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 Faÿ
1992 Annales des Sciences Forestieres  
— Primary and secondary growths of main and lateral axes of 1-year-old Terminalia superba Eng I 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
more » ... . 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 treesresulting 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 successive sink/source roles of the uppermost tier of branches for metabolites. This growth-habit was observed under favourable environmental conditions. At the end of the long dry season, it was not so obvious, since shoot growth could cease for a couple of weeks and radial growth slowed down slightly. main stem-branch growth / radial and shoot growth I rhythmicity / Terminalia superba / tropical tree Résumé — Développement végétatif, croissance primaire et secondaire du système caulinaire de jeunes arbres tropicaux de l'espèce Terminalia superba, dans un environnement naturel. II. Croissance terminale, croissance latérale et corrélations de croissance tige principale-branche. Les croissances primaire et secondaire des axes principaux et latéraux de Terminalia superba Engl et Diels âgés de 1 an, ainsi que quelques aspects du développement végétatif, furent étudiés dans un environnement naturel tropical et suivis sur une période de 6 mois. Durant la grande saison des pluies, la croissance primaire des tiges principales était continue, mais les perba / arbre tropical
doi:10.1051/forest:19920408 fatcat:y37y356fcbgbvmipkw4dcqzxmm