Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Effects of water supply on gas exchange in Pinus pinaster Ait. provenances during their first growing season. | 9 Ann. For. Sci. 57 2000 9-16 INRA EDP Sciences 2000 Original article Effects of water supply on gas exchange in Pinus pinaster Ait. provenances during their first growing season Manuel Fernandez Luís Gil and José A. Pardos Unidad de Anatomía Fisiología y Genética Forestal ETS de Ingenieros de Montes Ciudad Universitaria s n Universidad Politécnica de Madrid 28040 Madrid Spain Received 26 March 1999 accepted 16 July 1999 Abstract - Gas exchange parameters were monitored during the first growing season on Pinus pinaster young seedlings belonging to six provenances and submitted to two water supply regimes in the open air under cover. Significant differences were found between water supply regimes and measurement dates sometimes also between provenances. Gas exchange rate responses to needle water potential were similar for all the provenances and rate changes were only detected as water potential went down to less than MPa. The Iberian provenances in contrast to the Landes showed a tendency to save water at the end of Spring which indicates an adaptation to locations with Summer drought. The growth differences between provenances were not expressed in terms of differences in the instantaneous net photosynthetic rate since this will depend on other factors such as seedling water status and the time that the measurement was made. However provenance growth differences may be partially explained by the differences in water use efficiency and nitrogen productivity. maritime pine early selection gas exchange parameters Résumé - Effets de l alimentation en eau sur les échanges gazeux des provenances de Pinus pinaster Ait. au cours de leur premiere saison de végétation. Les échanges gazeux ont été étudiés au cours de la première saison de végétation de jeunes semis de Pinus pinaster appartenant à six provenances et soumis à deux régimes d alimentation en eau sous couvert en plein air. Des dif-férences significatives ont été trouvées entre les régimes d alimentation en
