*3.4. Photosynthetic Characteristics and Endogenous Ion Content of Marker-Free PDH45 T1 Transgenic Plants under Stress*

The photosynthetic characteristics of transgenic plants were observed and compared to WT and VC plants after 12 d of induction of 200 mM NaCl salt treatment. The photosynthetic rate declined by 33% in WT and 35% in VC plants as compared to *PDH45* marker-free transgenic lines. The net photosynthetic rate, stomatal conductance, intracellular CO2, CO2 release, and transpiration rate were also higher in transgenic lines as compared to the WT and VC plants (Figure 3a–e).

**Figure 3.** Measurement of photosynthetic characteristics and chlorophyll a fluorescence of WT, VC, and *PDH45* marker-free transgenic lines (L4, L7, L8, L11 and L13) under 200 mM NaCl treatment. (**a**) Photosynthetic rate. (**b**) Stomatal conductance. (**c**) Intracellular CO2. (**d**) CO2 release. (**e**) Transpiration rate. (**f**) Photosynthetic yield (Fv/Fm). Values are mean ± SE (*n* = 3). Different letters on the top of bars indicate significant differences at *p* ≤ 0.05 level as determined by Duncan's multiple range test (DMRT).
