Phenolic-rich leaf carbon fractions differentially influence microbial respiration and plant growth

摘要: Phenolics can reduce soil nutrient availability, either indirectly by stimulating microbial nitrogen (N) immobilization or directly enhancing physical protection within soil. Phenolic-rich plants may therefore negatively affect neighboring plant growth restricting the N supply. We used a slow-growing, phenolic-rich alpine forb, Acomastylis rossii, to test hypothesis that carbon (C) fractions stimulate population and growth. generated low-molecular-weight (LMW) fractions, tannin total soluble C from A. rossii measured their effects on respiration of Deschampsia caespitosa, fast-growing, co-dominant grass. Fraction fell into two distinct categories: (1) did not increase killed D. caespitosa plants, (2) stimulated reduced concentration while simultaneously inhibiting root The LMW increased more than tannins. These results suggest phenolic compounds inhibit as well reducing pools available microbes. Both mechanisms illustrate how below-ground influence plants. also examined patterns foliar concentrations among populations across natural productivity gradient (productivity was proxy for competition intensity). Concentrations some phenolics significantly in productive sites where is competitive equal with faster growing caespitosa. Taken together, our contribute important information body evidence indicating quality moving soils have significant performance, potentially associated phytoxic effects, indirect biogeochemistry.