马仑亚高山草甸土壤可培养微生物数量特征

Quantitative Characteristics of Soil Culturable Microorganisms in Malun Subalpine Meadow

土壤微生物在全球物质循环与能量流动过程中起着决定性作用,并且在生态系统中对环境变化极为敏感.与高寒草甸类似,亚高山草甸同样属于全球气候变化的敏感区,研究该生境不同海拔土壤微生物对于理解气候变化带来的环境影响意义重大.基于此,本研究以山西吕梁山北段马仑亚高山草甸为研究区域,以不同海拔(2600 m、2650 m和2700 m)、不同深度(0~10 cm和20~30 cm)土壤为研究对象,利用不同类型选择性培养基对土壤三大类微生物(细菌、放线菌、真菌)进行计数,并结合土壤理化性质进行相关分析.结果表明:研究区不同海拔、不同深度土壤可培养细菌数量最多,介于2.13×10^(9)~16.53×10^(9)CFU·g^(-1)之间;放线菌次之,介于5.6×10^(7)~15.63×10^(8)CFU·g^(-1)之间;真菌最少,介于6×10^(3)~8.42×10^(5)CFU·g^(-1)之间.且同一海拔0~10 cm表层土壤细菌、真菌数量均显著高于20~30 cm深(P<0.05),放线菌略有不同.相关分析表明细菌数量与土壤温度(ST)显著正相关(P<0.05),放线菌数量与土壤总溶解性固体(TDS)极显著正相关(P<0.01),真菌数量则与土壤pH值极显著正相关(P<0.01),表明限制不同类型可培养微生物数量的关键环境因子不同.研究结果对汾河流域亚高山草甸土壤微生物响应气候变暖具有重要意义.

Soil microbes play a decisive role in the global biogeochemical cycle and are extremely sensitive to environmental changes in ecosystems.Subalpine meadow is a sensitive area of global climate change.Studying soil microorganisms in subalpine meadow is helpful to study the effects of climate change on soil microorganisms and their response characteristics in middle and high altitude areas.Based on this,this study took the subalpine meadow of Malun Steppe in the northern part of Lvliang Mountain as the research area,and took the soil at different altitudes(2600 m,2650 m and 2700 m)and depths(0~10 cm and 20~30 cm)as the research objects.The number of soil bacteria,actinomycetes and fungi was determined using different media,and the physical and chemical properties of soil were determined and analyzed.The results showed that the number of culturable bacteria was the largest at different altitudes and depths,ranging from 2.13×10^(9)~16.53×10^(9) CFU·g^(-1),followed by actinomycetes,ranging from 5.6×10^(7)~15.63×10^(8) CFU·g^(-1),and fungi,ranging from 6×10^(3)~8.42×10^(5) CFU·g^(-1).The number of bacteria and fungi in the surface soil at the same altitude was significantly higher than that at 30 cm depth(P<0.05).Correlation analysis showed that the number of bacteria was significantly positively correlated with soil temperature(ST)(P<0.05),the number of actinomycetes was significantly positively correlated with soil total soluble solids(TDS)(P<0.01),and the number of fungi was significantly positively correlated with soil pH(P<0.01),indicating that the dominant environmental factors limiting the number of different types of microorganisms were different.The results provide theoretical basis and data support for regional subalpine meadow soil microbial response to climate warming.