Development, Anatomy, and Integrated Function of Grass Leaf Veins and Graminoid Stomata.

Grasses (Poaceae) dominate many natural and agricultural ecosystems. Grasses form longitudinal leaves with parallel venation and highly specialized, graminoid stomatal complexes. Theoretical concepts and experimental studies highlight that these anatomical features contribute to physiologically innovative properties, including enhanced capacity and dynamics of water transport and gas exchange. The genetic and molecular regulators underlying vein and epidermal patterning in grasses continue to be elucidated in model species, though integration of these processes is lacking. This review summarizes our current understanding of leaf vein and leaf epidermal development, describes the morphological and physiological characteristics of grass leaves, and highlights those related to water transport pathways and gas exchange. We conclude that an integrative anatomical and physiological framework linking water transport supply and demand must be considered for developmental research and novel crop design. This will enable an understanding of the causes and consequences of anatomical patterns of diverse grass leaves and their translational potential for agriculture in a changing climate.