Tognetti R (1), Longobucco A (1), Raschi A (1), Fumagalli I (2)
Abstract: Two poplar clones, hybrid Populus deltoides Bartr. Ex Marsh x Populus nigra L. (Populus x euramericana), clone I-214, and Populus deltoides, clone Lux, were grown from clonal hardwood cuttings for one growing season in either ambient (360 m mol mol-1) or elevated (560 m mol mol-1) [CO2] in FACE-system rings at Rapolano Terme (Siena, Italy). Both clones I-214 and Lux exhibited a higher above-ground biomass, photosynthesis at light saturation and ITE in CO2-enriched air. The CO2-induced responses of clone I-214 included increased investment in branch and leaf biomass, and enhanced stem volume. The CO2-induced responses of clone Lux included an increase in the number of branches and leaf area (which might result in a higher LAI). We found an indication of photosynthetic acclimation under elevated [CO2] only during the early morning and only in clone I-214. Stomatal conductance and leaf transpiration decreased under elevated [CO2] 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 forecast warmer and drier Mediterranean sites.
Citazione: Tognetti R , Longobucco A , Raschi A , Fumagalli I (1999). Responses of two Populus clones to elevated [CO2] in the field . 2° Congresso Nazionale SISEF, Bologna, 20 – 22 Ott 1999, Contributo no. #c2.6.42