rates of starch synthesis and CO2 assimilation and between the
rates of starch synthesis and cumulative plant growth. These observations
suggest that leaf starch is not only important as a transient
reserve whose metabolism supports heterotrophic growth in the
dark but also as an essential end-product in triose-P utilization. An
indirect result of conversion of triose-P into starch is the recycling of
Pi for ATP synthesis and, thereby, potentially minimizing feedback
regulation of photosynthesis. In this study, we present evidence to
support this hypothesis on the relationship between leaf starch,
photosynthetic capacity, and plant growth in Arabidopsis and rice.
Moreover, our results show that contrary to prevailing views, there
are conditions where photosynthesis is not optimal even under current
CO2 levels due to feedback regulation, and that leaf starch can
be exploited to enhance photosynthesis capacity and plant growth.