【作者】 吴均章；

【导师】 韩素芳；

【作者基本信息】 南京林业大学 ， 森林保护学， 2004， 博士

【摘要】 为了证实根瘤菌对豆科植物根部传递细胞的诱导是否具有普遍意义，本文通过对豆科植物合欢（Albizia julibrissin）、紫云英（Astragalus simicus）、苜蓿（Medicago sativa）、三叶草（Trifolium pratense）、刺槐（Robinia pseudoacacia）、锦鸡儿（Caragana sinica）、豌豆（Pisum sativum）、大豆（Glycine max）无菌苗进行接菌和对照培养，取接菌苗根毛密集、形变明显的根段固定，同时取对照苗相应部位的根段固定。通过塑料半薄切片光镜观察和超薄切片透射电镜观察，结果表明：根瘤菌对这几种豆科植物根表层传递细胞均具有诱导作用。但传递细胞存在的部位这几种不同植物具有一定的差异，合欢根表层传递细胞主要分布在表皮和外皮层中；紫云英根表层传递细胞主要分布在表皮和根毛中；苜蓿根表层传递细胞主要分布在表皮或外皮层，有时也可以在表皮和外皮层中同时存在传递细胞甚至外皮层以内的一层皮层细胞中也可出现传递细胞，呈现表皮、外皮层和外皮层以内的一层皮层细胞同时诱发传递细胞的情况。三叶草根表层的传递细胞可分布在表皮，也可分布在外皮层中或在表皮和外皮层中同时存在。刺槐根表层传递细胞主要分布在表皮中，有时在外皮层和根毛中也出现。锦鸡儿根表层传递细胞主要分布在外皮层中，豌豆和大豆根表层传递细胞主要分布在表皮层中。 根瘤菌除了对这几种豆科植物的根表层传递细胞具有诱导作用外，本研究还发现它对合欢和刺槐的侧根根毛具有诱导作用，即接菌合欢幼苗的侧根基部具较多弯曲形变的根毛，而对照幼苗的侧根不具根毛。接菌刺槐幼苗侧根的根毛不仅又密、又长且形变明显，而对照幼苗侧根根毛短、直而稀。 通过对刺槐幼苗侧根根段的显微化学研究表明，接菌刺槐幼苗侧根具传递细胞的根段Fe³⁺的含量明显高于对照幼苗相应根段，说明传递细胞可能有增加对Fe³⁺吸收的作用。 用紫云英和刺槐的结瘤因子粗提物处理紫云英和刺槐无菌幼苗，都能引起这二种幼苗的根毛形变，但未能引起根段的膨大和空瘤的形成。通过对其根毛形变明显的侧根根段作塑料半薄切片，结果显示：结瘤因子能诱发紫云英根表层传递细胞的产生，而刺槐未发现有传递细胞的产生。说明对紫云英而言，根瘤菌对其根表层传递细胞的诱导，可能是通过结瘤因子起作用的。而对刺槐而言，也许是结瘤因子浓度不够，或有更复杂的原因。 观察到在大豆主根后生木质部导管周围分布有传递细胞，这能更好地说明导管具有主动运输和调节的功能。更多还原

【Abstract】 This study has investigated the legumes of Albizia julibrissin; Astragalus simicus; Medicago sativa; Trifolium pratense; Robinia pseudoacacia; Caragana sinica; Pisum sativum; Glycine max to verify if it is a common phenomenon that rhizobia can induce the forming of transfer cells on the legume’s root surface. After certain time of culture of the aseptic seedlings inoculated with Rhizobia, the root segments which had distinctive deformation of root hairs were selected to fix for prepare of specimens, meanwhile, the seedlings without Rhizobia are set and treated as the control. The semi-thin section and ultrathin section of prepared specimen were separately observed through optical microscope and transmission electron microscope. The result indicated that the rhizobia can induce the forming of transfer cells in all these plants, however, with different positions in different plants. The transfer cells of Albizia julibrissin distribute in the epidermis and exodermis. Those of Astragalus sinicus in epidermis and root hairs, those of Medicago sativa in epidermis or in the exodermis or in the epidermis exodermis and the cortex cells next the exodermis,Those of Triforlium pratense in the epidermis or in the exodermis or in the epidermis and exodermis at the same time, those of Robinia pseudoacacia in the epidermis exodermis and root hairs, those of Caragana sinicu in the exodermis.those of Pisum sativum and Glycine max in the epidermis.Except for the transfer cells, the rhizobia can also induce the lateral roots of Albizia julibrissin and Robinia pseudoacacia to produce more root hairs. There are more deformed root hairs on the lateral root’s base part of inoculated Albizia julibrissin’s seedlings than on the control. There are many longer and denser root hairs on the lateral roots of the Robinia pseudoacacia inoculated with rhizobia than on the controlThe microchemiscal study on the lateral root’s segments of Robinia pseudoacacia shows that there are more Fe3+ exist in the root segment of inoculated seedlings than in the contral, as maybe explained the hypothesis that the transfer cells will increase the absorption of the Fe3+After the aseptic seedlings of Astragalus sinicus and Robinia pseudoacacia were treated by nod factors, they all can be resulted in root hairs deformation. But we did not oberserved their root segments swell or the empty nodules form. The observation of semi-thin section of root segments with distinctive root hair diformation show that transfer cells formed on the root surface of Astragalus sinicus while not on the surface of the Robinia pseudoacacia. This suggests that the forming of the transfer cells of Astragalus sinicus was induced by rhizobia because of the nod factors.We find that there are many tranafer cells of the Glycine max around vessel elements in the metaxylem of the main root, which can explain the phenomenon of vessel’s active transport.更多还原