Cell wall thickness has phylogenetically consistent effects on the photosynthetic nitrogen‐use efficiency of terrestrial plants
Wei Xue, Dandan Liu, Tiina Tosens, Dongliang Xiong, Marc Carriquí, You‐Cai Xiong, Jonghan Ko
Abstract
Abstract Leaf photosynthetic nitrogen‐use efficiency (PNUE) diversified significantly among C 3 species. To date, the morpho‐physiological mechanisms and interrelationships shaping PNUE on an evolutionary time scale remain unclear. In this study, we assembled a comprehensive matrix of leaf morpho‐anatomical and physiological traits for 679 C 3 species, ranging from bryophytes to angiosperms, to comprehend the complexity of interrelationships underpinning PNUE variations. We discovered that leaf mass per area (LMA), mesophyll cell wall thickness (T cwm ), Rubisco N allocation fraction (P R ), and mesophyll conductance (g m ) together explained 83% of PNUE variations, with P R and g m accounting for 65% of those variations. However, the P R effects were species‐dependent on g m , meaning the contribution of P R on PNUE was substantially significant in high‐g m species compared to low‐g m species. Standard major axis (SMA) and path analyses revealed a weak correlation between PNUE and LMA ( r 2 = 0.1), while the SMA correlation for PNUE–T cwm was robust ( r 2 = 0.61). P R was inversely related to T cwm , paralleling the relationship between g m and T cwm , resulting in the internal CO 2 drawdown being only weakly proportional to T cwm . The coordination of P R and g m in relation to T cwm constrains PNUE during the course of evolution.