Light was not essential for the development of ribulose-1,5-diphosphate carboxylase protein or catalytic activity in the photosynthetic cotyledons of germinating castor beans (Ricinus communis). Cotyledons developing in the dark showed higher activity than those in the light. Returning cotyledons developing in the light to darkness resulted in a significant increase in ribulose-1,5-diphosphate carboxylase activity compared to cotyledons in continuous light.
