Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Evidence of osmoregulation in Larix decidua at Alpine treeline and comparative responses to water availability of two co-occurring evergreen species. | 623 Ann. For. Sci. 57 2000 623-633 INRA EDP Sciences Original article Evidence of osmoregulation in Larix decidua at Alpine treeline and comparative responses to water availability of two co-occurring evergreen species Alessandro Badalottia 5 Tommaso Anfodillob and John Gracea a University of Edinburgh Institute of Ecology and Resource Management Darwin Building Mayfield Road Edinburgh EH9 3JU Scotland . b Dipartimento Territorio e Sistemi Agro Forestali University of Padova Agripolis Via Romea 16 35020 Legnaro PD Italy Received 18 November 1999 accepted 12 May 2000 Abstract - The water relations of three coniferous species Larix decidua Picea abies and Pinus cembra growing at a treeline ecotone in the Southern Alps were investigated. Sap flux and xylem water potential were measured in two individuals of each of the above-mentioned species during part of summer 1997. Throughout the growing period L. decidua showed a gradual decrease in minimum water potential while for P. abies and P. cembra variations were more correlated to actual weather conditions. Daily sap flux was also higher in L. decidua than in the two other species. Pressure-volume curves derived for L. decidua during July 1997 demonstrated that the species further diminished its minimum water potential through osmoregulation. During dry periods the other species showed an evident reduction in sap flux suggesting a water saving behaviour. The three species seem therefore to have evolved different drought avoidance strategies. osmotic adjustment Pinus cembra Picea abies sap flow pressure-volume curves Résumé - Evidence d un ajustement osmotique chez Larix decidua à la limite de l etage forestier alpin et réponses comparées à la disponibilité en eau de deux espèces de conifères co-existantes. On a étudié les strategies hydriques de trois espèces de coni-fères Larix decidua Picea abies et Pinus cembra qui poussent dans un écotone à la limite supérieure de l etage forestier dans le sud des Alpes. On a .
