Effect of plant growth hormones and polyamines on ornithine decarboxylase activity during the germination of barley seeds |
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Authors: | Dimitrios A Kyriakidis |
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Institution: | D. A. Kyriakidis, Lab. of Biochemistry, Aristotelian Univ. of Thessaloniki, School of Science, Thessaloniki, Greece;. |
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Abstract: | Gibberellic acid (GA3) and β-indolylacetic acid (IAA), two of the well known growth hormones, induce four fold the activity of ornithine decarboxylase (ODC) during the germination of barley seeds ( Hordeum vulgare L. var. Beca). The optimal concentration for induction of ODC was 10–5 M for GA3 and 10–3 M for IAA. When 10–3 M of a polyamine, putrescine or spermidine, is added to the growth medium, ODC activity is significantly inhibited. This inhibition is due to the induction of a protein inhibitor of ODC (antizyme), whose apparent molecular weight is 16 000 ± 2 000 daltons. Addition of GA3 to cultures which have been grown for 50 or 98 h in the presence of polyamines, abolishes the observed inhibition of ODC activity, while in the reverse experiment, addition of polyamines at 50 or 98 h does not affect the ODC activity induced by GA3. Cadaverine, a physiological plant diamine, enhances ODC activity; whereas 1,8-diaminooctane (the alkyl analogue of spermidine) does not have any effect. |
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Keywords: | Antizyme cadaverine 1 8-diaminooctane gibberellic acid β-indolylacetic acid putrescine spermidine |
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