Tropospheric ozone (O3) is the most important air pollutant because of its effects on forests and relationships with climate change. Results obtained by IPP-CNR in recent years suggest Mediterranean forests are less O3 sensitive than they were thought before. This does not imply that Mediterranean forests are free of any O3 damage. Visible foliar injury, stomatal alterations (increased night-time transpiration, delayed closure in response to water and light variations), increased susceptibility to other stressors (drought, weak parasites) as well as background O3 levels exceeding European standards, confirm O3 pollution as a serious concern to Italian forests. To protect forests from O3 effects, Europe uses one only exposure index, i.e. AOT40, for the entire continent. Researchers now know that O3 exposure does not summarize the real potential of O3 injury to vegetation. A new concept of flux has been developing and includes avoidance through stomatal closure and tolerance through detoxification and damage repair. Validating the O3 flux approach implies a great deal of scientific effort. Meanwhile, different AOT40 thresholds on a geographic or plant-type basis may be tested.
L ozono ed i suoi effetti sulle foreste mediterranee.
PAOLETTI E
2007
Abstract
Tropospheric ozone (O3) is the most important air pollutant because of its effects on forests and relationships with climate change. Results obtained by IPP-CNR in recent years suggest Mediterranean forests are less O3 sensitive than they were thought before. This does not imply that Mediterranean forests are free of any O3 damage. Visible foliar injury, stomatal alterations (increased night-time transpiration, delayed closure in response to water and light variations), increased susceptibility to other stressors (drought, weak parasites) as well as background O3 levels exceeding European standards, confirm O3 pollution as a serious concern to Italian forests. To protect forests from O3 effects, Europe uses one only exposure index, i.e. AOT40, for the entire continent. Researchers now know that O3 exposure does not summarize the real potential of O3 injury to vegetation. A new concept of flux has been developing and includes avoidance through stomatal closure and tolerance through detoxification and damage repair. Validating the O3 flux approach implies a great deal of scientific effort. Meanwhile, different AOT40 thresholds on a geographic or plant-type basis may be tested.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
