tailieunhanh - Báo cáo khoa học: "Whole shoot hydraulic resistance in Quercus species measured with a new high-pressure flowmeter"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Whole shoot hydraulic resistance in Quercus species measured with a new high-pressure flowmeter. | Ann Sci For 1993 50 417-423 Elsevier INRA 417 Original article Whole shoot hydraulic resistance in Quercus species measured with a new high-pressure flowmeter MT Tyree 1 B Sinclair 2 p Lu 3 A Granier 3 1 us Department of Agriculture Forest Service Northeastern Forest Experiment station POBox 968 Burlington Vermont 05402 USA 2INRA Laboratoire de Physiologie Intégrée de I Arbre Fruitier 63039 Clermont-Ferrand 3 INRA Laboratoire d Ecophysiologie Forestière 54280 Champenoux France Received 16 December 1992 accepted 21 April 1993 Summary Whole shoot resistance to water flow was measured in 4 species of oak Quercus ro-bur L o petraea Matt Liebl o pubescens Willd and Q rubra L. Shoots were to m long with 16-19 mm basal wood diameter and were 4-8 yr old. Whole shoot resistances accounted for 2040 of the total resistance to water flow from soils to leaves based on comparisons with literature values. Leaf blade resistances accounted for 80-90 of total shoot resistances measured in this study. Stem resistances to water flow were twice as large in Q robur than in the other species which had comparable stem resistances. Differences in shoot resistance between Q robur versus Q petrae are discussed in terms of the differential response of these species to drought in mixed stands. Quercusl hydraulic resistance water stress Résumé Mesure de la résistance au transfer de I eau Chez ditíérentes espèces de chênes au moyen d un nouveau tluxmètre haute pression. La résistance au transfer de I eau de branches a été mesurée Chez 4 espèces de chênes Quercus robur L Q petraea Matt Liebl Q pu-bescens Willd et Q rubra L. Les branches avaient une longueur comprise entre 1 1 et 1 5 m pour un diamètre de 16 à 19 mm à leur base et étaient âgées de 4 à 8 ans. La comparaison des mesures avec des données de la littérature a montré que la résistance au transfer de I eau dans les branches était de I ordre de 20 à 40 de la resistance hydraulique totale calculée entre le sol et les feuilles. La .