tailieunhanh - Báo cáo khoa học: "Vegetative development, primary and secondary growth of the shoot system of young Terminalia superba tropical trees, in a natural environment. II. Terminal growth, lateral growth and main stem-branch growth correlations"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài:"Vegetative development, primary and secondary growth of the shoot system of young Terminalia superba tropical trees, in a natural environment. II. Terminal growth, lateral growth and main stem-branch growth correlations. | 403 AnnSciFor 1992 49 403-422 Elsevier INRA Original article Vegetative development primary and secondary growth of the shoot system of young Terminalia superba tropical trees in a natural environment. II. Terminal growth lateral growth and main stem-branch growth correlations E de Fay Université de Nancy I Laboratoire de biologie des Ligneux BP 239 54506 Vandoeuvre-lès-Nancy Cedex France Received 22 July 1991 accepted 17 April 1992 Summary Primary and secondary growths of main and lateral axes of 1-year-old Terminalia superba Engl and Diels trees as well as some other aspects of vegetative development were studied in a natural tropical environment and followed for a period of 6 months. During the long rainy season primary growth of main axes was continuous but the rates of shoot elongation and leaf emergence fluctuated rhythmically and correlatively. Shoot elongation rhythm often lagged a little behind leaf emergence rhythm. In addition leaf development was homoblastic. Lateral shoots appeared when leaf emergence was at a maximum consequently they were arranged in successive tiers pseudowhorls of branches . The apposition of sympodial units in the developing tier of the trees -resulting in the typical Terminalia branching - did not depend on the existence of the main apex but it was limited as soon as new lateral axes branched above the tier in question. From that time the activity of branch apices and the radial growth of branch bases ceased or at least were not detected further. Radial growth of trunks was continuous but the growth rate of the upper parts changed in relation to the occurrence of tiers. Reiteration of the main apex in an accidentally decapitated plant was late it occurred after the uppermost branch tier had reached a large size. These results indicate different types of growth correlation in the shoot system of young Terminalia superba trees. It is suggested that the particular growth features of this species are related to the presumably .