内蒙古荒漠草原不同生态位三种植物根系分泌物的微生态效应研究

Microecological Effects of Root Exudates from Three Plant on Different Ecological Niche in Inner Mongolia Desert Steppe

以内蒙古四子王旗荒漠草原群落中短花针茅(Stipa breviflora)、无芒隐子草(Cleistogenes songorica)和银灰旋花(Convolvulus ammannii) 3种牧草为研究对象,分析了不同收集时间段3种牧草根系分泌物收集液对草原土壤理化性状及微生物数量的影响.结果表明,随牧草根系分泌物收集时间的增加,供试草原原位土壤中的细菌、真菌和放线菌数量显著增加;供试土壤中的有机质、有效氮和有效磷含量显著增加、土壤pH值显著下降,土壤含水量无显著变化;建群种短花针茅的根系分泌物对土壤微生物和土壤理化性状的影响作用强于优势种无芒隐子草和伴群种银灰旋花.

In this research,we collected the root exudates of three plants, Stipa breviflora,Cleistogenes songorica and Convolvulus ammannii ,in Inner Mongolia desert steppe by hydroponics and applied them to the soil of the grassland to study the microecological effects of them on soil physicochemical properties and microbial number of soil.The results showed that the root exudates of the three plants significantly promoted the number of bacteria,fungi and actinomycetes in the desert soil.Meanwhile,the root exudates also increased the contents of soil organic matter,available nitrogen and available phosphorus,and decreased the soil pH value significantly.No significant effect on soil water content was found in the research .With regard to the three plant species,we found out that the effect of root exudates of constructive species, Stipa breviflora ,was better than Cleistogenes Songorica and Convolvulus ammannii ,which were dominant and associated species respectively,on soil microbial and physicochemical properties.