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Stimulation of shoot elongation in Salix pentandra by gibberellin A 9 ; activity appears to be dependent upon hydroxylation to GA l via GA 20
Author(s) -
Junttila Olavi,
Jensen Einar,
Pearce David W.,
Pharis Richard P.
Publication year - 1992
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1992.tb08773.x
Subject(s) - shoot , elongation , gibberellin , photoperiodism , metabolite , botany , biology , horticulture , hydroxylation , biochemistry , enzyme , materials science , metallurgy , ultimate tensile strength
Cessation of shoot elongation in seedlings of Salix pentandra L. is induced by short photoperiod. Gibbereliin A 9 (GA 9 ) applied either to the apical bud or injected into a mature leaf, induced shoot elongation under a short photoperiod of 12 h, and GA 9 could completely substitute for a transfer to a long photoperiod. When [ 3 H]GA 9 or [ 2 H 2 ]GA 9 was injected into a leaf, no [ 3 H]GA 9 was detected in the elongating apex and only traces of [ 3 H]GA 9 were found in the shoot above the treated leaf. By the use of gas chromatography‐mass spectrometry (GC‐MS), [ 2 H 2 ]GA 20 was identified as the main metabolite of [ 2 H 2 ]GA 9 in both the shoot and the treated leaf. In addition, [ 2 H 2 ]GA 1 and [ 2 H 2 ]GA 29 were also identified as metabolites of [ 2 H 2 ]GA 9 . These results are consistent with the hypothesis that exogenous GA, promotes shoot elongation in Salix through its metabolism to GA 20 and GA,.