5 CONCLUSIONS
In conclusion, the damage to PS II observed after the heat and drought
stress was attributed to blocked linear electron transport caused by a
decrease in the PQ pool. CEF protects PS II from heat and
drought-induced photo-inhibition. Exogenous trehalose alleviated the PS
II photo-inhibition caused by heat and drought stress by promoting CEF.
The water-water cycle as well as CEF may play a key role protecting PS
II under heat and drought plus heat stress by increasing ΔpH and ATPase
activity.