Soil and foliar applications of zinc sulfate and iron sulfate alleviate the destructive impacts of drought stress in wheat

Water deficit is a major abiotic stress that devastatingly affects wheat growth and production, particularly in arid environments. Moreover, drought is expected to become more frequent and severe owing to current climate change. Consequently, it is necessary to find affordable approaches to enhance drought tolerance, principally for important crops such as wheat. The present study is a controlled pot experiment which was performed to investigate the efficiency of soil application or exogenous foliar of zinc sulfate (ZnSO4·7H2O) or/and iron sulfate (FeSO4·7H2O) to attenuate the deleterious impacts of drought stress in winter wheat. The plants were exposed to water deficit (40% field capacity) versus well-watered conditions (80% field capacity). Drought stress significantly declined relative water content and leaf chlorophyll content while increased proline accumulation, water saturation deficit, and water uptake capacity relative to well-watered conditions. Moreover, leaf characters (number and area) significantly diminished as a result of water deficit. The detrimental impacts on physiological and morphological attributes reflected a considerable reduction in grain yield and all contributed traits. However, the soil- and foliar-applied zinc sulfate or/and iron sulfate significantly enhanced all aforementioned depressed parameters which reflected markedly in enhancing yield traits under drought stress. Among the investigated treatments, the exogenous foliar applications were more effective in promoting drought tolerance particularly combined both micronutrients which can be employed in reducing the losses caused by drought stress in wheat-growing regions.