Plant Responses to Ozone Stress: Actions and Adaptations

Ozone (O3) is a blue-colored gaseous molecule naturally present in the Earth’s stratosphere region at about 20-30 km above the Earth’s surface. O3 was naturally formed in the stratosphere about 200 billion years ago by photolysis of molecular oxygen by UV radiations from the Sun and chemical recombination with oxygen molecules. O3 sensitivity is often linked to low leaf mass per area and low leaf area-based antioxidant levels or stomatal conductance. The damaging effects of O3 on plant health were reported as early as 1905 when there was severe vegetable crop damage in Los Angeles. The entry of O3 into the leaf through the stomata triggers a cellular response and ultimately results in damage to crop productivity. O3-induced oxidative stress often leads to general redox-dependent alterations in ion conductance in many plant species. Under natural conditions, plants constitute a significant part of the ecosystem. Practically any change in a plant can have a great impact on associated ecosystems