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Research article - Peer-reviewed, 1997

Long-day induced bud break in Salix pentandra is associated with transiently elevated levels of GA(1) and gradual increase in indole-3-acetic acid

Olsen, Jorunn E.; Junttila, Olavi; Moritz, Thomas


Initiation of dormancy in woody species is induced by a short photoperiod. In the early stages of dormancy development, growth can be initiated by long days. To study the possible involvement of gibberellins and indole-3-acetic acid in bud break in Salix pentandra, effects on levels of these plant hormones of transfer of seedlings in an early stage of dormancy to a growth-inductive long photoperiod was investigated. The bud break and initiation of growth correlated with a rapid transient increase in GA, in defined zones of shoot tips to levels twice of that in continuously elongating long day-grown control seedlings, followed by a rapid decrease to levels similar to in these control plants. Also, the contents of GA(53), GA(19), GA(201) GA(8) increased upon transfer from short to long days. Levels of indole-3-acetic acid showed a gradual decline under short days, and increased gradually upon transfer to long days up to a level of continuously elongating plants. The present data suggest an interaction between gibberellin and indole-3-acetic acid in the photoperiodic control of dormancy development and bud break in S. pentandra.


bud break; gibberellins; IAA; indole-3-acetic acid; photoperiod; Salix pentandra

Published in

Plant and Cell Physiology
1997, volume: 38, number: 5, pages: 536-540

Authors' information

Olsen, Jorunn E.
University of Tromso, the Arctic University of Norway (UiT)
Junttila, Olavi
University of Tromso, the Arctic University of Norway (UiT)
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology

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