Treseder Kathleen K
Department of Ecology and Evolutionary Biology and Department of Earth System Science, University of California, Irvine, CA 92697, USA.
New Phytol. 2004 Nov;164(2):347-355. doi: 10.1111/j.1469-8137.2004.01159.x.
• Numerous field studies have measured mycorrhizal dynamics under additions of nitrogen (N), phosphorus (P), or atmospheric CO to test the hypothesis that plants should invest in mycorrhizal fungi when soil nutrients are limiting. • Here meta-analyses were used to integrate nutrient responses across independent field-based studies. Responses were compared between ecto- and arbuscular mycorrhizal fungi, and among fertilizer types, methods of measurement, biomes, and lead investigators. Relationships between degree of response and study length, fertilization rates, total amounts of nutrients applied, and numbers of replicates were also tested. • Across studies, mycorrhizal abundance decreased 15% under N fertilization and 32% under P fertilization. Elevated CO elicited a 47% increase. Nitrogen effects varied significantly among studies, and P effects varied significantly among lead investigators. Most other factors did not affect mycorrhizal responses. • These results support the plant investment hypothesis, and suggest that global standing stocks of mycorrhizal fungi may increase substantially under elevated CO but decline moderately under P additions. Effects of N deposition may be difficult to predict for individual ecosystems, with a slightly negative influence overall.
• 许多实地研究在添加氮（N）、磷（P）或大气二氧化碳的情况下测量了菌根动态，以检验以下假设：当土壤养分有限时，植物应向菌根真菌投入资源。
• 在此，我们进行了荟萃分析，以整合独立实地研究中的养分响应情况。比较了外生菌根真菌和丛枝菌根真菌之间的响应，以及肥料类型、测量方法、生物群落和主要研究者之间的响应。还测试了响应程度与研究时长、施肥率、养分施用总量和重复次数之间的关系。
• 在各项研究中，施氮条件下菌根丰度下降了15%，施磷条件下下降了32%。二氧化碳浓度升高导致菌根丰度增加了47%。氮的影响在不同研究中差异显著，磷的影响在主要研究者之间差异显著。大多数其他因素并未影响菌根响应。
• 这些结果支持了植物投入假说，并表明在二氧化碳浓度升高的情况下，全球菌根真菌存量可能会大幅增加，但在施磷情况下会适度下降。对于单个生态系统而言，氮沉降的影响可能难以预测，总体上有略微的负面影响。
