Optimal Photoperiod Treatment for Flowering of Bougainvillea xbuttiana 'Afterglow'

摘要

Bougainvillea Xbuttiana cultivars are mostly considered qualitative short-day plants that flower more readily and profusely under short day lengths. The cultivar 'Afterglow' was tested in two experiments to confirm that it is a qualitative short-day plant, and to discover the optimal photoperiod under which flowering is most profuse. Seventy plants were subjected to a range of photoperiods from 8-14 hours in 1-hour increments, to establish an optimal photoperiod for the induction of flowering in theabsence of other environmental factors, namely water stress, physical wounding, or high nutrient availability. Experiment 1 confirmed that 'Afterglow' is a short-day plant, producing the most flowers between 8 and 11 hours of daylight. Plants under long-day or short-day with night interruption provided by a single white LED bulb producing 240 umolm~(-2)s~(-1) of photosynthetic photon flux did not produce flowers. Experiment 2 showed that plants grown under an 8-hour photoperiod produced the largest number of flowers.