Putrescine metabolism in excised cotyledons of Pinus radiata cultured in vitro

Authors

  • Prakash P. Kumar,

    Corresponding author
    1. Plant Physiology Research Group, Dept of Biological Sciences, Univ. of Calgary, Calgary, Alberta, Canada T2N IN4.
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  • Trevor A. Thorpe

    Corresponding author
    1. Plant Physiology Research Group, Dept of Biological Sciences, Univ. of Calgary, Calgary, Alberta, Canada T2N IN4.
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P. P. Kumar and T. A. Thorpe (corresponding author)

Abstract

The metabolism of 14C-putrescine and the changes in the endogenous concentrations of putrescine, spermidine and spermine were studied when cotyledons of Pinus radiata D. Don were cultured under shoot-forming (SF, + N6-benzyladenine) and non-shoot-forming (NSF, - N6-benzyladenine) conditions. Differences in the total uptake of 14C-putrescine during a 2 h pulse feeding were not significant between the SF and NSF cotyledons except on day 3. The maximum uptake of label was on day 3 in the SF cotyledons, which released the highest amount of 14CO2 as well. 14C from the labeled putrescine was incorporated mainly into γ-aminobutyric acid, aspartate and glutamate. High performance liquid chromatography of the endogenous polyamines indicated that spermidine was the most predominant polyamine in the cultured cotyledons of radiata pine. Spermine increased by about 60% in the SF and 25% in the NSF cotyledons between days 0 and 3 of culture.

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