tailieunhanh - Báo cáo khoa học: "Variation in leaf morphology and branching pattern of some tropical rain forest species from Guadeloupe (French West Indies) under semi-controlled light conditions"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài:"Variation in leaf morphology and branching pattern of some tropical rain forest species from Guadeloupe (French West Indies) under semi-controlled light conditions. | Ann Sci For 1992 49 553-570 Elsevier INRA 553 Original article Variation in leaf morphology and branching pattern of some tropical rain forest species from Guadeloupe French West Indies under semi-controlled light conditions M Ducrey INRA Laboratoire de Recherches Forestieres Méditerranéennes Avenue A Vivaldi F-84000 Avignon France Received 18 March 1992 accepted 7 July 1992 Summary Seedlings of 7 canopy species from the Guadeloupe tropical rain forest Dacryodes excelsa Amanoa caribaea Richeria grandis Simaruba amara Symphonia globulifera Byrsonima coriacea and Podocarpus coriaceus were raised in full sunlight and under artifical neutral shade transmitting 6 11 19 and 54 light for 2 to 3 years. At the end of this period the number of leaves and branches leaf size specific leaf area and stomatai density were observed for each plant. For all species the maximum number of leaves was obtained in partial shade 11 or 19 sunlight . Branching occurrence depended more on species type than on light conditions. Both individual leaf size and specific leaf area increased regularly with shade but in a proportion which varied according to the species. Stomatai density was highly variable from one species to another and increased with greater light. The morphological plasticity of species response to light conditions was then analysed and related to shade tolerance. In order of decreasing plasticity the first species found were R gran-dis s amara and B coriacea which were the most plastic and the most shade intolerant followed by A caribaea and p coriaceus less plastic but shade-tolerant species. Finally D excelsa and s globu-lifera were found to be the least plastic species and highly or moderately shade-tolerant. tropical rain forest leaf morphology I specific leaf area branching pattern shade tolerance Resume Variations de la morphologie foliaire et branchaison de quelques espèces de la foret tropicale humide de Guadeloupe en conditions semi-contrôlées d eclairement. De jeunes