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

Mesophyll CO₂ conductance (g_m) 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 g_m.  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 g_m.  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