tailieunhanh - Báo cáo lâm nghiệp: "Correlative control of early stages of flower bud initiation in ’bourse’ shoots of apple (Malus x domestica Borkh. cv. Golden Deliciou"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Correlative control of early stages of flower bud initiation in ’bourse’ shoots of apple (Malus x domestica Borkh. cv. Golden Delicious). | 44s Ann. Sci. For. 1989 46 suppl. 44s-46s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Correlative control of early stages of flower bud initiation in bourse shoots of apple Malus X domestica Borkh. cv. Golden Delicious J. Escobedo and J. Crabbé Morphogénèse végétale appliquée Faculte des Sciences agronomiques Gembloux Belgique Introduction A better understanding of flowering in fruit trees would be obtained if we could predict where and when a flower is to appear. This is particularly true in those locations where flowering occurs for the first time they can be predicted Crabbé 1984 with a satisfying probability for fruit growers purposes but any precise physiological or biochemical approach requires more than mere probability. Consequently although the start of floral initiation is rather accurately known in fruit species sound information about floral induction and evocation is still lacking. As a preliminary to this necessary prediction problem we began experimenting on apple bourse shoots. The bourse is the swollen basal part of an inflorescence axis at the onset of fruit development it bears leaves whose axillary buds differentiate and may grow out as shoots. The bourse shoot can flower again in the following years and so by repeated flowering a cluster of stacked similar structures appears on old trees. Once formed a bourse is thus a known site for renewed floral induction. There may be year-to-year irregularities due to competition with fruit growing at the same site alternate bearing or with nearby vegetative growth. Our objectives were to determine what treatments could cause 90-100 of bourse buds to shift from the vegetative to the floral state and to define precocious signs of this change in meristematic activity. Materials and Methods Six yr old apple trees cv. Golden delicious were used throughout. Bourses formed in the current year on which young fruits were developing were labeled in early spring. Later some bourses with short arrested