Effect of ultraviolet-light interruption on flowering inPharbitis seedlings

Seedlings ofPharbitis nil, strain Violet, were exposed to ultraviolet (UV, 254 nm) light at various times of a 16-hr dark period for 60, 90, and 120 sec. When UV light was given at the 6th hr of the dark period, flowering was most inhibited irrespective of UV dosages. The inhibition pattern of flowering caused by UV light was similar to that caused by red light. Contribution No. 101 from the Department of Biology, Miyazaki University.