【磷同位素稀释法研究微生物有机磷矿化】Marie Spohn Anton Ermak Yakov Kuzyakov.Microbial gross organic phosphorus mineralization can be stimulated by root exudates – A³³P isotopic dilution study.Soil Biology and BiochemistryVolume 65 October 2013 Pages 254–263

Abstract

Phosphorus (P) is one of the most important nutrients for plant growth. While most studies on microbial P mobilization i.e. on mineralization of organic P and solubilization of inorganic P focus on mycorrhiza P mobilization by non-mycorrhizal microorganisms in soil is little explored. In this study we address the question whether root exudates stimulate organic P mineralization by non-mycorrhizal microorganisms. A ³³P isotopic dilution approach was applied to investigate microbial gross P mineralization in top- and subsoil horizons of three forest soils differing in P concentrations (Leptosol Podzol and Cambisol). To simulate the effects of root exudates on microbial gross P mineralization glucose alanine and methionine were added in rhizosphere-relevant concentrations (12 mg carbon (C) g⁻¹ soil organic C). Based on ³³P isotopic dilution we showed that glucose and alanine addition increased gross P mineralization rates up to a factor of 20 and 31 respectively. In contrast methionine had little effect on microbial gross P mineralization rates. Phosphatase activity was increased most strongly due to the addition of alanine and glucose by factors of up to 6 and 4 respectively. Fifteen days after addition of artificial root exudates microbial P concentrations and ³³P recovery in the microbial biomass were only slightly and not consistently changed. In conclusion the results show that alanine and glucose can stimulate microbial gross P mineralization and phosphatase activity and that structure and stoichiometry of root exudates significantly shape the extent of stimulation of microorganisms. Our study indicates that stimulation of non-mycorrhizal microorganisms by root exudates might be an important strategy of plants to increase the availability of P in soils.

【冬季土壤丛枝菌根群落多样性】H. Montero SommerfeldL.M. DíazM. AlvarezC. Añazco VillanuevaF. Matus