ESJ58 一般講演（ポスタ-発表） P1-072

Response of leaf gas exchange to warming, precipitation and nitrogen addition in a dominant species, Stipa krylovii, semiarid temperate steppe

*BORJIGIDAI, A., XI, Y., LI, Y. （Minzu Univ.）, GAO, Q. （IEDA-CAAS）, BAI, W., WAN, S., LI, L. （IB-CAS）, YU, G. （IGSNRR-CAS）, HOSHINO, B. （Rakuno Gakuen Univ.）

Influences of global change, such as warming, precipitation and nitrogen (N) addition, on plant growth and ecosystem function have become major concerns, but in leaf level how plant gas exchange changes with warming, precipitation and N addition in the field is poorly understood. Therefore, we conducted a field manipulative experiment of warming, precipitation and N addition on temperature dependence of photosynthetic parameters in a dominant species, Stipa krylovii, a temperate steppe in northern China. We focused on stomatal conductance (g_s), intercellular CO₂ concentration (C_i), maximum rate of Rubisco activity (V_cmax), maximum rate of electron transport (J_max), activation energy of V_cmax (E_av), activation energy of J_max (E_aj) and dark respiration (R_d) which potentially affect temperature dependence of photosynthetic rates. In present study, we found that temperature dependence of photosynthesis was changed by climatic factors and plant nitrogen status, which differed between warming, precipitation and N addition.