Thermoperiodic effect on flowering and endogenous hormonal status in Dendrobium (Orchidaceae).
Two year-old cloned plants of Dendrobium Second Love were submitted to 25 degrees C (light) and 10 degrees C (dark) under a 12h photoperiod (60 micromol m(-1)s(-1)) for 30 days. The endogenous levels of IAA, ABA, and the cytokinins Z, [9R]Z, iP, and [9R]iP were measured 15, 22, and 30 days after the start of the thermoperiodic treatment in lateral buds and leaves. The endogenous levels of IAA and cytokinins, especially the zeatin-derived forms, increased significantly in buds after 15 days of treatment. On the other hand, the amount of ABA decreased progressively and significantly throughout the treatment. The treatment conspicuously accelerated flower-bud development. The found correlation suggests that hormones are involved in the signal transduction pathway of thermoperiodic flowering control.
Campos
Kátia Oliveira
KO
Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo CEP 05422-970, Brazil.
Kerbauy
Gilberto Barbante
GB
D031667:Dendrobium / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D035264:Flowers / Q000502:physiology*; D010507:Periodicity; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000502:physiology; D013696:Temperature
D010937:Plant Growth Regulators