EFFECTS OF PHOTOPERIOD AND KIND OF SUPPLEMENTAL LIGHT ON GROWTH, FLOWERING, AND STEM FASCIATION OF CELOSIA

Abstract

P iringer , A. A., and H. A. B orthwick . (U.S.D.A., Beltsville, Md.) Effects of photoperiod and kind of supplemental light on growth, flowering and stem fasciation of Celosia. Amer. Jour. Bot. 48(7): 588–592. Illus. 1961.—Four cultivars of Celosia argentea L. var. cristata were grown on photoperiods ranging from 8 hr to continuous light. Supplemental low‐intensity incandescent light was used to extend 8 hr of natural light and provide the given photoperiod. In all cultivars, short main stems occurred on photoperiods of 12 or fewer hours and long main stems, due to more nodes, on photoperiods of 16 or more hours. Flowering was a nonobligate short‐day response in all cultivars. Plants of certain cultivars tended to have shorter stems and flower later when 8 hr of fluorescent instead of incandescent light was used to provide the 16‐hr photoperiod. In 3 of the cultivars studied, photoperiods of 16 or more hours induced marked stem fasciation.