Response of proline, soluble sugars and antioxidant enzymes in wheat (Triticum aestivum L.) to different irrigation regimes in greenhouse condition

To evaluate the response of proline and soluble sugars content, catalase (CAT) and ascorbate peroxidase (APX) activity in wheat leaves to different irrigation regimes at two growth stages, a greenhouse factorial experiment was conducted in a completely randomized design (CRD) with three replications. The factors consisted of four different irrigation regimes as 100% (I0), 75% (I1), 50% (I2) and 25% (I3) of field capacity and growth stages: 50% emergence to booting stage (GS1) and booting stage to physiological maturity (GS2). Fresh leaf tissues were used to determine proline and soluble sugars content, CAT and APX activity. According to the results, irrigation regimes had significant effect on proline content, soluble sugars and APX activity, but no significant differences were detected among irrigation regimes for catalase (CAT) activity. Limited irrigation increased proline concentration and total soluble sugars in leaves. None of studied traits were affected by growth stages. Interaction between irrigation regimes and growth stages was not significant for all studied traits. Results indicated that the highest proline content (12 μmol/g DW), total soluble sugars (49 mg/g DW) and APX activity (42 μmol min-1 g-1 FW) were related to irrigation at 25% of field capacity (I3). It was concluded that proline and soluble sugar levels were increased in wheat leaves under deficit irrigation regimes