Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: "Light acclimation and photosynthetic response of beech (Fagus sylvatica L.) saplings under artificial shading or natural Mediterranean conditions" | Ann. For. Sci. 63 2006 257- 266 INRA EDP Sciences 2006 DOI forest 2006004 257 Original article Light acclimation and photosynthetic response of beech Fagus sylvatica L. saplings under artificial shading or natural Mediterranean conditions Julien PARELLEa b Jean-Philippe RoUDAUTa Michel DUCREYa a INRA Unité de Recherches Forestières Méditerranéennes Avenue A. Vivaldi 84 000 Avignon France b Present address UMR INRA-UHP Écologie et Écophysiologie Forestières INRA - Centre de Nancy 54280 Champenoux France Received 23 June 2005 accepted 29 September 2005 Abstract - Acclimation of beech Fagus sylvatica L. to different light conditions was studied in natural regeneration below black pine canopies Pinus nigra ssp. nigricans in Mont-Ventoux Vaucluse France and with potted saplings - from the same origin - under shaded tunnels in southern France Avignon Vaucluse and north-eastern France Nancy Meurthe-et-Moselle . Leaf mass to area ratio and leaf carbon content per unit mass increased while leaf nitrogen content per unit mass Nm remained constant with increasing relative irradiance RI . Maximum carboxylation rate Vcmax and maximum electron transport flux 7max increased with RI and were higher in the natural regeneration than in the potted saplings. These two parameters were higher for the potted saplings in north-eastern France than for those in southern France. Leaf nitrogen allocation to carboxylation Pr or bioenergetics Pb did not vary with RI. Pr and Pb were higher in the natural regeneration than in the potted saplings whereas Nm was lower in the natural regeneration than in the fertilised potted saplings. Seasonal time course of these parameters in the natural regeneration in Mont-Ventoux from bud burst to the beginning of summer drought showed that after the leaf expansion period leaf composition and photosynthetic parameters remain globally constant. maximum carboxylation rate Tcmax maximum electron transport flux Jmax nitrogen allocation relative irradiance
