帽儿山针阔混交林及纯林土壤碳代谢微生物群落特征研究

【目的】评价帽儿山地区纯林与混交林(红皮云杉纯林、长白落叶松纯林、胡桃楸和红皮云杉混交林、胡桃楸和长白落叶松混交林、水曲柳和红皮云杉混交林、水曲柳和长白落叶松混交林)土壤生态系统中参与土壤碳代谢的微生物群落特征。【方法】借助Biolog^MT技术,比较了纯林与混交林之间根际土壤微生物对不同碳源类型的利用情况。【结果】不同林型土壤微生物平均颜色变化率(AWCD)呈现阔叶林高于针叶林,胡桃楸针-阔混交林型中针叶林土壤微生物AWCD值优于与水曲柳混交林型。胡桃楸针-阔混交林中,针叶林的Shannon指数显著地高于水曲柳针-阔混交林。Simpson优势度指数与Shannon多样性指数变化趋势较为相似。羧酸、氨基酸和糖类这3类碳源是导致微生物代谢呈现差异的主要碳源。长白落叶松、红皮云杉与水曲柳混交后对糖类、羧酸和氨基酸3种主要碳源的利用程度均有所下降,可能是导致AWCD值较低的原因之一。【结论】胡桃楸针-阔混交林比水曲柳针-阔混交林以及针叶纯林更有利于土壤微生物群落的碳代谢功能发挥。

The carbon metabolism characteristics and diversity of soil microbial communities from pure or coniferous and broad-leaved mixed forests in the Maoer Mountain region

【Objective】The characteristics of soil carbon metabolism of microbial communities were evaluated from pure and mixed forests(a pure stand of Picea koraiensis and one of Larix olgensis, mixed stands of P. koraiensis and Juglans mandshurica, P. koraiensis and Fraxinus mandshurica, L. olgensis and J. mandshurica, and L. olgensis and F. mandshurica)in the soil ecological system of the Maoer Mountain region. 【Method】By using Biolog^MT technology, this study compared the utilization of different carbon sources by rhizosphere microorganisms in pure and mixed plantations. 【Result】The average well color development(AWCD)of soil microorganisms in broad-leaved forests was higher than that of the coniferous forests, and the AWCD of soil microorganisms in mixed forests of J. mandshurica was higher than that of the coniferous and the broad-leaved mixed forests of F. mandshurica. The Shannon index of coniferous J. mandshurica mixed forests was significantly higher than that of the F. mandshurica mixed forests(P<0.05). The Simpson index trend was similar to that of the Shannon index. Carboxylic acids, amino acids and sugars were the three main carbon sources which led to the difference in soil microbial metabolism. After L. olgensis and P. koraiensis were mixed with F. mandshurica, their ability to utilize different carbon sources decreased; this also caused the AWCD decreasing. 【Conclusion】The mixed forests of J. mandshurica provided more favorable conditions to improve the carbon metabolism of soil microbial communities than mixed forests of F. mandshurica or coniferous forests.