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Drought stress affects plant growth and development by altering physiological and biochemical processes resulting in reduced crop productivity. Zinc (Zn) is an essential micronutrient that plays fundamental roles in crop resistance against the drought stress by regulating various physiological and molecular mechanisms. Under drought stress, Zn application improves seed germination, plant water relations, cell membrane stability, osmolyte accumulation, stomatal regulation, water use efficiency and photosynthesis, thus resulting in significantly better plant performance. Moreover, Zn interacts with plant hormones, increases the expression of stress proteins and stimulates the antioxidant enzymes for counteracting drought effects. To better appraise the potential benefits arising from optimum Zn nutrition, in the present review we discuss the role of Zn in plants under drought stress. Our aim is to provide a complete, updated picture in order to orientate future research directions on this topic.

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Zinc (Zn) deficiency caused by inadequate dietary intake is a global nutritional problem, particularly in developing countries. Therefore, zinc biofortification of wheat and other cereal crops is being urgently addressed and highly prioritized as a research topic. A field study was planned to evaluate the influence of zinc application on grain yield, grain zinc content, and grain phytic acid concentrations of wheat cultivars, and the relationships between these parameters. Three wheat cultivars, C1 = Faisalabad-2008, C2 = Punjab-2011, and C3 = Millet-2011 were tested with five different methods of zinc application: T1 = control, T2 = seed priming, T3 = soil application, T4 = foliar application, and T5 = soil + foliar application. It was found that grain yield and grain zinc were positively correlated, whereas, grain phytic acid and grain zinc were significantly negatively correlated. Results also revealed that T5, T3, and T4 considerably increased grain yield; however, T2 only slightly enhanced grain yield. Grain zinc concentration increased from 33.1 and 33.7 mg kg−1 in T1 to 62.3 and 63.1 mg kg−1 in T5 in 2013–2014 and 2014–2015, respectively. In particular, T5 markedly decreased grain phytic acid content; however, maximum concentration was recorded in T1. Moreover, all the tested cultivars exhibited considerable variation in grain yield, grain zinc, and grain phytic acid content. In conclusion, T5 was found to be most suitable for both optimum grain yield and grain biofortification of wheat.