海拔对黄山松阔叶混交林土壤微生物功能多样性的影响

【目的】研究浙江凤阳山黄山松阔叶混交林土壤理化性质以及微生物对碳源的利用状况,明确海拔变化对黄山松阔叶混交林林地土壤微生物功能多样性的影响。【方法】以黄山松在凤阳山的主要海拔分布范围(1 000~1 800 m)为准,选取中海拔(1 200 m)、中高海拔(1 500 m)、高海拔(1 800 m)3个海拔梯度,在每个海拔梯度的阳坡内选取排水较好、坡度较缓、长势适中的3个标准样地(20 m×20 m),采用Biolog Eco法研究该林分类型在不同海拔梯度下土壤微生物对碳源的利用特征,同时对土壤微生物利用各类碳源的特性进行非度量多维标度(NMDS)排序,进一步分析土壤微生物对各类碳源的利用情况。【结果】(1)在中高海拔处的土壤微生物活性最强,土壤微生物多样性指数随着海拔变化并无显著变化(P0.05);(2)研究区内土壤微生物主要利用的碳源类型为碳水化合物(CH)、氨基酸类(AA)、聚合物类(PM),各海拔处土壤微生物对酚酸类(PA)和胺类(AM)碳源的利用率均较低,而对羧酸类(CA)碳源的利用存在显著差异;NMDS排序显示,随海拔变化,土壤微生物对6类碳源的利用出现显著差异(P0.05);(3)土壤养分含量在中高海拔处最大,冗余分析显示土壤理化性质与土壤微生物对碳源的利用之间有较强的相关关系。【结论】中高海拔处土壤微生物对各类碳源的利用率都较高,土壤理化性质的改变是影响土壤微生物对碳源利用的重要因素。

Soil microbial characteristics of Pinus taiwanensis and broad-leaved mixed forest at different altitudes in Fengyang Mountain

Objective] To study the soil physicochemical properties and the use of carbon sources by microorganisms,we investigated the effects of altitude change on soil microbial functional diversity in the Pinus taiwanensis broad-leaved mixed forest of Fengyang Mountain.Method]Using the main distribution range from 1 000 m to 1 800 m of Pinus taiwanensis in Fengyang Mountain as the standard,we chose three altitude gradients,respectively:medium altitude (1200m),middle-high altitude (1 500 m),and high altitude (1 800 m).We selected the best site in each altitudinal gradient drainage,on a sunny,gentle gradient slope,with slow,moderate growth in three standard plots (20 m×20 m).We applied the method of Biolog Eco Plate to study the carbon utilization of soil microorganisms in this type of forest at different altitude gradients.We used non-metric multidimensional scaling (NMDS) to order and further analyze the use of various carbon sources by soil microbes.Result] ① The soil microbial activity was the highest at the middle-high altitude,whereas the soil microbial diversity index did not change significantly with altitude (P＞0.05).② In the study area,the main types of carbon source used were carbohydrates (CH),amino acids (AA),and polymers (PM).The utilization rate of phenolic acids (PA) and amine (AM) carbon sources varied with altitude.There were significant differences in the utilization of the carbon source carboxylic acid (CA) at different altitudes.The NMDS ordination showed that the use of six carbon sources varied with the change in altitude (P＜0.05).③The soil nutrient content was the highest in the middle-high altitude areas,and the redundancy analysis showed that there was a strong correlation between the physicochemical properties of soil and the utilization of carbon.Conclusion] In the middle-high altitude areas,soil microbes have a strong effect on the utilization of various carbon sources,and the change in soil physical and chemical properties is an important factor affecting the utilization of carbon sources.