凤眼莲根区异养细菌的群落特征与异养活性的研究

STUDIES ON COMMUNITY CHARACTERISTICS AND HETEROTROPHIC ACTIVITY OF HETEROTROPHIC BACTERIA FROM ROOT-ZONE OF WATER HYACINTH

本文研究了凤眼莲根区(根际与根面)异养细菌的群落特征与异养活性。从根区分离出24株优势菌,经鉴定有10个属。其中以气单胞菌属、微球菌属、假单胞菌属、土壤杆菌属和芽孢杆菌属为主要菌属。细菌总数:根际>根面>水体。异养活性以氧化葡萄糖的速率计算。在30℃和pH7.0的条件下。根区菌群都显示较高的活性,且按下列顺序增强:老根区菌群>幼根区菌群>枯根区菌群;而根面菌群活性均大于根际菌群。但在10℃和pH5.0、8.6时,其活性明显地受到抑制。

The community characteristics and the heterotrophic activity of heterotrophic bacteria from the root-zone (rhizosphere and root surface) of water hyacinth (Eichhornia crassipes Solms) were studied. Experimental results are as follows: (1)Twenty-four strains of bacteria were isolated from the root-zone of water hyacinth. They belong to ten genera: Aeromonas, Micrococcus, Pseudomonas Agrobacterium, Bacillus. They are the dominant genera, Chromobacterium Acinetobacter, Eschericia, Vibrio and Serratia. (2)Total bacteriaI number was in the order: rhizosphere>root surface>the water body. (3)Heterotrophic activity was calculated from oxidation rate of glucose in bacteria. The intensity of activity was in the order: bacteria in older roots>bacteria in younger roots>bacteria in roots of withered plants, the activity was higher in bacteria in root surface than in the rhizosphere bacteria. (4)Under the conditions of 30℃ and pH 7.0, all bacteria showed high activities, but their activities were inhibited markedly at a temperature of/0℃, and a pH of 5.0 or 8.6.