Elevated CO₂effects on stomatal density of wheat and sour orange trees

No significant differences were found in stomatal densities or stomatal indices of wheat or sour orange trees grown at high CO 2 concentrations in two different CO 2 enrichment systems (Free-Air CO 2 Enrichment for wheat and Open-Top Chambers for orange trees). These results are in accordance with most of the previous results obtained in short-term experimental studies which suggest that plants do not acclimate to increasing CO 2 concentration by changing stomatal density within a single generation