Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Responses of two Populus clones to elevated atmospheric CO concentration in the field 2. | 493 Ann. For. Sci. 56 1999 493-500 Inra Elsevier Paris Original article Responses of two Populus clones to elevated atmospheric CO2 concentration in the field Roberto Tognett Anna Longobuccob Antonio Raschia Franco Migliettaa Ivano FumagallF a Istituto per I Agrometeorologia e 1 Analisi Ambientale applicata all Agricoltura CNR-IATA via Caproni 8 1-50145 Firenze Italy bCeSIA Accademia dei Georgofili Logge Uffizi Corti 50122 Firenze Italy c ENEL Ricerche via Reggio Emilia 39 20093 Milano Italy Received 26 February 1998 accepted 8 March 1999 Abstract - Two poplar clones hybrid Populus deltoides Bartr. Ex Marsh X Populus nigra L. Populus X euramericana clone 1-214 and Populus deltoides clone Lux were grown from clonal hardwood cuttings for one growing season in either ambient 360 pmol mol- or elevated 560 pmol mo - CO in FACE-system rings at Rapolano Terme Siena Italy . Both clones 1-214 and Lux exhibited a higher above-ground biomass photosynthesis at light saturation and instantaneous transpiration efficiency ITE in CO2-enriched air. The elevated CO2 -induced responses of clone 1-214 included increased investment in branch and leaf biomass and enhanced stem volume. The elevated CO2 -induced responses of clone Lux included an increase in the number of branches and leaf area which might result in a higher leaf area index LAI . Photosynthetic acclimation under elevated CO2 was found only during the early morning and only in clone 1-214. Stomata conductance and transpiration on a leaf area basis decreased under elevated CO particularly in clone Lux and at the end of the experiment. The effects of elevated CO2 on leaf osmotic potential were limited at least in conditions of non-limiting water availability. Clonal differences in response to elevated CO2 should be taken in account when planning future poplar plantations in the forecast warmer and drier Mediterranean sites. Inra Elsevier Paris. biomass elevated CO2 FACE-system gas exchange Populus I volume index water .
