Stomata: custodians of leaf gaseous exchange

Stomata are a key feature of all higher terrestrial plants and are found in different numbers and patterns on the aerial surfaces of most green tissues. The surrounding guard cells modulate the size of the stomatal pore in response to environmental conditions and internal cues in a manner that optimizes the rate of CO₂ uptake for photosynthesis while minimizing water loss. Stomatal conductance (gs) is a measure of the capacity for gas exchange between the inside of the leaf and the atmosphere, and is dependent on stomatal density (SD), size (SS), and aperture. Changes in gs regulate photosynthesis (A) and water loss, with significant implications for plant performance and crop yield. Stomata are therefore a major target for crop improvement via enhanced photosynthesis, optimal biochemical performance, and improved water use efficiency. This topic was part of the SEB centenary meeting in Edinburgh 2023, and forms the basis for this Special Issue. The meeting brought together researchers exploring a range of approaches to monitor, manipulate, and understand stomatal responses to a number of biotic and abiotic challenges with the ambition to develop plants that are more productive and more resilient in the face of climate change.