Antioxidant Potential and Oxidative Stress Markers in Wheat (Triticum aestivum) Treated with Phytohormones under Salt-Stress Condition

The interactive effects of indole acetic acid (IAA) or salicylic acid (SA) (0.5 and 0.1 mM, respectively) as shoot spraying on NaCl stressed wheat (Triticum aestivum L.) plant organs grown in experimental pots under different salinity levels (0, 50, 100, 150 and 200 mM NaCl, respectively) were studied. The antioxidant enzymes as catalase (CAT), peroxidase (PX), and ascorbate peroxidase (APX), photosynthetic pigments, reducing sugars, proteins, amino acids (AA), and proline (Prol) contents in spike, shoot and root of salt-stressed plants were the most affected parameters, specially at high salinity levels (150 and 200 mM NaCl). Treatments with 0.5 mM of IAA or 0.1 mM of SA on stressed wheat organs mitigated the detrimental effect of NaCl. Phytohormones improved salt tolerance in wheat organs activating antioxidant enzymes, increasing photosynthetic pigments and enhancing the accumulation of non toxic metabolites. The magnitude of increase was more pronounced in SA than in IAA treated plants, and the spike was the most accumulator organ of non toxic metabolites compared to shoot and root. Finally, SA and/or IAA treatments prevent the negative effects of salt stressed wheat and these could be adopted as a potential growth regulator or antioxidant to improve wheat growth under moderate salt levels. c 2013 Friends Science Publishers