沙冬青植物群落特征及其根瘤多样性研究

沙冬青是西北荒漠地区珍稀常绿阔叶灌木.该文在其分布区内，综合土壤、水分条件，选定宁夏中卫县沙坡头、内蒙古阿拉善左旗、内蒙古磴口县、内蒙古乌拉特后旗4个地区作为调查样区，研究了沙冬青植物群落和沙冬青根瘤的特征.结果表明:沙冬青植物群落组成较为丰富；因水分、土壤类型及地形差异，不同样区内沙冬青群落成分、结构有一定变化，水分是沙冬青植物群落的决定性生态因子；沙冬青根瘤的最佳采集时间是在结果期之前，根瘤的外部形态呈现多样性，不同样区根瘤的着生部位有差异；水分是根瘤菌侵染沙冬青根系并形成根瘤的主要限制因子；沙冬青群落其他豆科植物的根瘤与沙冬青根瘤具有相似的外部形态. 

Characteristics of plant community of Ammopiptanthus mongolicus and the diversity of its nodules

Ammopiptanthus mongolicus (Maxim.) Cheng f. is an endangered evergreen broadleaved plant in the northwest desert zone of China. Given soil, water and other ecological factors, the authors selected Shapotou area of Zhongwei County in Ningxia Hui Autonomous Region, Alxa Zuogi, Dengkou and Wulate houqi Counties of Inner Mongolia as our research regions, where we studied the characteristics of plant communities and nodules of A. mongolicus. The plant community was rich and the components and structures were varied in different research regions because of the diversity of ecological factors. Water was the decisive ecological factor influencing the components and structures of A. mongolicus plant communities. Nodules morphology of A. mongolicus was varied. The best time to collect nodules should be earlier than the fruiting stage of its host. Nodules were in different root parts at various research regions. Water was the primary ecological factor influencing the infection of rhizobia and the generation of nodules. Nodules isolated from other legumes had similar morphology with those of A. mongolicus.