Photosynthetic pigments, antioxydant enzymes and leaf osmotic potential of ten durum wheat (Triticum durum) genotypes: impact of water stress
Osmotic adjustment, photosynthetic pigments and changes in antioxidant enzyme activities were evaluated in ten durum wheat (Triticum durum) genotypes under water stress conditions. The wheat seedlings germinated in hydroponic conditions in a growth chamber. Water deficit was performed at the fourth and fifth leaf stages using a polyethylene glycol (PEG 6000) solution (-0.49 MPa). Osmotic potential as well as total chlorophyll (Chl a+b) and carotenoid (Car) contents were investigated. Electrophoretic analyses were performed for three antioxidant enzymes: superoxide dismutase (SOD), guaiacol peroxidase (GPOX) and catalase (CAT) using native polyacrylamide gel electrophoresis (PAGE). The results obtained show a reduction in leaf osmotic potential and a decrease in Chl a+b and Car contents under water stress conditions. However, there are significant differences between the genotypes studied in their response to the treatment. PAGE showed an increased intensity in the enzymes studied and the appearance of additional isoforms, including one CAT and three SOD, under stress conditions. These differences in water stress response could be useful and reliable indices for the selection of tolerant durum wheat genotypes.