Complete and reduced life cycles in Rhizobium.
Complete and reduced life cycles in Rhizobium.
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根瘤菌的完整和缩短的生命周期。
DOI：
10.1099/00221287-7-3-4-233
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发表时间：
1952
期刊：
影响因子：
--
通讯作者：
K. Bisset
中科院分区：
文献类型：
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作者：
K. Bisset
摘要：已发现来自多种宿主植物的根瘤菌菌株具有完整或缩短的生活史。在前者中，这是某些野生豆科植物和园林花卉菌株的特征，根瘤内的拟杆菌是分支和分隔的;自由生活阶段包括负责感染宿主植物的小的类细菌形式，以及类似芽孢杆菌的大的，偶尔为革兰氏阳性的形式，其产生专门的，coceoid swarmers和抗性内生孢子。大田作物根瘤菌普遍存在周期缩短现象。类菌体是外形不规则的单细胞;自由生活阶段被简化为单独的类菌体阶段，有时如此活跃地运动，以执行群集器的功能。这种情况被认为是退化和由于寄生习性。内生孢子的形成模式，这与芽孢杆菌的详细不同，进行了描述。生命周期中各个阶段的形态和轻微的革兰氏阳性倾向表明根瘤菌是杆菌科的一个专门属。可能与寄生植物B有关。多粘菌属，它也有生物化学的亲和力。
SUMMARY: Strains of Rhizobium from a wide variety of host plants were found to possess either a complete or a reduced life cycle. In the former, which was characteristic of strains from certain wild legumes and garden flowers, the bacteroids within the nodule were branched and septate; the free-living stages included small Bacterium-like forms which were responsible for infection of the host plant, and large, occasionally Gram-positive forms resembling Bacillus, which produced both specialized, coceoid swarmers and resistant endospores. The reduced cycle was commonly found in Rhizobium from cultivated field crops. The bacteroids were single cells of irregular outline; the free-living stages were reduced to the Bacteriumlike stage alone, sometimes so actively motile as to perform the function of swarmers. This condition is regarded as degenerate and due to a parasitic habit. The mode of formation of the endospores, which differs in detail from that of Bacillus, is described. The morphology of various stages in the life cycle and a slight tendency to Gram-positivity render it apparent that Rhizobium is a specialized genus of Bacillaceae. probably related to the plant parasitic B. polymyxa group, with which it also has biochemical affinities.