根瘤菌诱发合欢根毛的增生和根表层传递细胞的形成

传递细胞作为一种溶质短途运输的特殊结构最初是由Gunning等(1968)提出来的。现已在苔藓、蕨类、被子植物的生殖器官、茎、节、叶和根的维管系统中都发现了传递细胞的存在(Gunninget al.,1968;1969;Gunning,1977;Folsomet al.,1986;Pateet al.,1969;朱徵等,1999);但是在植物根表面上少有传递细胞的报道。自韩素芬等(1998)首次报道了根瘤菌可诱发刺槐根表面产生传递细胞,笔者在对合欢的研究中又发现了类似的情况,同时还发现根瘤菌不仅能诱导合欢根表面传递细胞的形成,而且在水培的情况下还能诱导合欢侧根根毛的产生。1材料与方法1·1合欢苗…

Proliferation of Root Hairs and Formation of Transfer Cells of Root Out-Layers in Albizia julibrissin Induced by Rhizobia

The aseptic seedlings of Albizia julibrissin were divided into two groups. One group was inoculated by rhizobia and the other was designed as control without inoculation. These two groups were all cultivated in sterilized cultured liquid for about two weeks. In the first group,the root hairs did not form on the main roots,but formed a lot on the base part of the lateral roots. In the second group, the root hairs did not form not only on the main roots but also on the lateral roots. The root segments which have distinctive deformation of root hairs from first group were cut off and fixed, in the meanwhile the corresponding root segments were cut off from the contrastive group and fixed. These two groups of roots segments were treated as semi-thin section and ultrathin sections, then were observed by optical microscope and transmission electron microscope. The result showed that the transfer cells with wall ingrowths on the tangential exowall of the root's epiderm and exodermis cells, are easy to be found in the root segments which has distinctive deformation of root hair. The wall ingrowth lies not only in root epidermal cells but also in the root exodermis cells, while there is no wall ingrowth in root epiderm and exodermis cells of A. julibrissin which is not inoculated by rhizobia. This suggested that the forming of root hairs and transfer cells in epiderm and exodermis of A. julibrissin is resulted from the inducement of rhizobia of A. julibrissin.