Primary and Secondary Metabolites of Vicia faba Plants Cultivated under the Interactive Effect of Drought and Nitric Oxide

Abstract
The improving of drought tolerant of plant is the main target of recent studies over the world. The present investigation deals with using nitric oxide (NO) as a protecting agent against drought stress. NO act a vital role in diverse physiological functions in plants. Presoaking of seeds of two faba bean cultivars (Giza and El-masria) at NO (0.1 mM) for 8 hours and control plants were soaked in distilled water. Plants were cultivated at three levels of water availabilities (100, 70 and 50% FC). Deleterious impact of drought was reduced of chlorophyll a. and reduction of total protein, soluble protein in El-masria 3 cultivar. Whilst drought stress reduced secondary metabolism phenolic compounds but anthocyanins were enhanced by stress. No alleviated the bad impact of water deficiency on cultivars of faba beans by improved the chlorophyll a, carotenoids, soluble carbohydrates, free amino acids, phenolic compounds and anthocyanin. Exogenous application of nitric oxide (0.1 mM NO) may improve the performance of faba bean to be more drought-tolerant.