戴云山南坡不同海拔森林土壤微生物功能多样性特征及影响因素

Characteristics of microbial functional diversity and its influencing factors of forest soils at different elevations on the southern slope of Daiyun Mountain

土壤微生物作为森林生态系统的主要分解者,参与土壤养分循环,在维持土壤生态系统功能和服务中发挥着重要作用。探讨不同海拔土壤微生物群落结构和功能多样性的季节变化,对维持土壤生态系统稳定具有重要研究价值。以戴云山南坡不同海拔土壤为研究对象(900—1500 m),采用Biolog-ECO微平板法,研究不同海拔土壤微生物群落结构和功能多样性的季节变化(夏季与冬季),揭示驱动戴云山不同海拔土壤微生物季节变化的主要因素。结果表明:(1)夏季海拔1400 m区域土壤微生物的碳源利用最强,微生物活性最高。冬季表现为海拔900 m处土壤微生物对碳源利用最强,活性最高。(2)土壤微生物群落对碳源利用特征的研究表明,夏季与冬季中氨基酸类和羧酸类碳源是7个海拔土壤微生物利用的主要碳源,且夏季碳源利用程度高于冬季。(3)冗余分析表明夏季和冬季戴云山南坡7个海拔土壤微生物群落功能多样性均受土壤环境因子驱动,解释量分别为72.63%和44.12%,均高于地形因子的解释量。(4)土壤温度和全钾含量等因子是驱动夏季土壤微生物群落功能多样性变化的主要因素;土壤全钾、全磷、有效磷含量和坡向是驱动冬季土壤微生物群落功能多样性变化的主要因素。海拔和季节变化通过调节土壤理化性质和土壤酶活性,进而影响森林土壤微生物群落结构和功能多样性。

Soil microorganisms,as the main decomposers of forest ecosystem,participate in soil nutrient cycling and play an important role in maintaining the functions and services of soil ecosystem.It is of great significance to study the seasonal variations of soil microbial community structure and functional diversity at different elevations,which help to maintain the soil ecosystem stability.Soil microbial functional diversity is an important index for reflect the structure,function of soil microbial community,thus influencing the overall dynamic changes of forest community to a certain extent.Therefore,we took the forest soil on the south slope of the Daiyun Mountain(elevation 900—1500 m)as the research object,measured the soil enzyme activity and soil physical and chemical properties at each elevation,and used Biolog-ECO microplate method to explore the seasonal variations of soil microbial community structure and functional diversity(summer and winter seasons)at different elevations.The results showed that:(1)The difference of elevations and forest vegetation types will affect the carbon source utilization of soil microorganisms.in summer,soil microbes at 1400 m elevation had the highest utilization rate of carbon source and microbial activity.In winter,the utilization rate of carbon source and microbial activity at 900 m elevation reached the maximum.(2)The results of carbon source utilization characteristics of soil microbial community showed that amino acids and carboxylic acids were the main carbon sources of soil microbial utilization in summer and winter,and the utilization degree of carbon source in summer was higher than that of winter.(3)Redundancy analysis showed that the functional diversity of soil microbial community was mainly affected by soil environmental factors in summer and winter,and the interpretation was 72.63%and 44.12%,respectively.Moreover,the interpretation was higher than that of topographic factors.(4)The analysis of soil microbial functional diversity index showed that the Shannon Wiener index,Pielou index and Brillouin index of soil microorganisms reached the maximum in the area with an elevation of 1400 m in summer,and the Shannon Wiener index,Pielou index and Brillouin index of soil microorganisms in the area with an elevation of 1300 m in winter were higher than those at other elevations.Soil temperature and total potassium content were the main factors driving the variations of soil microbial community functional diversity in summer,while the main factors were the total potassium content,total phosphorus content,available phosphorus content and aspect in winter.Thus,elevation and seasonal variations affected the forest soil microbial community structure and functional diversity by regulating soil physical and chemical properties and soil enzyme activities.