江南桤木根瘤及其内生菌超微结构的研究

用光学显微镜、透射电镜和扫描电镜对江南桤木(Alnus trabeculo sa Hand—Mazz.)根瘤形态解剖特征及其内生菌的超微结构进行了观察研究。 江南桤木根瘤属于典型的枝丛状类型瘤,多年生根瘤簇直径1—5cm。电镜图象表示,成熟根瘤的内皮层细胞中存在大量菌丝与泡囊,少数感染细胞产生大量多态形的拟类菌体细胞。菌丝分枝、具有高密度电子的单层细胞壁和单层壁的横隔膜,直径0.3—0.5μm,细胞质内有明显单位膜的中间体。成熟的泡囊园形或椭圆形,表面比较光滑,细胞壁不完整,直径为2—4μm。内生菌的这些不同发育形态与它们在共生固氮中的作用,本文也作了讨论。

A STUDY ON THEULTRASTRUCTURE OF THE ROOT NODULES AND ITS ENDOPHYTE OF ALNUS TRABECULOSA

The ultrastructure of the root nodule infecting cell of Alnus trabeculosa Hanb. Mazz and the shapes of the endophyte were observed by light microscope,scanning electron microscope and transmission electron microscope.The root nodules of A.trabeculosa Hand-Mazz may be called a typical rhizo-thamnion, normally 1-5 cm in diameter. Electron micrographs show that the hyphae, vesicles and bacteria-like cells were observed in the endodermis-cells of root nodules. The hyphae are filamentous, having a single layer of electron-dense cell wall, branched and septate, normally 0.3-0.5μm in diameter. An unit membrane mesosomes observed by electron microscope is very conspicuous. The mature vesicles are spherical or ellipse, having an incomplete cell walls, normaly 3-5μm in diameter. The roles played by the different forms of the endophytes in symbiotic nitrogen fixation were also discussed.