Reproductive success in cereals is determined primarily by grain setting and grain filling. The kernel abortion in maize during pre-anthesis drought has been widely studied, but the reasons behind this abortion are still largely unknown. The present study investigated the impact of drought stress (control and drought) around pollination and foliar sprays of potassium (K; 0, 1, 2 and 5% K2SO4) on leaf K concentrations and yield determinants of maize under greenhouse and field conditions. Results of both experiments revealed that drought stress before pollination strongly reduced the cob fresh weights, number of grains per cob and hence grain yields. While cob length, cob diameter and grain weights were only slightly affected by drought. Potassium concentrations in cob leaves of drought stressed plants were slightly below the critical threshold values. Foliar spray of 2 and 5% K significantly increased the leaf K concentration, number of grains per cob and grain yield in drought treatments of both experiments. Foliar application of K had little or no significant effect on growth and yield determinants of control plants. It is concluded that potassium deficiency could be one factor associated with poor kernel setting under drought stress. Foliar application of 2 and 5% K2SO4 before silking can significantly improve grain number and grain yield in droughtstressed maize.

In recent decades, global climate change and heavy metal stress have severely affected plant growth and biomass, which has led to a serious threat to food safety and human health. Anthropogenic activities, the rapid pace of urbanization, and the use of modern agricultural technologies have further aggravated environmental conditions, resulting in limited crop growth and productivity. This review highlights the various adaptive transcriptomic responses of plants to tolerate detrimental environmental conditions, such as drought, salinity, and heavy metal contamination. These stresses hinder plant growth and development by disrupting their physiological and biochemical processes by inducing oxidative stress, nutritional imbalance, and osmotic disturbance, and by deteriorating their photosynthetic machinery. Plants have developed different strategies to safeguard themselves against the toxic effects of these environmental stresses. They stimulate their secondary messenger to activate cell signaling, and they trigger other numerous transcriptomic responses associated with plant defense mechanisms. Therefore, the recent advances in biological sciences, such as transcriptomics, metabolomics, and proteomics, have assisted our understanding of the stress-tolerant strategies adopted by plants, which could be further utilized to breed tolerant species. This review summarizes the stress-tolerant strategies of crops by covering the role of transcriptional factors in plants.