Dark reactions in the flowering ofLemna perpusilla 6746

Summary

This study concerns the effects of red and far-red light on flowering in the short day plantLemna perpusilla 6746. The critical day length for maximum flowering was found to be 10 hours. Exposure to red light near the middle of the dark period inhibited flowering, and the time of maximum sensitivity to red light occurred 9 hours after the beginning of dark periods of either 14 or 17 hours. The inhibition by red light was not reversible by far-red light, which also inhibited flowering, especially when given early in the dark period. Flowering inhibited by exposure to far-red light at the beginning of the dark period could be restored by subsequent exposure to red light. It appears that two photoperiodic partial processes in some plants may be controlled by the red, far-red reversible pigment system.