Turning over a new leaf on photosynthesis

Andreas Stillits, PhD Student, Biocomplexity Group, Niels Bohr Institute

Efforts towards understanding and potentially optimizing photosynthetic yield in plants rely on biophysical models to quantify the limitations posed by individual physiological components. In order to be assimilated, CO2 has to diffuse from the atmosphere, through the leaf tissues, and ultimately into chloroplasts in leaf cells where photoactive enzymes reside. Enzymatic activity depends on the intracellular CO2 available and hence the physiological resistances to transport can pose a major limitation.

The dominating theoretical framework treats the transport pathway as a series of one-dimensional diffusive components - each with a resistance that depends on only two components: the local geometry and diffusive properties.

In this talk, we will set out to recover such a model from a three-dimensional reaction-diffusion description. We will find that a third component is essential for the interpretation of such resistances, and that overlooking its importance has systematically biased consensus estimates of intercellular airspace resistance in leaves.