tailieunhanh - Báo cáo khoa học: "Water relations of adult Norway spruce (Picea abies (L) Karst) under soil drought in the Vosges mountains: water potential, stomatal conductance and transpiration"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài:"Water relations of adult Norway spruce (Picea abies (L) Karst) under soil drought in the Vosges mountains: water potential, stomatal conductance and transpiration. | Ann Sei For 1995 52 117-129 Elsevier INRA 117 Original article Water relations of adult Norway spruce Picea abies L Karst under soil drought in the Vosges mountains water potential stomatai conductance and transpiration p Lu 1 p Biron 2 N Bréda 1 A Granier1 INRA laboratoire d ecophysiologie et bioclimatologie 54280 Champenoux 2 CEREG ULP 3 rue de I Argonne 67000 Strasbourg cedex France Received 27 February 1994 accepted 26 July 1994 Summary The effects of soil water depletion on sap flow twig water potential stomatai and canopy conductance were analysed in 2 plots of a 30-year-old stand of Norway spruce. One was subjected to an imposed drought the other was watered by irrigation. Predawn water potential in trees from the dry plot decreased to MPa. In the watered plot a low between-tree variability of sap flux density was observed with maximum values of dm3 dm-2 h-1 corresponding to about mm h-1. In the dry plot sap flux density showed a higher variability and decreased during the summer to a minimum midday value of dm3 dm-2 h-1. Tree transpiration and stomatai conductance showed a strong reduction in association with drought development during which the predawn water potential decreased from to MPa. Canopy conductance was calculated from the reverse of the Penman-Monteith equation assuming that vapour flux over the stand was equal to the estimated stand sap flow. Effects of climatic factors and drought on canopy conductance variations were taken into account in a multi-variable transpiration model. transpiration stomatai conductance canopy conductance water potential drought sap flow Picea abies Correspondence and reprints. Abbreviations KFf twig water potential MPa Tpd T m predawn and diurnal minimal twig water potential MPa respectively Fd xylem sap flux density dm3 dm-2 h-1 F total xylem sap flow dm3 fr1 SA sapwood area dm2 Tw Td transpiration of watered and dry plot mm tr1 Rim d-1 respectively TM maximal plot transpiration mm-h T