Under field conditions, drought stress is gradually processed,
and stomatal closure is the first response of photosynthesis
(Medrano et al., 2002). Stomatal closure induces over-reduction in
electron transport chain due to the suppression of energy utilization
in the process of photosynthetic CO2 fixation, and increases the
generation of reactive oxygen species (ROS) (Apel and Hirt, 2004).