The role of osmoprotectants and antioxidant enzymes in the differential response of durum wheat genotypes to salinity

This study aims to investigate the importance of accumulation of osmoprotectants and activities of some key antioxidant enzymes in genotypic variation (GV) observed among durum wheat genotypes in response to increasing NaCl salinity (0-200 mmol/L) at seedling stage. Germination and seedling growth traits of all the genotypes were significantly decreased by salinity. Mohamed Ben Bachir, the more salt-tolerant genotype, exhibited the lowest reduction in final germination percentage (FGP, <18%) and seedling growth (<60%, based on dry biomass), the lowest increase in proline (PRO) and water soluble carbohydrates contents but the highest increase in catalase (CAT) and ascorbate peroxidase (APX) activities. Correlation and principal components analysis revealed that the most important variables distinguishing salt tolerant vs. salt non-tolerant genotypes were root to shoot ratio (R/S, 36.1%), CAT (30.6%), APX (12.5%) and FGP (5.74%). Although PRO and WSC could play a key role in salt tolerance by mediating osmotic adjustment, these compounds do not seem to be significantly involved in genotypic variation (GV) for salinity tolerance in durum wheat.