Abscisic acid affects floral initiation in Polianthes tuberosa

Application of 5 or 25 μg abscisic acid (ABA) per plant to the upper part of corms of Polianthes tuberosa L. (cv. Double) at the vegetative stage inhibited floral initiation and plant height, especially when ABA at 25 μg per plant was applied. The contents of endogenous free ABA in corms decreased significantly at the floral initiation stage, and remained at a low level at flower development stage as compared with the vegetative stage. However, no significant changes in bound ABA levels were observed at three different growth stages of corm development. These results suggest that the dramatic reduction in the free ABA content in corm tissues are correlated with floral initiation and flower development in P. tuberosa.