tailieunhanh - Báo cáo lâm nghiệp: "Water relations of oak species growing in the natural 2 CO spring of Rapolano (central Italy) "

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế, đề tài: "Water relations of oak species growing in the natural 2 CO spring of Rapolano (central Italy) . | Ann Sci For 1996 53 475-485 Elsevier INRA 475 Original article Water relations of oak species growing in the natural co2 spring of Rapolano central Italy R Tognetti1 2 A Giovannelli 2 A Longobucco 3 F Miglietta 3 A Raschi 3 Ce SIA Accademia dei Georgofili Logge degli Uffizi Corti 50122 2 IMGPF Consiglio Nazionale delle Ricerche Via Atto Vannucci 13 50134 3 IATA Consiglio Nazionale delle Ricerche Piazzale delle Cascine 18 50144 Florence Italy Received 2 January 1995 accepted 3 October 1995 Summary The effect of elevated atmospheric carbon dioxide on water relations was examined on downy oak Quercus pubescens and holm oak Q ilex trees. The study was conducted on trees growing in a naturally enriched co2 spring. Sap velocity and sap flow were measured by the heat pulse technique. On the same trees daily courses of xylem water potential leaf conductance and transpiration were monitored. Plant water relations were evaluated by pressure-volume analysis method on shoots on the same branches relative conductivity of xylem was measured. Both species exhibited increased osmotic potential and decreased symplasmic fraction of water in trees adapted to increased co2. Downy oak showed lower stomatai conductance under elevated co2 but holm oak did not. Both species displayed higher sap flow in control trees. In both species increased carbon dioxide did not influence xylem embolism formation. drought elevated co21 embolism Quercus ilex I Quercus pubescens I sap flow I water relations Resume Relations hydriques de deux espèces de chênes poussant près d une source enri-chie en co2. L effet de I enrichissement de atmosphere en co2 sur les relations hydriques du Quer-cus pubescens et du Q ilex a été étudié. Les mesures ont été réalisées au cours de 1 état sur des arbres poussant près d une source enrichie naturellement en co2. Les flux de save brute ont été mesurés par la technique de impulsion de chaleur sur les mêmes arbres les cinétiques ịournalières de potentiel hydrique foliaire