Dynamics of de Novo Formation of Amino Sugars in Soil via CSSIA

摘要

Amino sugars are the building blocks of microbial cell walls and have been used widely to assess microbial residues. To have a better insight in the formation dynamics of amino sugars in soil, uniformly carbon-13 (~(13)Cs)-labelled wheat residue of different quality (grain, leaf and root) was amended to two soils under distinct tillage managements. The isotopic composition of individual amino sugars was measured using liquid chromatography — isotope ratio mass spectrometry (LC-IRMS). Maximum formationwas reached within a few days after residue addition. Glucosamine and galactosamine followed dissimilar formation kinetics. The maxima of incorporation of residue C into the amino sugar pools ranged from 1.0 percent for galactosamine to 10.6 percent forglucosamine. Formation rate constants of residue-derived amino sugars ranged from 0.11 to 0.48/d for galactosamine and glucosamine, respectively. In general, larger amounts of amino sugars were formed at a higher rate with increasing plant residue quality. The microbial community of the no-till soil was better adapted to assimilate low quality plant residues (i.e. leaf and root). All together, the formation dynamics of microbial cell wall components was component-specific and determined by residue quality and the soil microbial community.