ELEVATED CO2 EFFECTS ON STOMATAL DENSITY OF WHEAT AND SOUR ORANGE TREES

No significant differences were found in stomatal densities or stomata l indices of wheat or sour orange trees grown at high CO2 concentratio ns in two different CO2 enrichment systems (Free-Air CO2 enrichment fo r wheat and Open-Top Chambers for orange trees). These results are in accordance with most of the previous results obtained in short-term ex perimental studies which suggest that plants do not acclimate to incre asing CO2 concentration by changing stomatal density within a single g eneration.