Interactions between needles of Pinus resinosa and ectomycorrhizal fungi

Relatively little is known about the factors controlling ectomycorrhizal fu ngal communities. One possible factor is forest litter chemistry. In a seri es of experiments we demonstrated that the growth of ectomycorrhizal fungi able to colonize red pine (Pinus resinosa Ait.) are differentially affected by red pine needles and needle chemical components. For example, water ext racts of pine needles stimulated the growth of Suillus intermedius (Smith & Thiers) Smith & Thiers and inhibited the growth of Amanita rubescens Pers. Catechin and epicatechin gallate, components of the water extract, acted s imilarly to the extract. The volatile compounds alpha- and beta-pinene also had differential effects on the growth of the various species of ectomycor rhizal fungi. Our results suggest that forest litter chemistry has the pote ntial differentially to affect the growth of ectomycorrhizal fungal species and so could affect the structure of ectomycorrhizal fungal communities.