Maintenance of tissue water status helps the plants to avoid the dehydration and protects the carboxylati on and other enzymes from inactivation and denaturati on (Anjum et al., 2012). By con-trast, a strong decrease in the photosynthetic rate in 5/cultivar,8/cultivar plants, and ungrafted plants, along with a decrease in RWC (a weak osmotic adjustment), and a decrease in Fv/Fo was observed under water stress.