Articles
EFFECT OF LOW TEMPERATURE ON FLOWERING AND ENDOGENOUS HORMONAL STATUS IN DENDROBIUM SCABRILINGUE L.
Article number
884_87
Pages
651 – 656
Language
English
Abstract
Four hundred mature plants were transferred to thermo-periodically controlled growth chambers with alternating (12/12 h) day/night temperature of 25/15°C vs. 30/25°C for four weeks.
The photoperiod was achieved by fluorescent lamps (60 µmolm-2s-1). Concentrations of free cytokinins (CKs), auxin (IAA), gibberellins (GAs) and abscisic acid (ABA) in buds, stem, leaves and leaf diffusates were measured at 5-7 day intervals from 1 to 43 days after beginning of the treatment.
Within 14 days of cool temperature concentrations of CKs increased significantly in stem, leaves, buds and leaf diffusates, whereas during the same time period concentrations of IAA and GAs decreased in stem and buds, but increased again between 21 and 28 days after treatment.
ABA concentrations were not significantly different between control and treatment in all plant tissues.
Histological sections of bud meristems revealed that the observed time period of high CK:IAA ratio coincided with the stage of flower induction (FI), whereas increasing concentrations of IAA and GAs occurred in parallel to the onset of flower development.
The hormonal changes during FI correspond to those obtained from FI experiments in longan, litchi and mango.
The photoperiod was achieved by fluorescent lamps (60 µmolm-2s-1). Concentrations of free cytokinins (CKs), auxin (IAA), gibberellins (GAs) and abscisic acid (ABA) in buds, stem, leaves and leaf diffusates were measured at 5-7 day intervals from 1 to 43 days after beginning of the treatment.
Within 14 days of cool temperature concentrations of CKs increased significantly in stem, leaves, buds and leaf diffusates, whereas during the same time period concentrations of IAA and GAs decreased in stem and buds, but increased again between 21 and 28 days after treatment.
ABA concentrations were not significantly different between control and treatment in all plant tissues.
Histological sections of bud meristems revealed that the observed time period of high CK:IAA ratio coincided with the stage of flower induction (FI), whereas increasing concentrations of IAA and GAs occurred in parallel to the onset of flower development.
The hormonal changes during FI correspond to those obtained from FI experiments in longan, litchi and mango.
Authors
S. Sarathum, S. Tantiviwat, M. Nanakorn, M. Hegele, J.N. Wünsche
Keywords
orchid, cool temperature, hormonal changes, flower induction, histological section, bud meristem
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