Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: S relationships for carbon and nitrogen during early growth of Juglans regia L. seedlings: analysis at two elevated CO concentrations 2. | 59 Ann. For. Sci. 56 1999 59-69 Inra Elsevier Paris Original article Source-sink relationships for carbon and nitrogen during early growth of Juglans regia L. seedlings analysis at two elevated CO2 concentrations Pascale MaillarcP Eliane Deléensb Frederic CastelF Franẹois-Alain Daudeta Laboratoire de physiologie intégrée de 1 arbre fruitier Inra Domaine de Crouelle 63039 Clermont-Ferrand cedex 02 France h Laboratoire de structure et de métabolisme des plantes CNRS ERS 569 Université Paris XI 91405 Orsay cedex France Received 5 February 1998 accepted 8 June 1998 Abstract - Assimilation and allocation of carbon C and nitrogen N were studied in seedlings Juglans regia L. grown for 55 days under controlled conditions 22 C 12 h 90 relative humidity RH using two CO2 concentrations 550 and 800 pL L_ CO2 . c and N decrease in seeds was unaltered by co . At the end of seed contribution day 35 c and N accumulation in seedlings was favoured under 800 pL L 1 CO I resulting in an increase of about 50 for c and 35 for N. Growth enhancement was larger in roots than in shoot resulting in a higher root shoot ratio R S with respect to 550 pL L co R S at day 55. These results were due in order to 1 a shoot respiration temporarily depressed by CO 2 a reduction by 46 of the root soil respiration 3 a stimulation by 14 of the C assimilation and 4 an increased uptake and assimilation of N coming from the rooting medium. An increased use of N originated from the seed was observed in leaves and lateral roots suggesting optimisation of distribution of stored N pools by seedlings. These changes finally gave rise to an increased C N ratio for taproot 27 roots 20 stem 28 and leaves 12 suggesting a N dilution in the tissues. Inra Elsevier Paris. Juglans regia I CO2 c balance 15N shoot root Resume - Relations source-puits pour le carbone et 1 azote durant les premiers stades de croissance de semis de Juglans regia L. analyse à deux concentrations en CO2atmosphérique élevées. L .
