Abstract:

In this study, the gas exchange and chlorophyll fluorescence in Eremochloa ophiuroides were investigated under drought stress. The results showed that the net photosynthetic rate (Pn) and stomatal conductance (Gs) were significantly decreased after treatment of drought stress, and that intercellular CO2 concentration (Ci) was slightly decreased. These results suggested that the decreased Pn under drought stress was resulted from the stomatal and non-stomatal factors. Drought stress decreased the efficiency of excitation energy captured by PSII (F′v/F′m) and photochemical quenching (qP), thereby resulting in a decreased electron transport flow (ETR). However, the non-photochemical quenching (NPQ) and the excess energy of PSII reaction centers (Ex) were significantly increased after drought stress, which indicated that the partial excitation energy was dissipated by antenna pigments, but the excessive excitation energy could not be dissipated efficiently, thereby resulting in photoinhibition in Eremochloa ophiuroides under drought stress conditions.