Leaf anatomy mediates coordination of leaf hydraulic conductance and mesophyll conductance to CO 2 in Oryza

Summary Leaf hydraulic conductance ( K leaf ) and mesophyll conductance ( g m ) both represent major constraints to photosynthetic rate ( A ), and previous studies have suggested that K leaf and g m is correlated in leaves. However, there is scarce empirical information about their correlation. In this study, K leaf , leaf hydraulic conductance inside xylem ( K x ), leaf hydraulic conductance outside xylem ( K ox ), A , stomatal conductance ( g s ), g m , and anatomical and structural leaf traits in 11 Oryza genotypes were investigated to elucidate the correlation of H 2 O and CO 2 diffusion inside leaves. All of the leaf functional and anatomical traits varied significantly among genotypes. K leaf was not correlated with the maximum theoretical stomatal conductance calculated from stomatal dimensions ( g smax ), and neither g s nor g smax were correlated with K x . Moreover, K ox was linearly correlated with g m and both were closely related to mesophyll structural traits. These results suggest that K leaf and g m are related to leaf anatomical and structural features, which may explain the mechanism for correlation between g m and K leaf .