Similar release pattern of two major groups of primary metabolites in root exudates of four coexisting canopy species

Abstract

Both quantity and quality of root exudates regulate the dynamic of soil organic matter (SOM). However, how chemical composition of root exudates varies among woody species is less known. In this study, we identified two major groups of primary metabolites, namely monosaccharides and organic acids, in the root exudates of two dominant species and two of their congeneric species in a temperate forest. Monosaccharides and seven types of organic acids constituted 38.7% and 22.7% of total carbon (C) in the root exudates, respectively. The release pattern of our target metabolites exhibited no difference among target species. Furthermore, C flux rates of two most abundant primary metabolites we detected, namely monosaccharides and citric acid, exhibited positive relations with total root-exudate C, and the slopes were not different among target species. The similar release pattern of target primary metabolites may induce similar microbial response to root-exudates among target species in SOM dynamic.