Stomata

Abstract

Stomata are cellular pores on the aerial surface of plants. They open to allow the uptake of carbon dioxide and close to limit water loss, and thus are essential for plant growth and homeostasis. Stomata, which are common to almost all land plants, represent a critical evolutionary innovation of early land plants. A stoma is formed by a pair of guard cells, which are the final products of a specialised cell lineage. Mature guard cells mediate stomatal opening and closing by regulating the fluxes of ions, and hence water, in and out of the cells. To maximise fitness in the ever‐changing environments, both the development and movement of the stomatal guard cells are highly responsive to diverse environmental signals. These stomatal responses will likely play a key role in plant adaptation and agricultural production in the face of global climate change. Key Concepts Stomata are small adjustable pores on the leave surface that enable gas exchange. Open stomata allow the uptake of carbon dioxide for photosynthesis, while closed stomata prevent excessive loss of water. During evolution, stomata enabled plants to survive the drier environments on land. The development of stomata involves several cell fate transition steps and is driven by cell‐type‐specific master transcription factors. Stomatal movements are controlled by a pair of guard cells, which change their cell volume through ion‐driven uptake and release of water. Environmental signals regulate both the development and movement of guard cells, allowing plants to best adapt to their surroundings. Stomata are likely to be important in the adaption of plants to global warming.