The lack of correlation between photosynthesis and growth under “sink-limited” conditions (e.g. limited by nutrients, temperature and/or water stress) is a long-standing puzzle in plant ecophysiology. This gap in our understanding severely compromises the capacity of models to project vegetation responses to global change.
To address this puzzle, we applied data assimilation of a simple carbon balance model to an experiment where sink strength was manipulated by restricting root volume. Our analysis framework allowed us to infer that, in addition to a feedback on photosynthetic rates, the reduction in growth was affected by other carbon balance processes (e.g. enhanced respiration losses, modified carbon allocation, increase leaf turnover).
Paper: Mahmud, K., Medlyn, B. E., Duursma, R. A., Campany, C. and De Kauwe, M. G. (2018) Inferring the effects of sink strength on plant carbon balance processes from experimental measurements. Biogeosciences Discussions, DOI: 10.5194/bg-2018-99