Inhibitory role of gibberellins in theobroxide-induced flowering of Pharbitis nil.
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.
Gao
Xiquan
X
Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Kong
Fanjiang
F
Wang
Fang
F
Matsuura
Hideyuki
H
Yoshihara
Teruhiko
T
D018548:Cotyledon / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D003510:Cyclohexanes / Q000494:pharmacology*; D004852:Epoxy Compounds / Q000494:pharmacology*; D035264:Flowers / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D005875:Gibberellins / Q000502:physiology*; D049915:Ipomoea nil / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D017440:Photoperiod; D010940:Plant Proteins / Q000502:physiology; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
D003510:Cyclohexanes; D004852:Epoxy Compounds; D005875:Gibberellins; D010940:Plant Proteins; C496818:theobroxide