tailieunhanh - Báo cáo khoa học: "Xylem hydraulic efficiency versus vulnerability in seedlings of four contrasting Mediterranean tree species (Cedrus atlantica, Cupressus sempervirens, Pinus halepensis and Pinus nigra)"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Xylem hydraulic efficiency versus vulnerability in seedlings of four contrasting Mediterranean tree species (Cedrus atlantica, Cupressus sempervirens, Pinus halepensis and Pinus nigra). | Ann. For. Sci. 59 2002 409-418 INRA EDP Sciences 2002 DOI forest 2002015 409 Original article Xylem hydraulic efficiency versus vulnerability in seedlings of four contrasting Mediterranean tree species Cedrus atlantica Cupressus sempervirens Pinus halepensis and Pinus nigra Fabienne Frouxa b Roland Huca Michel Ducreya and Erwin Dreyerb aINRA Unité de Recherches Forestières Méditerranéennes Avenue A. Vivaldi 84000 Avignon France b UMR INRA-UHP Écologie et Écophysiologie Forestières 54280 Champenoux France Received 5 November 2001 accepted 11 February 2002 Abstract - We studied the xylem hydraulic traits and anatomy of four diverse Mediterranean conifers to determine how these species protect themselves against catastrophic xylem failure. Cedrus atlantica Cupressus sempervirens Pinus nigra and P. halepensis seedlings were grown for two years in pots in a greenhouse under well-watered conditions. Measurements were conducted in April and September. The vulnerability to cavitation was lower in April in the two pines and cedar whereas the conductivity was lower in the two pines and cypress. There were also large species differences in vulnerability to cavitation in September loss of 50 conductivity occurred at MPa in P. nigra MPa in C. atlantica MPa in C. sempervirens and MPa in P. halepensis. Leaf specific hydraulic conductivity was much higher in Cupressus sempervirens and P. nigra than in Cedrus atlantica and P. halepensis. No trade-off between xylem safety low vulnerability and efficiency high hydraulic conductivity was found among the four species. Specific conductivity was directly related to hydraulic mean tracheid lumen diameter while xylem vulnerability appeared to be independent of tracheid size. xylem embolism hydraulic conductivity xylem anatomy Mediterranean conifers Résumé - Efficience hydraulique et vulnérabilité de plantules de quatre espèces de coniferes méditerranéens Cedrus atlantica Cupressus sempervirens Pinus halepensis .