Soil drench of ethylenediurea (EDU) protects sensitive trees from ozone injury

Ozone (O-3) is the air pollutant of major concern for vegetation. Levels in Mediterranean cities may exceed the criteria for vegetation protection. Ozone may induce a number of plant responses, e.g., visible injury on the leaves, that affect the ornamental value of urban forests. Antioxidant application may protect sensitive plants from ozone. The most successful synthetic antioxidant is ethylenediurea (EDU). Here we set the optimal EDU dose and concentration (260 mg m(-2) leaf, 450 ppm) for protecting adult Fraxinus excelsior trees from ozone visible injury by means of EDU applications as soil drench.