Growth and Solute Composition in Two Wheat Species Experiencing Combined Influence of Stress Conditions1

The effects of environmental stress combinations on the soluble metabolites were investigated in several cultivars of Triticum aestivum and T. durum. The seedlings grown at optimum (24/16°C), low (5/–5°C) (LT), and high (40/30°C) (HT) day/night temperature conditions were exposed to waterlogging, drought, and salinity (0.7% NaCl, w/w) stresses for six days. Root and shoot fresh weight significantly decreased under waterlogging, drought and salt stresses. Fresh weight was most reduced at severe drought + HT combinations. The lowest relative water content was found under drought stress + HT combination. Soluble carbohydrate (SC) contents increased under LT conditions, but decreased under HT conditions. Under HT + salt combinations, T. aestivum genotypes showed higher SC content thanT. durum genotypes. Proline content significantly increased in the case of water deficit and salt stress. Under drought and salt stresses, T. aestivum genotypes had lower proline contents than T. durum genotypes. These results indicate that biochemical responses to drought, waterlogging, and salt stresses were significantly changed in wheat seedlings under LT and HT conditions.