Cell wall properties in Oryza sativa influence mesophyll carbon dioxide conductance (New Phytol) $

Mesophyll CO2 conductance (gm) is an important factor in determining the concentration of CO2 at the site of fixation in the chloroplast stroma, and as such is crucial for determining photosynthetic capacity.  The mesophyll cell wall provides a major site of resistance to CO2 diffusion into the stroma from the intercellular air space.  Ellsworth et al investigated the effect of modulating cell wall properties on gm.  The authors studied cslf6 mutants of rice, which do not have detectable mixed-linkage glucans (MLGs) in their cell walls.  While these mutants had thinner cell walls, their effective porosity was reduced, leading to a marked reduction in gm.  This was likely caused by modification of both porosity and tortuosity of cslf6 cell walls.  This study emphasises the important role cell wall composition plays in determining CO2 diffusion and, consequently, photosynthetic capacity.  (Summary by Mike Page) New Phytol 10.1111/nph.15173