根瘤菌诱导紫云英根表面传递细胞的观察

对紫云英无菌苗进行接菌处理，以不接菌为对照。于灭菌无氮培养液中培养1周，在接菌处理的紫云英苗中，取根毛密集、形变明显的根段固定，同时在不接菌对照处理的紫云英苗中，截取相应部位根段固定。两组固定的根段分别进行塑料半薄切片光镜观察和超薄切片透射电镜观察。结果发现：经根瘤菌处理的根段，其根表皮细胞的外切向壁上，发育出大量壁内突结构，甚至在根毛细胞四周也发育出大量的壁内突结构，属典型的传递细胞。经透射电镜观察，这些壁内突结构主要为乳头状和盾状结构。而对照苗的根段内未发现壁内突结构，证明紫云英根表皮传递细胞的形成是由紫云英根瘤菌诱导所致。

Observation on the Transfer Cells in the Epiderm of Roots of Astragalus sinicus After Inoculation by Rhizobia

The aseptic seedlings of Astragalus sinicus were treated as two groups.One group was inoculated by Rhizobium astragalus and the other was designed as contrast without inoculation.These two groups were all cultivated in sterilized cultured liquid about one week.The root segments which have distinctive deformation of root hairs from first group were cut off and be fixed,meanwhile the corresponding root segments were cut off from the contrastive group and be fixed.These groups of roots segments were treated as semi-thin section and ultrathin sections,and then were observed by optical microscope and transmission electron microscope.The result shows:the transfer cells with wall ingrowths on the tangential exowall of the root epidermal cells is 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 hairs,while there is no wall ingrowth in root epidermal cells of Astranalus sinicus which is not inoculated by rhizobia.This proved that the forming of transfer cells in epiderm of Astragalus sinicus was due to the inducement of rhizobia of Astragalus sinicus.