Cytokinin inhibition ofArabidopsisroot growth: An examination of genotype, cytokinin activity, and N6-benzyladenine metabolism
✍ Scribed by C. A. Auer
- Publisher
- Springer
- Year
- 1996
- Tongue
- English
- Weight
- 515 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0721-7595
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✦ Synopsis
The effects of cytokinins on the in vitro growth of the roots of Arabidopsis thaliana seedlings were examined. Root growth was inhibited in a manner dependent upon the type of cytokinin compound, the cytokinin concentration, the Arabidopsis genotype, and the duration of exposure to cytokinin. For the cytokinins N6-benzyladenine (BA), isopentenyl adenine (iP), or dihydrozeatin (DHZ), the concentration required for 50% root growth inhibition differed for each cytokinin and in each of three Arabidopsis genotypes tested, iP was the most active cytokinin in inhibiting the root growth of the Ler-0 genotype, whereas iP and BA had equal activity when tested with the Col-2 and Columbia genotypes. DHZ had the lowest activity of the three cytokinins tested in all three genotypes. A brief 1-day exposure of seeds to a root-inhibiting concentration of BA increased root growth compared with seedlings grown without BA; exposure to BA for 3-6 days inhibited root growth. BA metabolism was evaluated after 6 h and 1, 3, and 6 days in Columbia seedlings. BA, N6-benzyladenosine (BAR), and N6-benzyladenosine-5'-monophosphate (BAMP) decreased with time, whereas N6-benzyladenine-7-[3-Dglucopyranoside (BA-7-G) and N6-benzyladenine-9-[3-Dglucopyranoside (BA-9-G) accumulated in the growing seedlings. Seven aromatic cytokinins were compared at 5 g,M for their effect on Col-3 root growth. BA, BAR, N6-(m-hydroxybenzylamino)adenine, and N6-(ohydroxybenzylamino)adenine were highly effective in inhibiting root growth, whereas N6-(p-hydroxybenzyl -