Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Responses of growth, nitrogen and carbon partitioning to elevated atmospheric CO concentration in live oak 2 (Quercus virginiana Mill.) seedlings in relation to nutrient supply Roberto. | 91 Ann. For. Sci. 56 1999 91-105 Inra Elsevier Paris Original article Responses of growth nitrogen and carbon partitioning to elevated atmospheric CO2 concentration in live oak Quercus virginiana Mill. seedlings in relation to nutrient supply Roberto Tognettia b Jon D. Johnson3 a School of Forest Resources and Conservation University of Florida 326 Newins-Ziegler Hall Gainesville FL 32611 USA b Istituto per 1 Agrometeorologia e I Analisi Ambientale applicata aH Agricoltura Consiglio Nazionale delle Ricerche via Caproni 8 50145 Florence Italy and Department of Botany Trinity College University of Dublin Dublin 2 Ireland Received 9 February 1998 accepted 22 July 1998 Abstract - Live oak Quercus virginiana Mill. seedlings were exposed at two concentrations of atmospheric carbon dioxide CO2 370 or 520 pmol-mol 1 in combination with two soil nitrogen N treatments 20 and 90 pmol-mol 1 total N in open-top chambers for 6 months. Seedlings were harvested at 5-7 weeks interval. CO2 treatment had a positive effect on seedling growth. Differences in biomass between elevated and ambient CO2-treated plants increased over the experimental period. Soil N availability did not significantly affect growth. Nevertheless growth in elevated CO2 in combination with high N levels led to a consistently higher accumulation of total biomass by the end of the experiment 30-40 . Biomass allocation between plant parts was similar for seedlings in all treatments but was significantly different between harvests. The N regimes did not result in different relative growth rate RGR and net assimilation rate NAR while CO2 treatment had an overall significant effect. Across all CO2 and N levels there was a positive relationship between plant mass and subsequent RGR and this relationship did not differ between treatments. Overall specific leaf area SLA decreased in co -enriched air. Fine root-foliage mass ratio was increased by elevated CO2 and decreased by high N. High CO2- and high N-treated plants .
