Abstract
Wheat plants grown in controlled growth chambers were exposed to drought stress (DS) and high temperature (HT) singly and in combination (DS+HT). The effects of these two stresses on net photosynthetic rate (P-N), stomatal conductance (g(s)), intercellular CO2 concentration (C-i), quantum efficiency of photosystem 2 (phi(PS2)) variable to maximum chlorophyll (Chl) fluorescence (F-v/F-m), photochemical (q(p)) and non-photochemical (NPQ) Chl fluorescence, and yield were investigated. Grain yield was decreased by 21 % due to DS, while it was increased by 26 % due to HT. P-N, g(s), C-i, and Chl fluorescence were dramatically reduced to DS, HT, and their interaction, except NPQ which showed an increase due to HT.