The Role and Contribution of Saprotrophic Fungi during Standing Litter Decomposition of Two Perennial Grass Species, \u3ci\u3eSchizachyrium scoparium\u3c/i\u3e and \u3ci\u3eSchizachyrium tenerum\u3c/i\u3e

Abstract

In terrestrial ecosystems, most of the plant biomass produced enters the detrital pool, where microbial decomposers colonize, enzymatically degrade, and assimilate plant litter carbon and nutrients in amounts sufficient to bring about the decomposition of plant litter. Here, I estimated the biomass and production of fungi and microbial respiration associated with decaying Schizachyrium scoparium and Schizachyrium tenerum leaf litter, and constructed a partial organic matter budget estimating C flow into and through fungal decomposers. Significant losses in S. scoparium (57%) and S. tenerum (68%) leaf mass was observed during litter decomposition along with concomitant increases in fungal biomass, which reached a maximum of 36 and 33 mgC/g detrital C in S. scoparium and S. tenerum, respectively. Cumulative fungal production during leaf decay totaled 96 mgC/ginitial detrital C in S. scoparium and 71 mgC/g initial detrital C in S. tenerum, indicating that 17 and 11% of the leaf litter C was converted into fungal biomass, respectively. Next generation sequencing (Illumina) of fungal ITS regions identified several fungal taxa associated with decaying S. scoparium and S. tenerum leaf litter, respectively, with the majority of sequences belonging to the Ascomycota (Dothideomycetes and Sordariomycetes). These findings extend our current understanding of fungal processes in grasslands, which should be incorporated into existing models depicting major biogeochemical pathways