Flower Induction by Daily 17-h Culture on Nitrogen-Free Medium in Lemna paucicostata 6746

Daylength-independent flowering in Lemna paucicostata 6746,a short-day plant, was induced by daily treatment with nitrogendeficiency for 17 hours, which inhibited nitrate reductase activity.The endogenous nitrogen level in plants treated daily with 17-hnitrogen deficiency was much higher than in plants culturedon medium containing 50–200 and 1,000µM nitratefor 10 and 14 days, respectively, which were induced to flower.These results suggest that suppression of nitrogen metabolismfor more than a certain number of hours can induce floweringeven in plants with a high nitrogen level. (Received January 16, 1987; Accepted August 28, 1987)