Szukana fraza: [Abstract = The chlorophyll b\/a ratio revealed an opposite position to ozone concentration only in the ozone\-resistant tobacco cultivar. In all the plant species the highest average chlorophyll content was noted after the 7th day of the experiment. Afterwards, the plants usually revealed various responses. Ozone\-sensitive tobacco revealed decrease of chlorophyll content, and after few weeks of decline again an increase was observed. Probably, due to the accommodation for the stress factor.]