干旱胁迫对假俭草气体交换和叶绿素荧光特性的影响

以假俭草为实验材料，研究干旱胁迫对假俭草气体交换、叶绿素荧光的影响。结果表明，干旱胁迫使假俭草净光合速率（Pn）和气孔导度（Gs）明显下降，胞间CO2浓度（Ci）也略有下降，说明Pn的下降是气孔因素和非气孔因素共同作用的结果。干旱胁迫使得PSⅡ反应中心捕获激发能效率（F′v/F′m）和光化学猝灭（qP）降低，从而引起电子传递速率（ETR）的降低。干旱胁迫后，假俭草非光化学猝灭（NPQ）和反应中心过剩激发能（Ex）明显上升，说明假俭草天线色素尽管可以耗散部分能量，但不能及时地有效地耗散过剩激发能，从而使假俭草发生明显的光抑制。

Effects of drought stress on gas exchange and chlorophyll fluorescence characteristics in Eremochloa ophiuroides

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.