Abstract
Maize (Zea mays L.) is an important cereal crop globally and regarded sensitive to water stress. Exogenous application of micronutrients such as zinc (Zn) and silicon (Si) significantly improves abiotic stress tolerance of crop plants. Therefore, the current study assessed the effects of combined Zn and Si application on the growth, gas exchange, and yield-related traits of maize plants subjected to water stress. The plants were grown under either well-watered (75% water holding capacity - WW) or water stress (50% water holding capacity - DS) conditions. Three soil-applied Zn levels [i.e., 0 (Zn0), 10 (Zn10) and 20 (Zn20) mg kg−1] and two soil-applied Si levels [i.e., 0 (Si0) and 100 (Si100) mg kg−1] were included in the study. Increased leaf area, root length, number of roots per plant, chlorophyll contents, stomatal conductance, transpiration and photosynthetic rates, plant height, cob length, number of grains per cob, 100-grain weight, and grain and biological yields were recorded for the plants grown under WW conditions supplemented with Zn10 and Si100. Conversely, the plants grown without Zn and Si supplementation under DS displayed the lowest values for these traits. The supplementation of Zn10 and Si100 considerably enhanced growth, gas exchange, and yield-related traits of maize plants cultivated under DS compared to their no application. In conclusion, soil application of Zn10 and Si100 improved growth, gas exchange, and yield-related characteristics of maize plants under DS; therefore, maize should be supplemented with these nutrients to improve yield and economic returns.