The stoichiometry of nitrogen (N) and phosphorus (P) in terrestrial plants varies over large spatial scales in association with temperature and precipitation regimes that are expected to shift spatially under various global change scenarios.The details of this coupling of plant stoichiometry to elemental cycling deserve renewed attention.In this study,an endemic and typical psychrophyte,Corydalis hendersonii,which is dominant in the alpine region of the Tibetan Plateau,was investigated in situ across the plateau to determine how temperature,precipitationand and soil nutrients affect N∶P stoichiometry in leaves and roots.Our analyses highlight that nutrient reserves and accumulation are the important adaptive strategies in C.hendersonii for maintenance and growth in extreme environments,where highly intermittent nutrient availability strongly shifts the patterns of N∶P stoichiometry.The effects of environmental variables on N and P concentrations in leaves and roots were associated with a shift in the growth of above-and belowground biomass and a greater plasticity of allocation of N and P to leaves and roots rather than consistent selection for coordinated leaf and root nutrient traits.In general,warming can significantly decrease the N concentrations and N∶P ratios in leaves and roots and increase soil total nitrogen (STN) and soil total phosphorus (STP).Conversely,drought can dramatically increase N and P concentrations and N∶P ratios in the leaves and roots,in particular in roots,but decrease the STN and STP contents across the Tibetan Plateau.Our findings also support the temperature-plant physiological hypothesis and the biogeochemical hypothesis.