝藻在厚垣孢子分化模式与超微结构特征的异同及其意义。
关键词:
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满江红 /
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孢子果 /
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鱼腥藻 /
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共生 /
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超微结构
Abstract:
The fate and ultrastructural changes of Anabaena azollae entrapped into the developing sporocarps of Azolla pinnata were followed and characterized by laser confocal scanning image system (LCSIS) and transmission electron microscopy The entrapped vegetative Anabaena hormogonia tended to run parallelly to the long axis of the young sporocarps and underwent an active division,forming eventually an Anabaena colony,which occupied the entire indusial chamber and all the space available around the megasporangium or microsporangia Some of the vegetative cells initiated differentiation to akinetes while the opening of the chamber was closed At an intermediate stage of the sporocarp development,all the vegetative cells on the hormogonia gradually transformed into the akinete like chains Ultrastructurally the preakinetes underwent the cytoplasm reorganization and the membrane systems rearrangement The inclusions,such as carboxysomes,cyanophycin granules,ribosomes and thylakoids,varied in number,size,and their distribution in the cell along with the differentiation course of the akinete The similarities and differences in differentiation patterns and ultrastructural feature between the endophytic and free living cyanobacteria as well as their possible significance were discussed
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