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 (PI_p) and plasticity index of morphological (PI_m) 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.