Induction of Flowering in Long Day Plants by Applied Indoleacetic Acid

Abstract
Indoleacetic acid (IAA) has been used to induce flowering in Hyoscyamus niger and Silene armeria, long day species. When these species are given daily cycles of 8 hrs. of high intensity light in the greenhouse followed by 16 hrs. of supplementary incandescent light of such low intensity that controls remain vegetative, application of IAA causes as much as 100% flowering. IAA was applied daily as a water solution containing a detergent. The effective concentration varies from 3 to 30 mg/L. apparently depending upon the physiological state of the plant at time of treatment.