Study of some physiological and biochemical responses of three wheat (Triticum aestivum L.) cultivars under moisture stress

Drought is one of the most important abiotic stresses which has serious effects on production and qual.ity of crops and increasing global climate changes make this situation more serious. To investigate the physiological responses of wheat cultivars under moisture constraint conditions, a factorial experiment based on randomized complete block design (RCBD) with three replications was conducted at the Research Farm of Agricultural and Natural Resources College of University of Tehran in 2014 -2015. Treatments included three cultivars of wheat recommended for the region (Pishtaz, Sivand and Parsi), and four moisture regimes (70, 90, 110 and 130 mm cumulative evaporation from evaporation pan). There was a significant interaction between the cultivars and moisture regimes in terms of leaf area index and activity of catal.ase enzyme, So that, Sivand cultivar with an average of 436 cm2 had the highest leaf area index and Pishtaz cultivar with 0.12 mg/min, had the highest activity of catal.ase enzyme. The results showed no significant difference in soluble carbohydrate contents. In contrast, Pishtaz cultivar had the highest mean remobilization of soluble carbohydrates and remobilization efficiency (362 mg and 91/1%, respectively). Moisture regimes also had different effects on the studied traits; so that, increasing the irrigation interval from 70 to 130 mm cumulative evaporation resulted in reduction of leaf area, stem length and carbohydrate storage and increase in the spad, the amount of remobilization of soluble carbohydrates, remobilization efficiency and activity of antioxidant enzymes.