Inhibitory role of gibberellins in theobroxide-induced flowering of Pharbitis nil

• Published in: Journal of plant physiology 2006-03, Vol.163 (4), p.398-404
• Main Authors: Gao, Xiquan, Kong, Fanjiang, Wang, Fang, Matsuura, Hideyuki, Yoshihara, Teruhiko
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; Cotyledon - drug effects; Cotyledon - growth & development; Cotyledon - metabolism; Cyclohexanes - pharmacology; Epoxy Compounds - pharmacology; flowering; Flowers - drug effects; Flowers - growth & development; Flowers - metabolism; Fundamental and applied biological sciences. Psychology; Gibberellins; Gibberellins - physiology; Ipomoea nil; Ipomoea nil - anatomy & histology; Ipomoea nil - drug effects; Ipomoea nil - metabolism; Night break; Pharbitis nil; Photoperiod; physiological response; plant biochemistry; plant physiology; Plant physiology and development; Plant Proteins - physiology; plant response; seedling growth; seedlings; Seedlings - drug effects; Seedlings - growth & development; Seedlings - metabolism; Stem elongation; Theobroxide; Vegetative and sexual reproduction, floral biology, fructification
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2005.04.028

Theobroxide, a novel active compound isolated from a fungus, has been reported previously to induce potato tuberization and flower bud formation in Pharbitis nil under non-inductive long-day conditions. Up to date, the action mechanism of theobroxide on flower-bud induction of P. nil, however, is still unknown. In the present study, we observed a reduction of the stem length, along with the induction of flower buds, in theobroxide-treated and short-day-grown P. nil plants. Also, the results showed that flower bud formation was delayed markedly in P. nil seedlings with removal of cotyledons or exposure to night break. The suppression effect of night-break and cotyledon-removal, however, was abolished completely by spraying theobroxide. Endogenous gibberellin 1/3 contents in P. nil plants treated with theobroxide or grown under short-day conditions were relatively lower, suggesting that gibberellins probably are negatively involved in theobroxide- and short-day-induced flower-bud formation of P. nil.