Nutrient amounts of ectomycorrhizae analysed by EDX using ESEM and ICP

Energy-dispersive X-ray (EDX) analysis coupled with an environmental scanning electron microscope (ESEM) was tested as an alternative to the inductively coupled argon plasma (ICP) spectrometer method for nutrient analyses of ectomycorrhizae. The results of EDX-ESEM and ICP were compared for 12 ectomycorrhizal morphotypes collected in beech and Scots pine forests in northern Brandenburg. The amounts of Al, Ca, Mg and S analysed in the outer hyphal layers of the sheath with the EDX-ESEM technique correlated well with the amounts of these elements in the whole mycorrhiza as assessed by ICP. For the elements P and K, no such correlation existed, indicating an uneven distribution of these elements in the ectomycorrhiza. It is concluded that the EDX-ESEM technique could be a useful and reliable tool for the analysis of nutrient elements in ectomycorrhizae, especially for studies focussing on small-scale soil heterogeneity or on infrequent morphotypes.