tailieunhanh - Báo cáo lâm nghiệp: "Stomatal response of Quercus pyrenaica Willd to environmental factors in two sites differing in their annual rainfall (Sierra de Gata, Spain)"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế, đề tài:"Stomatal response of Quercus pyrenaica Willd to environmental factors in two sites differing in their annual rainfall (Sierra de Gata, Spain). | Ann Sci For 1996 53 221-234 Elsevier INRA 221 Original article Stomatai response of Quercus pyrenaica wind to environmental factors in two sites differing in their annual rainfall Sierra de Gata Spain M Rico HA Gallego G Moreno I Santa Regina Institute de Recursos Naturales y Agrobiologia CSIC Apdo 257 37071 Salamanca Spain Received 6 September 1994 accepted 17 July 1995 Summary Quercus pyrenaica natural forests located in the Sierra de Gata Salamanca Province Spain were studied. Two permanent sampling sites were selected at the two extremes of a rainfall gradient in this area. Diurnal courses of transpiration rate stomatai conductance and leaf water potential were determined approximately every 2-3 weeks in 1991 and 1992 during the active leaf period at different levels in the tree canopy. Current variations in photosynthetically active radiation PAR incident to the leaf surface air and leaf temperature vapour pressure deficit VPD and soil moisture were also measured. Boundary-line response curves between leaf conductance and four variables were studied to determine the general stomatai response patterns. Leaf conductance increased rapidly at first with small increases in PAR. Above 50 pmol ITT2 S 1 no additional increases in conductance were observed. The optimum temperature ranged between 18 and 22 C. Conductance remained constant at low and moderate VPD values and strongly decreased after a given threshold value KPa . The response was sharper at the humid site. Beyond a threshold leaf water potential level -2 MPa stomatai conductance decreased rapidly as water potential continued to decline. Quercus pyrenaicaf stomatai conductance leaf water potential deciduous oak Resume Réponse stomatique de Quercus pyrenaica Wil Id aux facteurs de I environnement dans deux forets different par la pluviosité annuelle Sierra de Gata Espagne . Cette étude a été menée dans des forets naturelies de Quercus pyrenaica wind situées dans la Sierra de Gata province de Salamanque .

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