象草根际土壤微生物生理群数量特征研究

目的]查明象草根际微生物生理群的分布特点。方法]利用选择性培养基，采用涂抹平板法和稀释法对象草根际土壤微生物生理群（氨化细菌、硝化细菌、反硝化细菌、芽孢杆菌等）数量时空分布特征进行研究。结果]象草根际各微生物生理群的数量具有明显的根际效应，均为根际〉非根际，但根面与根区相比，根面好气性微生物较多，而根区嫌气性微生物较多；同一根际部位，不同微生物生理类群数量也有差异；象草根面纤维素分解和氮的固定主要是好气性菌起作用，根区纤维素分解主要是嫌气性纤解菌起作用，固氮为好气性自生固氮菌和嫌气性自生固氮菌共同起作用。结论]象草的根际区域不同，微生物生理群种类不同，其数量时空分布动态也不同。

Studies on the Quantitative Characteristics of Microbial Physiological Population in the Rhizosphere Soil of Elephant Grass

Objective] The study was to find out the distribution characteristic of microbial physiological population from elephant grass rhizosphere soil.Method] Population spatial and temporal distribution characteristic of microbial physiological groups such as ammonifying bacteria,nitrobacteria,denitrobacteria,bacillus from the elephant grass rhizosphere soil were investigated by using selective media and with the plate count and MPN methods.Result] Quantity of microbial physiological groups from the elephant grass rhizosphere soil had obvious rhizosphere effect,being rhizosphere> outrhizosphere,but the comparison between rhizoplane and ectorhizosphere showed that there were more aerobic microorganisms in rhizoplane and wore anaerobic microorganisms in ectorhizosphere.There were discrepancy in different microbial physiological groups within same rhizosphere region.Aerobic microbes played an important role in cellulose degradation and nitrogen fixation in rhizoplane,and the anaerobic cellulolytic microbes played an important role in cellulose degradation and the aerobic and anaerobic abiogenous azotobacter played the interaction role in nitrogen fixation in ectorhizosphere.Conclusion] As the rhizosphere areas of elephant grass were different,the kinds of microbial physiological groups were different and their population spatial and temporal distribution was also different.