Abiotic stresses are one of the major constraints to crop production and food security worldwide. The situation has aggravated due to the drastic and rapid changes in global climate. Heat and drought stress are undoubtedly the two most important stresses having huge impact on growth and productivity of the crops. It is very important to understand the physiological, biochemical and ecological interventions related to these stresses for better management. A wide range of plant responses to these stresses could be generalized into morphological, physiological and biochemical responses. Interestingly, this review provides a detailed account of plant responses to heat and drought stresses with special focus on highlighting the commonalities and differences. Crop growth and yields are negatively affected by sub-optimal water supply and abnormal temperatures due to physical damages, physiological disruptions and biochemical changes. Both these stresses have multi-lateral impacts and therefore, complex in mechanistic action. A better understanding of plant responses to these stresses has pragmatic implication for remedies and management. A comprehensive account of conventional as well as modern approaches to deal with heat and drought stresses have also been presented here. A side-by-side critical discussion on salient responses and management strategies for these two important abiotic stresses provides a unique insight into the phenomena. A holistic approach taking into account the different management options to deal with heat and drought stress simultaneously could be a win-win approach in future.

Consequences of drought stress in crop production systems are perhaps more deleterious than other abiotic stresses under changing climatic scenario. Regulations in physio-biochemical responses under drought stress are crafted in to agronomic traits by the plants that can be used as markers for drought stress tolerance from selection and breeding point of view. Present study was conducted to appraise the performance of three different maize hybrids i.e., Dong Dan 80, Wan Dan 13 and Run Nong 35 under well watered, low, moderate and severe drought conditions maintained at 100, 80, 60 and 40% field capacities, respectively. Compared with well-watered, drought stress exhilarated oxidative stress in terms of reactive oxygen species (ROS) production which led to reduced growth and yield formation in all maize hybrids; nevertheless negative effects were more prominent in Run Nong 35. Drought-induced osmolyte accumulation and strong enzymatic and non-enzymatic defense system prevented severe damages in Dong Dan 80. Furthermore, in most of the cases correlations of ROS, omolytes and anti-oxidant defense system were found negative with shoot dry weight (SDW), grain yield (GY) and biological yield (BY) under drought conditions. Overall performance of all maize hybrids under drought stress was recorded as: Dong Dan 80 > Wan Dan 13 > Run Nong 35 with 6.39, 7.35 and 16.55% yield reductions. Consequently, these biochemical traits and differential physiological responses might be helpful to develop drought tolerance genotypes that can withstand against water-deficit conditions with minimum yield losses.

Little is known of glyphosate-induced hormesis in weeds and how this might influence weed management. To test the hormetic effect of low doses of glyphosate on broad-leaved weeds, two experiments were conducted, in the laboratory and the screenhouse. The hormetic effects of glyphosate solution in growth media (0, 65, 130, 250, and 500 g acid equivalent (a.e) ha⁻¹) and foliar spray (0, 4, 8, 16, 32, and 64 g a.e. ha⁻¹) were tested on four broad-leaved weeds (Coronopus didymus, Chenopodium album, Rumex dentatus, and Lathyrus aphaca). Glyphosate solution in the range 65–250 g a.e. ha⁻¹ stimulated the germination and seedling growth of all tested weeds. However, at 500 g a.e. ha⁻¹ inhibition of germination and growth was observed. Foliarly applied glyphosate in the range 4–32 g a.e. ha⁻¹ increased root and shoot length, dry biomass, and seed production ability of all four weeds species; however, the stimulatory response was species dependent. These results indicate that glyphosate hormesis could play a significant role in altering crop/weed competition and might influence weed management.