Recent insights into air space formation in plant shoots.

An adequate supply of oxygen and carbon dioxide is essential for plant survival. Although plant cell walls are somewhat porous, their hydrated nature hampers gas diffusion. Furthermore, the cuticular wax coating the epidermal layer of aerial tissues strongly inhibits gas exchange. Because plants lack specialized systems that bind and transport gases, gases must be directly delivered to the target cells. This necessitates the establishment of effective gas transport pathways connecting stomata to the target cells. However, our understanding of this process remains fragmented. Recent studies have shed light on the mechanisms underlying air space formation in various model and non-model plant species. This review aims to consolidate these findings, to provide a comprehensive overview of our current understanding of air space formation, and to outline potential avenues for future research that will address remaining gaps in knowledge.