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从浙江省短枝木麻黄(Casuarina equisetifolia)和细枝木麻黄(C.cunninghamiana)的根瘤中共分离获得14株共生菌株。形态观察表明,菌株具有分枝状菌丝、多腔孢囊、泡囊等典型的Frankia结构、16SrDNA测序结果表明,供试菌株均为Frankia,其中4株属于生理类群A,7株属于生理类群B,3株属于生理类群AB。固氮效应研究表明,菌株均具有固氮酶生物学活性,但菌株之间存在显著差异,其中菌株ZCN192固氮酶活性最强,可达2.897μmol·mg-1·h-1,菌株ZCN199最低,固氮酶活性为0.056μmol·mg-1·h-1。活体固氮试验显示,与阴性对照相比,供试菌株能显著提高苗高、地径和干重,且一般情况下,离体固氮酶活性强的菌株在活体接种时能获得更明显的固氮效应。
A total of 14 strains of commensal strains were isolated from the root nodules of Casuarina equisetifolia and C. cunninghamiana in Zhejiang Province. Morphological observation showed that the strain had typical Frankia structures such as mycelium, multi-cyst and vesicle. The results of 16S rDNA sequencing showed that the tested strains were Frankia, of which 4 belonged to physiological group A and 7 belonged to physiological group B, 3 strains belong to physiological group AB. The results of nitrogen fixation showed that all the strains had the biological activity of nitrogenase, but there were significant differences among the strains. The strain ZCN192 had the highest nitrogenase activity (2.897μmol · mg-1 · h-1), the lowest strain ZCN199, the nitrogenase The activity was 0.056μmol · mg-1 · h-1. In vivo nitrogen fixation test showed that compared with the negative control, the test strains can significantly improve the seedling height, diameter and dry weight, and under normal circumstances, strong in vitro nitrogenase activity of strains in vivo vaccination to obtain more obvious nitrogen fixation effect .