长年干旱环境对新疆豆科植物根瘤形态结构的影响

对生长在新疆干旱地区的豆科植物苦豆子(Sopara alopecuroides)、新疆黄芪(Astragalus sp.)和新疆野豌豆(Vicia costata)根瘤的形态和结构进行了光学显微镜和电子显微镜观察。根瘤的形态结构受到当地长期干旱环境的影响,根瘤皮层明显地比非干旱区豆科植物根瘤皮层厚。相对厚的皮层为根瘤中心区内的类菌体提供了一个适应范围较大的气体扩散屏障。而在根瘤的中心区,3种豆科植物超微结构差异较大,未发现一种普遍的能与周围干旱生态环境直接相关的根瘤中心区结构特征,表明根瘤皮层结构的改变足以抵御外界干旱的条件。

Influence of long-term aridity on morphological characteristics of legume nodules in Xinjiang.

Nodules of three legume species, Sopora alopecuroides, Astragaous sp. and Vicia costata in Xinjiang are studied on their morphological characteristics with light microscopy and EM. It is found that the shape and structure of nodules are influenced by local environment. Under long-term aridity and high soil temperature, they have a thicker cortex, which as a flexible barrier supports a moderate microenvironment for bacteroids within the nodule. No relationship between ultrastructure of nodule's central zone and dry environment has been found in this study, although there is an obvious structural difference among tested legume species.