多花黑麦草根际微生物研究

Studies on Italian Ryegrass Rhizosphere Microbes

采用选择性培养基平板梯度稀释培养,测定了不同肥力不同品种多花黑麦草(特高、长江2号和沃土)根际细菌、真菌、放线菌和三类促生细菌的数量,并根据真菌的培养形态和显微形态等,参考相关资料进行了真菌的分类和鉴定。结果表明:肥沃土壤中多花黑麦草根际细菌、真菌和放线菌及三类促生细菌的数量均高于贫瘠土壤;肥沃土壤中多花黑麦草不同品种间根际细菌、放线菌数量差异较大,而贫瘠土壤中多花黑麦草品种间差异不显著,不同肥力土壤中的真菌数量品种间均差异不显著。多花黑麦草根际三类促生细菌中溶磷细菌的数量最多,其次是自生固氮菌,硅酸盐细菌的数量最少;溶磷细菌中,有机磷细菌的数量远远多于无机磷细菌的数量。不同品种对根际微生物数量分布也有影响,不同品种间细菌和放线菌的数量差异较大,真菌数量差异不显著。从多花黑麦草根际分离到的真菌分别属于11个属,根际真菌的种类、多样性、丰富度、均匀度及优势度指数也随土壤肥力及品种不同而有差异。

The rhizosphere soil were obtained by five point sampling method from Italian ryegrass soil with different fertilities in Rongchang county of Chongqing city.Rhizosphere bacteria,fungi and actinomyces in samples from fertile and infertile soil were isolated and cultivated by the plate cultivation method with selective media.The results showed that the quantities of bacteria,fungi,actinomycetes and azotobacter,phosphobacteria,potassium-bacteria in fertile soil were more than in infertile soil.In soil of the same fertility,the quantity of bacteria was the largest,that of actinomyces the second,and that of fungi the least.In fertility soil,the quantity difference of bacteria and actinomycetes of different varieties of Italian ryegrass were larger than infertile soil,but the quantity of fungi was not.Among three PGPR bacteria,the quantity of phosphobacteria was the largest,that of azotobacter the second,and that of potassium-bacteria the least.To phosphobacteria,the quantity of organic phosphate bacteria was larger than inorganic phosphate bacteria.The Italian ryegrass varieties also influenced rhizosphere microbes＇quantity.Bcteria and actinomyces＇quantity of different Italian ryegrass had bigger difference,but the quantity of fungi had not significant difference.Fungi isolated from all Itanlian ryegrass rhizosphere soil belonged to eleven genera： Cladosporium,Penicillium,Fusarium,Rhizopus,Gliocladium,Sclerotium,Pythium,Pullularia,Periconia,Aspergillus,Alternaria.As the soil fertilities and varieties of Italian ryegrass were different,the population spatial and temporal distribution were different and their diversity index,richness index,evenness index and domination index were also different.