Comparative growth in elevated CO2 environments

Effects of long-term CO2 enrichment on Sitka spruce (Picea sitchensis (Bong.) Carr) and cherry (Prunus Avium L.) plants were examined. Both species were grown in open top chambers with elevated (ambient + similar to 350 mu mol mol(-1)) or ambient (similar to 350 mu mol mol(-1)) CO2 concentrations. Cheery seedlings showed an increased WUE under elevated CO2 at both leaf and plant scale. All Sitka spruce and cherry plants were in exponential growth phase (although departing from initial exponentiality) throughout the experiments. Both species showed a positive growth response to CO2 enrichment. The difference in total biomass at the end of the experiment was a consequence of the more rapid initial growth of the elevated CO2 plants. As a result the relative growth rate in elevated CO2 exceeded that in ambient CO2 only during the first interval of growth, and were equal and unchanged for the rest of the experimental period. This finding may be particularly important for greenhouse crop production.