Phenotypic Plasticity of Two Stipa in Grassland Responses to Elevated CO2 and Precipitation Change

Elevated atmospheric CO2 concentration and precipitation change affect plants’ survival and thriving. Phenotypic plasticity can show plants adaptability to varying environment. Physiological plasticity reflects plants capacity to open areas, and morphological plasticity reflects capacity to survive and grow. In this study, we simulated combined effects of elevated CO2 and precipitation change on the phenotypic plasticity of two Stipa species: Stipa grandis and Stipa breviflora. Our results indicated that plasticity of physiology was higher than plasticity of morphology under either ambient or elevated CO2 concentration in both Stipa species. S. breviflora showed higher plasticity index of physiological (PIp) and plasticity index of morphological (PIm) than S. grandis under elevated CO2 concentration. Therefore, we speculate that S. breviflora is more adaptable than S. grandis under high CO2 concentration in the future. Elevated atmospheric CO2 concentration and simultaneous precipitation change is advantageous to S. breviflora distribution expansion, nonetheless, the changing environments also favor the competitive ability of S. grandis.