Dynamics of 15N natural abundance in wood-decomposing fungi and their ecophysiological implications

Abstract

Nine species of basidiomycota and one species of ascomycota were grown in an ammonium sulphate media and on beech wood; and the general 15N dynamic patterns of the hyphae were examined. The fungal body initially became depleted in 15N in both the types of incubation. However, the underlying mechanisms were quite different, that is, significant fungal 15N drop on the beech wood is associated with the fungal N reallocation and the uptake of atmospheric ammonia and/or NOx, in addition to isotope fractionation during assimilation. Although the 15N values of the wood-decomposing basidiocarps were generally close to the 15N values of the wood, it does not always indicate that the wood derived N was the sole N source for the fungi throughout the growth periods as shown in our wood-decomposing experiment.