Exogenously Applied H2O2 Promotes Proline Accumulation, Water Relations, Photosynthetic Efficiency and Growth of Wheat (Triticum aestivum L.) Under Salt Stress

Aim: To determine the role of hydrogen peroxide (H2O2) in the alleviation of salt stress in wheat (Triticum aestivum L.).
Design of the Study: Wheat plants were grown with or without 100 mM NaCl and were treated with 0, 50 or 100 nM H2O2 treatments.
Place and Duration of Study: The experimental work was carried out in the naturally illuminated green house at the Department of Botany, Aligarh Muslim University, Aligarh, India between November to December, 2012.
Methodology: Plants were sampled at 30 days after seed sowing to determine physiological, biochemical and growth parameters.
Results: Treatment of plants with H2O2 significantly influenced the parameters both under non saline and salt stress. The application of both 50 and 100 nM H2O2 reduced the severity of salt stress through the reduction in Na+ and Cl- content; and the increase in proline content and N assimilation. This resulted in increased water relations, photosynthetic pigments and growth under salt stress. However, maximum alleviation of salt stress was noted with 100 nM H2O2 and 50 nM H2O2 proved less effective. Under non saline condition also application of H2O2 increased all the studied parameters.
Conclusion: The treatment of 100 nM H2O2 maximally benefitted the wheat plants under non saline condition and alleviated the effects of salt stress. The treatment of H2O2 increased proline content which might help increased photosynthetic pigments and growth under salt stress. The mechanism of proline metabolism by which H2O2 treatment may protect against salt stress will be investigated further.