Leaf hydraulic conductance is coordinated with leaf morpho-anatomical traits and nitrogen status in the genus Oryza

Abstract

Leaf hydraulic conductance (Kleaf) is a major determinant of photosynthetic rate in plants. Previous work has assessed the relationships between leaf morpho-anatomical traits and Kleaf with woody species, but there has been very little focus on cereal crops. The genus Oryza, which includes rice (Oryza sativa) and wild species (such as O. rufipogon cv. Griff), is ideal material for identifying leaf features associated with Kleaf and gas exchange. Leaf morpho-anatomical traits, Kleaf, leaf N content per leaf area, and CO2 diffusion efficiency were investigated in 11 Oryza cultivars. Kleaf was positively correlated with leaf thickness and related traits, and therefore positively correlated with leaf mass per area and leaf N content per leaf area, and negatively with inter-veinal distance. Kleaf was also positively correlated with leaf area and its related traits, and therefore negatively correlated with the proportion of minor vein length per area. In addition, coordination between Kleaf and CO2 diffusion conductance in leaves was observed. We conclude that leaf morpho-anatomical traits and N content per leaf area strongly influence Kleaf. Our results suggest that more detailed anatomical and structural studies are needed to elucidate the impacts of leaf feature traits on Kleaf and gas exchange in grasses.