The phenotypic plasticity, biomass, morphology, chlorophyll content and reproductive allocation (RA) of Mosla chinensis were studied in five soil water treatments, which were the relative water content (RWC) of holding capacities (WHC) in soil (100%, 80%, 60%, 40% and 30%). The root, shoot, branch and leaf biomass were positively correlated with RWC increase from 30%～80% of WHC; however, biomass declined at 100% WHC. Highest ratios of fresh weight to biomass in branch and leaf were observed at 80% WHC. M. c...