Opinion: Prospects for improving photosynthesis by altering leaf anatomy

Engineering higher photosynthetic efficiency for greater crop yields has gained significant attention among plant biologists and breeders. To achieve this goal, manipulation of metabolic targets and canopy architectural features has been heavily emphasized. Given the substantial variations in leaf anatomical features among and within plant species, there is large potential to engineer leaf anatomy for improved photosynthetic efficiency. Here we review how different leaf anatomical features influence internal light distribution, delivery of CO2 to Rubisco and water relations, and accordingly recommend features to engineer for increased leaf photosynthesis under different environments. More research is needed on (a) elucidating the genetic mechanisms controlling leaf anatomy, and (b) the development of a three dimensional biochemical and biophysical model of leaf photosynthesis, which can help pinpoint anatomical features required to gain a higher photosynthesis.

► Variation in leaf anatomical features can cause changes in photosynthetic efficiency.
► Chlorophyll distribution and chloroplast surface area facing intercellular space can be modified to improve photosynthesis.
► Cell wall and bundle-sheath extensions can be modified to influence photosynthetic efficiency.
► A systems model of leaf photosynthesis can help define ideal leaf anatomy under different conditions.
► A leaf model needs to include biochemical, biophysical and anatomical aspects to guide engineering.