Responses of Populus (clone I-214) and Robinia pseudoacacia to elevated CO2 concentrations in the field
1999
Tognetti, R. | Longobucco, A. | Raschi, A. (Consiglio Nazionale delle Ricerche, Florence (Italy). Istituto per l'Agrometeorologia e l'Analisi Ambientale Applicata all'Agricoltura) | Fumagalli, I. (Ente Nazionale per l'Energia Elettrica S.p.A. (ENEL), Cologno Monzese, Milan (Italy). Centro Ricerche Ambiente e Materiali)
Two tree species, hybrid Populus deltoides Bartr. Ex Marsh x Populus nigra L. (Populus x euramericana), clone I-214, and Robinia pseudoacacia L. were grown from clonal hardwood cuttings (clone I-214) and seedlings (R. pseudoacacia) for one growing season in either ambient (360 micronmol mol*[-1)) or elevated (560 micronmol mol*[-1)) CO2 concentrations in FACE (Free Air CO2 Enrichment) - system rings in the field. An equal number of plants in each FACE ring was subjected to two different watering regimes during summer, well watered and moderately stressed. Both clone I-214 and R. pseudoacacia exhibited a lower leaf conductance, higher photosynthesis at light saturation and ITE (istantantaneous transpiration efficiency) in CO2-enriched air. Clone I-214 was more responsive to elevated CO2 concentration, in terms of above-ground biomass and leaf area, than R. pseudoacacia. Species-specific responses to the watering regime were also observed, with more negative effects of the applied mild water stress on R. pseudoacacia. Clonal and species differences in response to elevated CO2 concentrations should be taken in account when planning future tree plantations in warmer and drier Mediterranean sites as foreseen by global circulation models
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