Monosaccharide composition of primary cell wall polysaccharides as a developmental level indicator of biological soil crusts

The relative abundances of microbial community, chlorophyll content, and exopolysaccharides are used as indices in assessing the developmental level of biological soil crusts (BSCs). However, the macromolecular polysaccharide of primary cell wall (PCW) is rarely mentioned. In this study, the monosaccharide composition of PCW polysaccharides were used to assess the developmental level of BSCs with accurate crusted ages on a large time scale (9–61 years), and chlorophyll contents, total carbohydrates, moss abundances, and cyanobacterial abundances were investigated. Relative moss abundances were significantly and positively correlated with the increase in crusted age; chlorophyll content; and the percentage of monosaccharides, such as mannose, arabinose, and galactose, in PCW polysaccharides. Relative cyanobacterial abundances were significantly correlated with monosaccharides, such as fucose, glucose, and ribose. These results suggested that the monosaccharide percentage of PCW polysaccharides could be a good developmental level indicator for assessing the developmental level and succession phage of BSCs.