Phytochrome-mediated effects of near-ultraviolet radiation in the induction of flowering in etiolated Lemna paucicostata T-101, a short-day plant.

Induction of flowering of etiolated Lemna paucicostata Hegelm. T-101, a short-day plant, was inhibited by far-red (FR) or blue light (BL) applied at the beginning of a 72-h inductive dark period which was followed by two short days. In either case the inhibition was reversed by a subsequent exposure of the plants to near-ultraviolet radiation (NUV), with a peak of effectiveness near 380 nm. Inhibition by BL or FR and its reversion by NUV are repeatable, i.e., NUV is acting in these photoresponses like red light although with much lower effectiveness. Thus, it is considered that NUV acts through phytochrome and no specific BL and NUV photoreceptor is involved in photocontrol of floral induction on this plant.