Increasing leaf vein density in rice results in an enhanced rate of photosynthesis

Increased leaf vein density is considered to be a key early step in the evolution of C4 photosynthesis.  Feldman et al. analyzed five mutants with high vein densities in the C3 crop rice to determine if photosynthetic assimilation was improved.  The mutants all had higher photosynthetic rates under saturating light, while not showing any characteristics of C4 photosynthesis.  This potentially arose from an increase in the activation state of Rubisco, itself conferred by augmented hydraulic capacity.  It is also possible that enhanced transport of photoassimilates plays in role in boosting photosynthesis in these mutants. (Summary by Mike Page) Front. Plant Sci. 10.3389/fpls.2017.01883