The Influence of Dwarfing Interstocks on the Distribution and Metabolism of Xylem-Applied [3H]Gibberellin A4 in Apple

AUTOR(ES)
RESUMO

The influence of an interstock of the dwarfing cultivar M9 and the nondwarfing cultivar MM115 on the distribution and metabolism of labeled gibberellic acid A4 ([3H]GA4) of high specific radioactivity (5.18 × 1010 becquerel per millimole) applied to the xylem of the rootstock in grafted apple (Malus × domestica Borkh.) trees was compared. Free [3H] GA-like metabolites of [3H]GA4, including putative GA1, GA2, GA3, and GA34, as well as various 3H-putative GA glucosyl conjugates were detected in stem segments from both cultivars. M9 interstocks reduced the total uptake of [3H]GA4 and decreased the proportion of 3H metabolites transported to the shoots and leaves of scions. The M9 interstock tissue and adjacent rootstock and scion tissue retained a much greater amount and a higher proportion of the label than did comparable tissue of the nondwarfing MM115 interstock. In addition, the amount and proportion of free [3H]GAs was higher, and the proportion of putative [3H]GA glucosyl conjugates lower, in M9 interstocks compared to MM115. These effects of the dwarfing interstock on GA distribution and metabolism indicate a significant role for GAs in any satisfactory explanation of the dwarfing mechanism in apple.

ACESSO AO ARTIGO

Documentos Relacionados