tailieunhanh - Báo cáo lâm nghiệp: "Experimental control in Weigela japonica of flower initiatiob"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Experimental control in Weigela japonica of flower initiation. | 34s Ann. Sci. For. 1989 46 suppl. 34s-36s Forest Tree Physiology E. Dreyer et a . eds. Elsevier INRA Experimental control of flower initiation in Weigela japonica M. Bodson Centre de PhysiologieVégétale Appliquée IRSIA Université de Liège Institutde Botanique B22 Sart Tilman B-4000 Liège Belgium Introduction Most of the experimental work on the mechanisms controlling flowering are reported for herbaceous annuals for which floral transition is under photoperiodic control. Experimentation with these species has emphasized the importance of the leaf system for the perception of the proper photoperiod and made clear that the leaf processes resulting in the synthesis of the flowering stimulus are a major control point of the floral transition Zee-vaart 1976 Bernier 1988 . Several characteristics are specific to the floral transition of woody perennials. For most woody species of the temperate zone 1 flowers are initiated on resting axillary buds 2 there is a long rest period between flower initiation and anthesis 3 there is no direct control of flower initiation by the daylength while vegetative growth may be under strong photoperiodic control Nitsch 1957 and 4 the floral response is localized to certain buds Jackson and Sweet 1972 Buban and Faust 1982 . The causes of this localization of the floral response are still largely unknown and may be related to physiological conditions internal to the bud Hornberger 1963 Crabbe 1984 . One may thus suspect that the floral transition of woody species is controlled by specific mechanisms not found in photoperiodic annuals. A study has been started with Weigela japonica a woody ornamental to consider some aspects of this question. Results are reported on the effect of a pruning treatment on the floral response of resting axillary buds. Two points were investigated 1 the floral response with regard to the age of the buds located at a similar node position and 2 the floral response at a single time of pruning applied at different .