Figure 2.

Biplot of principle component analysis (a) for the first two principle components of photosynthetic parameters, ecotypes, drought stress and salicylic acid under non-stress and drought stress treatments. The score plot (b) for the four treatments; control, drought stress, non-stress, salicylic acid and drought stress∗salicylic acid were indicated in blue, green, orange and red, respectively. Abbreviations: Ci, internal-stomatal CO₂ concentration; PWUE, photosynthetic water use efficiency; MC, Carboxylation efficiency; Pn, net photosynthesis rate; gs, stomatal conductance; D, drought stress; SA, salicylic acid; E, respiration rate D, drought stress; SA, salicylic acid; DSA, drought stress∗salicylic acid; DSAE, drought stress∗salicylic acid∗Ecotype. Ecotypes: Kalati (E1), Tazehabad (E2), Fetrezamin (E3), Gavdareh (E4), Baharband (E5) and Telvar (E6).