Differential effects of the embryonic axis on chlorophyll production and photosynthesis of mustard cotyledons.

Mustard cotyledons detached from the dry seed or at intervals during five days dark germination produced consistently more chlorophyll but a lower photosynthetic rate when maintained in the dark on moist filter paper for 24 hr before exposure to light than cotyledons which were attached to the seedling axis during this time.The results suggest that the embryonic axis exerts a differential effect on the developing photosynthetic system, competing for material involved in chlorophyll formation and at the same time stimulating the development of other photosynthetic components.