tailieunhanh - Báo cáo khoa học: "Hydraulic conductance of root and shoot measured with the transient and dynamic modes of the high-pressure flowmete"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Hydraulic conductance of root and shoot measured with the transient and dynamic modes of the high-pressure flowmeter. | Ann. For. Sci. 59 2002 389-396 INRA EDP Sciences 2002 DOI forest 2002010 389 Original article Hydraulic conductance of root and shoot measured with the transient and dynamic modes of the high-pressure flowmeter Marie-Béatrice Bogeat-Triboulota Rodolphe Martina David Chateleta and Hervé Cochardb a UMR INRA-UHP Écologie et Écophysiologie Forestières INRA 54280 Champenoux France bUMR 547 PIAF INRA-UBP Site de CroUelle 63039 Clermont-Ferrand cedex 02 France Received 18 September 2001 accepted 8 February 2002 Abstract - The hydraulic conductance k of shoots and root systems was measured using the transient and the dynamic modes of the high pressure flowmeter HPFM . Measurements were conducted on Quercus robur and Fagus sylvatica plants grown on different substrates forest soil sand Terra-green and vermiculite and harvested at different times of the year. The values of k obtained by the transient mode were compared to those obtained by the dynamic mode. A tight 1 1 correlation was observed for shoots and defoliated stems but several types of discrepancies appeared for root systems. The underestimation of k by the dynamic mode as compared to the transient mode could be explained by reverse osmosis at the endodermis. However the transient mode was not functional for some root systems. This problem occurred essentially in small plants harvested early in the year before budbreak had been completed. Nature and origins of problems are discussed. hydraulic conductance high pressure flowmeter transient mode root shoot Résumé - Mesure de la conductance hydraulique des parties aériennes et des systèmes racinaires avec les modes transitoire et dynamique du fluxmetre haute pression. La conductance hydraulique des parties aériennes et des systèmes racinaires a été mesurée avec le fluxmètre haute pression HPFM en mode transitoire et en mode dynamique. Les mesures ont été effectuées sur des plants de Quercus robur et de Fagus sylvatica ayant poussé sur différents substrats sol