Resumo

RAMIREZ, Homero et al. Fruit Bud Initiation in Apple cv Red Delicious Linked to Gibberellins and Cytokinins. Rev. Soc. Quím. Méx [online]. 2004, vol.48, n.1, pp.07-10. ISSN 0583-7693.

This work was designed with the purpose to learn more about the presence and possible role of gibberellins and cytokinins in flower formation on apple cv Red Delicious. The presence of endogenous cytokinins was detected in immature seeds. These hormones presumably are produced in these tissues since extremely low cytokinin activity was found in xylem sap at the physiological stage when seeds were analyzed. The application of exogenous cytokinins to spurs at the time of flower initiation, increased the amount of flowers number. The radioactivity of labeled cytokinin injected to spurs, accumulated mainly in the bourse bud. The presence of endogenous gibberellins was also found in seeds; however their level was lower than cytokinins. The gibberellin content was slightly higher than cytokinins in xylem sap. When [³H]-GA₄ was applied to seeds of fruits, higher radioactivity was found in the bourse bud. The gas chromatography-mass spectrometry analysis detected gibberellins A₁, A₄, iso-A₇, A₁₅, A₂₀, A₄₄ and A₅₃ in 42 days old seeds. These results are discussed in relation to flower bud initiation in apple.

Palavras-chave : Malus domestica; endogenous hormones; flower formation.