Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Do trees use reserve or newly assimilated carbon for their defense reactions? A 13 C labeling approach with young Scots pines inoculated with a bark-beetle-associated fungus (Ophiostoma brunneo ciliatum). | Ann. For. Sci. 64 2007 601-608 INRA EDP Sciences 2007 DOI forest 2007038 Available online at Original article Do trees use reserve or newly assimilated carbon for their defense reactions A 13C labeling approach with young Scots pines inoculated with a bark-beetle-associated fungus Ophiostoma brunneo ciliatum Natacha GUÉRARDa b Pascale MAlLLARDb Claude BrECHETb Francois LlEUTlERa c Erwin DREYERb a INRA Unité de Zoologie Forestière INRA Orleans Avenue de la Pomme de Pin BP 20619 45166 Ardon Cedex France b INRA UMR1137 INRA-UHP Écologie et Écophysiologie Forestières IFR 110 Génomique Écophysiologie et Écologie Fonctionnelle INRA Nancy 54280 Champenoux France c Laboratoire de Biologie des Ligneux et des Plantes de Grande Culture Université d Orleans BP 6759 45067 Orleans Cedex 2 France Received 12 October 2006 accepted 24 January 2007 Abstract - Three-year-old saplings of Pinus sylvestris L. were labeled with 13CO2 prior to inoculating the trunk with Ophiostoma brunneo ciliatum a blue-staining fungus usually associated to Ips sexdentatus. During incubation half the trees were submitted to a severe drought that decreased photosynthesis and natural 13C content in non-labeled saplings. A large 13C-excess was obtained in wood and phloem especially in the fractions of soluble proteins starch and soluble sugars of labeled saplings. Drought increased 13C-excess due to reduced photosynthesis and smaller dilution of 13C by the addition of newly assimilated 12C. The induced-reaction zones in inoculated saplings displayed large total C 58 g 100 g-1 because of the accumulation of secondary metabolites. They also showed much larger 13C-excess than any other compartment the contribution of stored C to the reaction zones was much higher than that of currently assimilated C. Moreover drought lowered the contribution of the latter as shown by the increase of 13C in the reaction zones. We conclude that stored C was readily mobilized for the construction of .
