在土壤生态过程对温度、湿度等环境变化的响应方面已有大量的相关研究，但关于调控过程中土壤微生物群落组成对温湿度响应行为的研究还较为缺失。理解土壤微生物群落对土壤温度和湿度的变化的响应规律是准确模拟土壤温室气体排放过程、氮磷周转过程的生物学基础，也是改进全球气候和陆面模型模拟不确定性的一个重要方面。

近期，中国科学院华南植物园博士毕业生周伟平和研究员申卫军等开展了一项全因子设计的室内培养实验，研究温度（10℃、17℃、24℃、31℃、38℃）和湿度（20%、40%、60%、80%、100%田间持水量）的单因子效应以及交互效应，对磷脂脂肪酸法（PLFA）测定的土壤微生物群落组成的影响。

研究结果显示，温度和湿度的单因子效应显著影响几乎所有选定的特征脂肪酸，包括真菌、细菌、革兰氏阳性细菌、革兰氏阴性细菌、放线菌以及细菌胁迫指数。尽管真菌和细菌的比值（F/B）以及革兰氏阳性细菌和革兰氏阴性细菌的比值(G+/G-)均随着温度的升高而增加，但温度和湿度的交互作用对它们的影响不显著。总体上，较高温度下真菌特征脂肪酸的含量较低，湿度变化并没有改变真菌特征脂肪酸的含量。相反，细菌特征脂肪酸的含量在较高温度和中等湿度水平下较高。虽然培养实验过程中，研究人员控制了温度和湿度，但处理引起的土壤理化性质的变化（可溶性有机碳DOC和无机氮ION）只解释了选定的特征脂肪酸变异的18%，其中温度效应的贡献最大（12%）。群落组成变量（真菌、细菌和F/B）和土壤理化性质之间显著相关，表明温度和湿度通过改变土壤底物可利用性间接影响土壤微生物群落组成。该研究认为，在未来全球变暖背景下，南亚热带森林土壤微生物细菌群落的将更为占优，尤其在湿季水分条件比较好的情况下。

相关研究成果发表在European Journal of Soil Science上。该研究得到了国家自然科学基金、“广东特支计划”百千万工程领军人才、国家重点研究发展计划等的资助。（来源：中国科学院华南植物园）

Interactive effects of temperature and moisture on composition of the soil microbial community

Abstract  A wealth of knowledge exists on the response of soil processes to variation in environmental factors such as temperature and moisture, but the response from the soil microbial communities that control these processes remains poorly understood. We carried out a full factorial incubation experiment to investigate the single and interactive effects of temperature (10, 17, 24, 31 and 38°C) and moisture (20, 40, 60, 80 and 100% water holding capacity (WHC)) on composition of the soil microbial community characterized by the phospholipid fatty acids (PLFAs) method. The single and interactive effects of temperature and moisture were statistically significant (P < 0.05) for almost all the selected PLFA signatures, including fungi (F), bacteria (B), Gram-positive bacteria (G+), Gram-negative bacteria (G−), actinomycetes (ACT) and the bacterial stress index (BSI). Although the F/B ratio increased and the G+/G− ratio decreased with increasing temperature, they were not significantly affected by moisture and its interaction with temperature. In general, the concentrations of fungal PLFAs were smaller at higher temperatures, but not altered by changes in moisture. In contrast, the concentrations of bacterial PLFAs were larger at higher temperatures and moderate moisture contents. Although we manipulated temperature and moisture in the incubation, the treatments and the treatment-altered soil properties (dissolved organic carbon (DOC) and inorganic nitrogen (ION)) together explained 18% of the total variation in selected PLFA signatures and the temperature effect contributed the most (12%). Significant correlations between community composition variables (F, B and F/B) and soil properties (DOC and ION) indicated substantive indirect effects of temperature and moisture on the composition of the soil microbial community by altering substrate availability. Our results suggest that soil microbial communities might shift towards a more bacteria-dominated composition under warmer temperatures and moderate moisture conditions in subtropical forest regions.

原文链接：http://onlinelibrary.wiley.com/doi/10.1111/ejss.12488/pdf