Nature of light requirement for the flowering of Chenopodium rubrum L. (Ecotype 60° 47' N) : II. Post-induction light period.

Seedlings of C. rubrum were irradiated with different light qualities and intensities following a single inductive dark period. Our results show that relatively low intensity white light (35-100 ft. c.) does not support flower development while high intensity white light (650-800 ft. c.) permits 100% flowering. We have shown that the low intensity light inhibiton of flower development is not due to suboptimal photosynthesis. Relatively low intensities of light rich in far-red or blue wavebands sustains optimum flower development, whereas red light is totally ineffective in this respect. Considering that the intensity dependent High Energy Reaction (HER) has its action maxima in the blue and far-red we propose that HER may be positively involved in the flower development of C. rubrum. Our study further suggests that there may be some flower inhibitory component at play in relatively low intensity white light conditions and HER may be required to counteract this flower inhibitory effect.