Metabolism of tritiated and deuterated gibberellin A9 in Norway spruce (Picea abies) shoots during the period of cone-bud differentiation |
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Authors: | Thomas Moritz Per Christer Odén |
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Institution: | Dept of Forest Genetics and Plant Physiology, Swedish Univ. of Agricultural Sciences, S-901 83 Umed, Sweden |
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Abstract: | A mixture of tritiated and deuterated gibberellin A9 (GA9) was injected into elongating shoots of Norway spruce Picea abies (L.) Karst.] grafts grown under environmental conditions that were either inductive (heat and drought, HD) or noninductive (cool and wet, CW) for flowering. The shoots were divided into needles and shoot stems. The metabolites were purified by high performance liquid chromatography (HPLC), detected by liquid scintillation counting of aliquots of collected fractions and identified by gas chromatography-mass spectrometry (GC-MS). Deuterated GA9 was converted to deuterated GA4 in both treatments. The major metabolite in the CW-treated material was GA51. The HD-treated material did not convert GA9 to GA51, but a cellulase-hydrolysable GA9-conjugate was formed. The same metabolites were found in the shoot stems, though in smaller amounts. The amounts of detected metabolites were higher in the HD material, caused by a higher rate of metabolism and/or smaller losses of the metabolites during sample purification. The estimated amounts of endogenous GAs show that the HD-treated material contained higher amounts of GA9 but no differences in the amounts of GA4 were found. |
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Keywords: | Flowering gas chromatography-mass spectrometry gibberellins metabolism Norway spruce Picea abies |
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