02788naa a2200157 a 450000100080000000500110000800800410001910000110006024501800007126000090025152021740026065300150243465300150244965300320246477301340249610822812011-11-30       2004    bl uuuu     u00u1 u    #d1 aEpagri  aInfluence of chilling amounts on budbreak patterns on the one-year-old shoot of peach tree and dynamics of physiological and biochemical parameters related to dormancy course.  c2004  aUnder the soft winter conditions of tropical and subtropical zones, varieties of temperate fruit trees, if not well adapted, suffer agronomic problems resulting from heterogeneous budbreak and flowering (in temperate zones they could experience such problems with increasing intensity in future owing to global warming). Using experimental conditions providing trees with regular (R) or limited (L) chilling amounts before they experienced forcing temperatures (respectively trees at the orchard or trees in containers moved at the beginning of December from outside into a heated greenhouse), the influence of these amounts on the budbreak pattern of ?Redhaven? peach trees was investigated, with special regards to the foregoing dynamics of development of the buds and related physiological and biochemical parameters according to their place along the twig. Individual vegetative and floral budbreak was recorded in planta. Leaf bud endodormancy was characterized using the ?cuttings? test. Growth rhythm of floral buds before budbreak was estimated from the dry weight of floral primordia. The water content of the vegetative and floral buds was computed. The energy metabolism of the primordia zones was characterized through respiration rate measurement (microcalorimetry method) and ATP (and ADP) assays (bioluminescence method). Starch, sucrose, sorbitol, fructose and glucose were assayed for characterizing carbohydrate state in the buds. Under the L and R treatments budbreak rate and patterns were different: global final rate respectively low and high, distribution along the twig respectively basitonic and even. Data confirmed that ATP contents could be an interesting marker of the growth capacity of the buds in planta and indicated that respiration rate could be as well such a marker. The data of the various parameters indicated that under the different treatments the budbreak patterns depended on the release patterns of bud endodormancy, in time as well as in space. Depending the chilling amounts applied, the budbreak patterns could depend either on the dynamics of endodormancy release or on processes taking places after endodormancy release.  aBrotação  aDormência  aQuantidade de frio hibernal  tIn: INTERNATIONAL SYMPOSIUM ON PLANT DORMANCY, 3., 2004, Wageningen. Abstracts... Wageningen: Wageningen University, 2004. p. 47.