© 1991 Heron Publishing—Victoria, Canada
A source–sink framework for coupling water, carbon, and nutrient dynamics of vegetation
R. J. Luxmoore
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA /
Summary
Feedbacks between photosynthesis and growth and the influence on these relationships of environmental factors are reviewed.
The evidence indicates a strong dependence of photosynthesis on photosynthate utilization. It also indicates that growth is
more sensitive than photosynthesis to water and mineral nutrient stress. As a consequence, many relationships between photosynthesis
and external driving variables are confounded by internal feedback effects that reflect the influence of external factors
on growth. A source–sink framework for modeling carbon dynamics with coupled water and nutrient interactions in soil–plant
systems is outlined. Simulations based on these concepts suggest that sink feedback regulation of photosynthesis at various
times in diurnal, wetting–drying, and annual cycles is probably a common occurrence in soil–plant systems.
