Impact of elevated CO2 on physiology and needle morphology of Scots pine (Pinus sylvestris) seedlings

The main objective of this study was to examine the impact of elevated atmospheric CO2 on leaf morphology, biochemistry and physiology of three year-old Scots pine (Pinus sylvestris L.) seedlings. Experimental facilities included four open top chambers (OTC), representing two replicated CO2 treatments, ambient (ca. 350 mu mol mol(-1), the current background level) and elevated CO2 (ambient + 350 mu mol mol(-1)). Trees outside the OTC were considered the control plot. Scots pine seedlings grown in elevated CO2 for one growing season exhibited a positive response to elevated CO2 conditions in this study, showing higher photosynthetic rates, higher chlorophyll, nitrogen and carbon concentrations, an unchanged C/N ratio, increased needle and dry mass per unit leaf area. Leaf nitrogen concentrations increased when expressed on an area basis, but not when on a mass basis.