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Climate change is altering our environment, subjecting multiple agroecosystems worldwide to an increased frequency and intensity of abiotic stress conditions such as heat, drought, flooding, salinity, cold and/or their potential combinations. These stresses impact plant growth, yield and survival, causing losses of billions of dollars to agricultural productivity, and in extreme cases they lead to famine, migration and even wars. As the rate of change in our environment has dramatically accelerated in recent years, more research is urgently needed to discover and develop new ways and tools to increase the resilience of crops to different stress conditions. In this theme issue, new studies addressing the molecular, metabolic, and physiological responses of crops and other plants to abiotic stress challenges are discussed, as well as the potential to exploit these mechanisms in biotechnological applications aimed at preserving and/or increasing crop yield under our changing climate conditions. This article is part of the theme issue ‘Crops under stress: can we mitigate the impacts of climate change on agriculture and launch the ‘Resilience Revolution’?’ 

Differential transpiration is a newly discovered acclimation strategy of annual plants that mitigates the negative impacts of combined water deficit (WD) and heat stress (HS) on plant reproduction. Under conditions of WD + HS, transpiration of vegetative tissues is suppressed in plants such as soybean and tomato, while transpiration of reproductive tissues is not (termed ‘Differential Transpiration’; DT). This newly identified acclimation process enables the cooling of reproductive organs under conditions of WD + HS, limiting HS‐induced damage to plant reproduction. However, the thresholds at which DT remains active and effectively cools reproductive tissues, as well as the developmental stages at which it is activated in soybean, remain unknown. Here, we report that DT occurs at most nodes (leaf developmental stages) of soybean plants subjected to WD + HS, and that it can function under extreme conditions of WD + HS (i.e.,18% of field water capacity and 42°C combined). Our findings reveal that DT is an effective acclimation strategy that protects reproductive processes from extreme conditions of WD + HS at almost all developmental stages. In addition, our findings suggest that, under field conditions, DT could also be active in plants subjected to low or mild levels of WD during a heat wave. 

An increase in the frequency and intensity of heat waves, floods, droughts and other environmental stresses, resulting from climate change, is threatening agricultural food production worldwide. Heat waves are especially problematic to grain yields, as the reproductive processes of almost all our main grain crops are highly sensitive to heat. At times, heat waves can occur together with drought, high ozone levels, pathogen infection and/or waterlogging stress that suppress the overall process of plant cooling by transpiration. We recently reported that under conditions of heat and water-deficit stress combination, the stomata on sepals and pods of soybean (Glycine max) remain open, while the stomata on leaves close. This process, termed ‘differential transpiration’, enabled the cooling of reproductive organs, while leaf temperature increased owing to suppressed transpiration. In this review article, we focus on the impacts on crops of heat waves occurring in isolation and of heat waves combined with drought or waterlogging stress, address the main processes impacted in plants by these stresses and discuss ways to mitigate the negative effects of isolated heat waves and of heat waves that occur together with other stresses (i.e. stress combination), on crops, with a focus on the process of differential transpiration. This article is part of the theme issue ‘Crops under stress: can we mitigate the impacts of climate change on agriculture and launch the ‘Resilience Revolution’?’. 

Nitric oxide (NO) is a key regulator of plant development, growth, and responses to the environment. Together with hydrogen peroxide (H₂O₂), NO modifies the structure and function of proteins, controlling redox signaling. Although NO has been studied extensively at the cellular and subcellular levels, very little is known about changes in NO content at the whole‐plant level.Here, we report on the development of an aboveground whole‐plant live imaging method for NO. Using mutants with altered NO levels, as well as an NO donor/scavenger, we demonstrate the specificity of the detection method for NO.Arabidopsis thalianaplants were found to produce a basal level of NO under control conditions. NO levels accumulated enzymatically in plants following heat stress applied to the entire plant, as well as in a systemic manner following different locally applied stimuli. Similar or opposing accumulation patterns were also found for NO and H₂O₂during the response of plants to different stimuli.Our findings reveal that NO accumulates during the systemic response of plants to a local stimulus. In addition, they shed new light on the intricate relationships between NO and H₂O₂. The new method reported opens the way for multiple future studies of NO's role in plant biology. 

Two plants connected via a Cuscuta bridge exchange rapid systemic calcium, electric, and reactive oxygen species signals, suggesting that Cuscuta may have beneficial effects to host plants.