骆驼刺根瘤菌的超微结构研究

用透射电子显微镜研究骆驼刺根瘤中的根瘤菌。结果表明。在成熟的骆驼刺根瘤中，根瘤菌的大小、数量、形态、分布位置及精细结构随寄主细胞的发育程度不同而异。早期侵染细胞中，根瘤菌小，数量少，一般呈球形或椭球形，位于细胞壁附近及靠近核区的地方，没有聚磷酸盐颗粒和聚羟基丁酸。成熟侵染细胞中，根瘤菌个体较大，数量较多．多呈棒状，少数为球形或椭球形。有很多根瘤菌还呈现明显的“T”形、“Y”形或“V”形，菌体占满了整个细胞，这时的根瘤菌大多数含有聚羟基丁酸和聚磷酸盐颗粒。而在衰老的侵染细胞中，根瘤菌细胞质收缩，电子密度增高．形状变得很不规则，有的根瘤菌解体，呈现膜泡状结构，菌体中含有数量不等的聚羟基丁酸和聚磷酸盐颗粒。球状根瘤菌从侵染初期到侵染细胞裂解的整个阶段中都仔在。并且观察到的处于分裂状态的根瘤菌都是球状菌，因此可以推测骆驼刺根瘤中是以球状根瘤菌来进行增殖的。

Ultrastructural Study on the Rhizobia in Alhagi sparsifolia

The rhizobia in the root nodules of Alhagi sparsifolia were studied by transmission electron microscopy.The results indicated that the size,shape,distribution and fine structures of the rhizobia were related with the stage host cell development.The rhizobia in young infected cells were small,few in number,spherical or spheroidal and generally located near the cell walls or nucleus of the host cell.In comparison,the rhizobia in mature infected cells were larger,greater in number,varied in shape,and distributed throughout the nodule cells.The rhizobia in the mature cells also had poly-hydroxy butanoic acid (PHB) and curapos.We hypothesize that spherical rhizobia carry out the function of reproduction in root nodules of Alhagi sparsifolia.This hypothesis is based on the fact that the spherical rhizobia were observed at all stages of the infected host cells development.Furthermore,among the different shapes that were observed for the rhizobia cells,only the spherical rhizobia were seen to reproduce.