Ozone (O3) is one of the major atmospheric pollutants in the Mediterranean area and negatively interacts with several biochemical and physiological processes of the plants. Olive is one of the most widely cultivated trees in the Mediterranean climates and previous studies have shown that O3 can potentially interfere with olive trees productivity. In order to test the physiological and biochemical changes induced by realistic O3 levels (100 and 50 ppb, 5 h-1 day) in newly developed olive leaves, the effects of long term (18 months) O3 exposure were investigated on Moraiolo and Frantoio cultivars. Data on gas exchange showed that O3 treatment had significant effects on photosynthetic activity and stomatal conductance with some differences between the two cultivars. X-ray spectra obtained from guard cells of open and closed stomata confirmed the main role of K to establish the differences in the ionic state between open and closed stomata. Moreover, O3 exposure induced a decrease in K and Ca net counts with respect to the control treatment suggesting the development of an adaptive mechanism to O3 which controls stomata responses at reduced ionic levels. Biochemical assays showed that ascorbate peroxidase activity was not affected by O3 treatments in Frantoio, while it increased in Moraiolo plants exposed to 50 ppb of O3.
Physiological and biochemical reactions of olive genotypes during site-relevant ozone exposure
LORENZINI, GIACOMO
2002-01-01
Abstract
Ozone (O3) is one of the major atmospheric pollutants in the Mediterranean area and negatively interacts with several biochemical and physiological processes of the plants. Olive is one of the most widely cultivated trees in the Mediterranean climates and previous studies have shown that O3 can potentially interfere with olive trees productivity. In order to test the physiological and biochemical changes induced by realistic O3 levels (100 and 50 ppb, 5 h-1 day) in newly developed olive leaves, the effects of long term (18 months) O3 exposure were investigated on Moraiolo and Frantoio cultivars. Data on gas exchange showed that O3 treatment had significant effects on photosynthetic activity and stomatal conductance with some differences between the two cultivars. X-ray spectra obtained from guard cells of open and closed stomata confirmed the main role of K to establish the differences in the ionic state between open and closed stomata. Moreover, O3 exposure induced a decrease in K and Ca net counts with respect to the control treatment suggesting the development of an adaptive mechanism to O3 which controls stomata responses at reduced ionic levels. Biochemical assays showed that ascorbate peroxidase activity was not affected by O3 treatments in Frantoio, while it increased in Moraiolo plants exposed to 50 ppb of O3.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
