Dynamics and mechanisms of oscillatory photosynthesis

We classify mathematical models that can be used to describe photosynthetic oscillations using ideas from nonlinear dynamics, and discuss potential mechanisms for photosynthetic oscillations in the context of this classification. We then turn our attention to recent experiments with leaves transferred to a low CO2 atmosphere which revealed stochastic oscillations with a period of a few seconds. Rubisco is the enzyme that takes both CO2 and O2 as substrates correspondingly for photosynthetic assimilation and for photorespiration. Photosynthesis depletes CO2 and produces O2 while respiration and photorespiration work in the opposite direction, so the product of one process becomes the reactant of the other coupled process. We examine the possibility of oscillations of CO2 and O2 in the leaf in relation to photorespiration. We suggest that in the cell, oscillations with a period of a few seconds, corresponding to the time between photosynthetic CO2 fixation and photorespiratory CO2 release, underlie the dynamics of metabolism in C3 plants.