APPLICATION OF A MULTIDIMENSIONAL LINEAR MODEL TO COMPARE DEGREES OF TOBACCO LEAF INJURY CAUSED BY TROPOSPHERIC OZONE AT RURAL AND URBAN EXPOSURE SITES

摘要

Tropospheric ozone is one of the most phytotoxic air pollutants. Its concentration has doubled over the last few decades. Ozone may cause visible injuries on plants and biomass losses, which is especially dangerous for crop plants. Bioindicator plants are used for detecting the occurrence of ozone at phytotoxic levels. Tobacco plants reveal visible injuries due to the elevated ozone concentrations in the ambient air. Two tobacco cultivars were used in the study presented here - one sensitive and one resistant to tropospheric ozone. The experiment was performed at two exposure sites - urban and rural - in the city of Poznan and in the surrounding area (Tarnowo Podgorne). Plants were exposed for two-week series in 2003-2006, from mid June until early September. Multi-variate analysis using a variance model and dual canonical variate analysis were used for interpretation and graphical presentation of air bioindication results. The degree of tobacco leaf injury caused by ozone was higher at the rural site, which is attributable to the transportation of ozone precursors and the formation of ozone at large distances from its precursors' sources. Moreover, differences between years were recorded, due to the variability of meteorological conditions occurring during those years, which either favor or hinder tropospheric ozone creation.