tailieunhanh - Báo cáo khoa học: "Hydraulic conductance of two co-occuring neotropical understory shrubs with different habitat preferences"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Hydraulic conductance of two co-occuring neotropical understory shrubs with different habitat preferences. | 201 Ann. For. Sci. 57 2000 201-208 INRA EDP Sciences Original article Hydraulic conductance of two co-occuring neotropical understory shrubs with different habitat preferences Bettina . Engelbrechta b Virginia Velezb and Melvin T. Tyreec a Technische Universitat Darmstadt Institut fur Botanik Schnittspahnstr. 3-5 64287 Darmstadt Germany b Smithsonian Tropical Research Institute . Box 2072 Balboa Panama c USDA Forest Service Aiken Forestry Sciences Laboratory . Box 968 South Burlington VT 05402 USA Received 29 June 1999 accepted 14 December 1999 Abstract - Whole plant hydraulic conductance was measured for two co-occuring neotropical rainforest understory shrub species of the genus Piper which differ in their habitat preference with respect to soil moisture P. trigonum is restricted to wet habitats whereas P. cordulatum occurs in drier sites. Plants were grown under four treatments two light conditions crossed with two watering regimes representing the extremes of conditions in their natural habitat. The data showed significantly higher total hydraulic conductance and leaf specific conducance in the drought-avoiding species P. trigonum than in the drought-tolerant species P. cordula-tum. The measured parameters also differed between growth treatments. The species differences in hydraulic conductance could be interpreted as adaptive in the respective species habitat and might thus be important in determining habitat preference and distribution of the two species. hydraulic conductance drought Piper tropical rainforest understory shrub Résumé - Conductance hydraulique de deux arbustes néotropicaux du sous étage ayant des habitats préférentiels. La conductance hydraulique de la plante entière a été mesurée pour deux espèces arbustives du genre Piper du sous étage d une forêt néotropi-cale. Ces espèces différent par leur adaptation à l humidité du sol P. trigonum est localisé dans les habitats humides alors que P. cordulatum se rencontre dans les zones sèches.