Photoperiodic Control of Flowering of Salvia leucantha

Abstract

Abstract Plants of Salvia leucantha were subjected to 8, 10, 12, or 14 hr of light under controlled environmental conditions. Salvia leucantha is a short-day plant with a critical photoperiod of 12 hr for macrobud development, but 10 hr for subsequent flower development. About 14 photoperiodic cycles are necessary for flower initiation, but at least 42 cycles are required for normal anthesis and raceme elongation. Apices that had initiated under < 6 weeks of short days failed to develop when placed under long days. Flower initiation did not occur when night break lighting of 1.3 μmol·s−1·m−2 was provided by incandescent lamps.