羊奶果不同发育阶段根瘤的细胞结构及固氮、吸氢活性

Cellular Structure of Root Nodules of Elaeagnus conferta Roxb. and Nitrogen Fixation Activity

摘要:

比较羊奶果根瘤三个不同发育阶段的显微、亚显微结构和固氮、吸氢活性的差异,探讨了根瘤结构与功能的关系。结果表明:早期侵染方式为皮层细胞间隙侵染,此期的内生菌是一种分枝、具隔膜的菌丝体,早期侵染细胞有脂体存在。成熟根瘤含菌细胞明显多于幼瘤和衰老瘤。成熟根瘤具有大量泡囊,成熟泡囊具分隔、双层壁结构。衰老瘤泡囊分隔消失,不呈双层壁结构。成熟根瘤的固氮、吸氢活性明显高于幼瘤和衰老瘤。

Abstract:

The ultrastructure of root nodules of Elaeagnus conferta Roxb. and the activities of nitrogen fixation and hydrogen uptake were studied, The results show that Frankia hyphae exist at early stage in intercellular space in nodule cortex. The filamentous hyphae are branched with septa. Lipid bodies are distributed in infected young cells. The number of infected cells in mature nodules is much larger than that of young and senescent nodules. Apical endophytic hyphae swell to form lots of vesicles which are septate and double-walled. Vesicles are suggested to be importatant in nitrogen fixation. In senescent nodules, the vesicles disintegrate. Nitrogen fixation and hydrogen uptake activities in mature nodule is much higher than that in young and senescent nodules.