Abstract
Isolated rooted sweet potato leaves were used to study the effect of carbohydrate use and storage on photosynthesis. Tubering of the roots was controlled (1) by varying the moisture around the roots, (2) by varying the root temperature, or (3) by treating the leaves with growth regulators. When tubering was greatest the total dry matter formed per unit area of leaf was also greatest. Benzyl adenine applied to the lamina increased the proportion of total dry matter in the tubers. The experiments show that increasing tuber growth increases net assimilation rate, supporting the view that rate of photosynthesis depends on the capacity of sinks to accept photosynthate.