*4.2. Determination of Photosynthesis and Leaf water Relation*

The physiological parameters such as Pn, Tr, Gs and Ci were measured according to our previous study [87]. The chlorophyll content was measured spectrophotometrically according the method of Sheteiwy et al. [88]. The values of Ψw, WUE and RWC were measured according to our previous study [87]. The Ψs was measured according to the method of Ahmed et al. [8].

### *4.3. Biochemical Analysis*

For further investigation regarding the potential role of GABA priming to alleviate the oxidative stress induced by salinity and osmotic stress, the antioxidant enzymes, i.e., SOD, CAT and APX were measured according the method of Sheteiwy et al. [88]. GR and total soluble sugars were measured according the method of Sheteiwy et al. [89]. The starch content and total soluble proteins were measured according to the method of Sheteiwy et al. [90].
