The study assessed the effect of cumulative tropospheric ozone on the morphology of an ozone-sensitive (Bel W3) and an ozone-resistant (Bel B) tobacco cultivar, and two petunia cultivars (Mirage, White Cascade). The plants were exposed at two sites differing in tropospheric ozone level for two months during the 2008 growing season. Similar sets of plants were cultivated in control conditions. Morphological parameters of the plants were measured every week during the experiment. The correlation between the recorded results and the cumulative concentrations of tropospheric ozone measured at the two exposure sites was estimated. The ozone-sensitive tobacco cultivar showed increased visible damage after four weeks of the experiment, although ozone was relatively low during the preceding weeks, possibly confirming the cumulative effect of ozone on the plant response. The ozone-resistant tobacco cultivar showed higher mean plant growth and leaf growth than the ozone-sensitive one throughout the experimental period, but at the exposure sites the ozone-sensitive cultivar showed plant growth similar to or higher than the controls, especially at the forest site where ozone concentrations were higher. This suggests a plant defense against reduction of leaf assimilation area (i.e., against leaf necrosis). Petunia cv. Mirage showed lower growth at the control site and had fewer flowers than White Cascade at all sites. White Cascade had more flowers than Mirage in the last week of the experiment at the forest site where tropospheric ozone was higher. Its mean growth was higher at the forest site than at the other exposure site
Tropospheric ozone is one of the most reactive air pollutants, which causes visible injuries, as well as biomass and yield losses. The negative effect of ozone is cumulative during the growing season; hence crops are the most sensitive plants. Visible symptoms and biomass losses can cause economic losses. Tobacco plants have been recognized as one of the best bioindicators, but data on the cumulative effect of ozone on this species are limited. Results of an experiment with ozone-sensitive tobacco plants grown on sites varying in ozone concentration are presented in this paper. Two indices were used for data presentation of visible leaf injury degree. Higher solar radiation was the main cause of higher ozone concentration at the rural site. Higher tropospheric ozone concentrations were noted in 2010 in comparison to 2011, which was reflected in visible leaf injury. Canonical variate analysis did not reveal highly significant differences between sites, however, differences were observed in certain investigation periods. Moreover, higher leaf injury was noted at the rural site at the end of the experiment in both experimental years. This indicates the cumulative effect of ozone during the growing season. However, higher injury variability was noted at the urban site, even though lower ozone concentrations were noted there. Lower variability of injury at the rural site might suggest lack of influence of particulate matter and occurrence of higher injury even though lower ozone concentrations occurred. Better detection of ozone injury was shown by the first index based on three mean values.
The paper addresses the effect of a compost prepared from tobacco wastes with an admixture of bark and straw on the enzymatic activity and certain chemical properties of a grey-brown podzolic soil amended with that compost. The study was conducted under the conditions of a pot experiment in which the soil material was collected from the surface horizon of the grey-brown podzolic soil. The effect of the application of the compost was compared with soil without such amendment. The test plant was maize cv. Kosmo 230. Fertilisation of the light soil with the compost studied caused changes in the enzymatic activity of the soil that were related both to the dose of the compost and to the kind of enzyme studied. With increase in the dose of the compost there was an increase in dehydrogenase activity (highest dose) and a signiﬁcant decrease in the activity of acid phosphatase. Moreover, it was observed that tobacco compost was a signiﬁcant source that enriched the light soil in organic matter, total nitrogen, and available forms of phosphorus, magnesium and potassium, which was evident in increased yields of maize grown as the test plant. Signiﬁcant correlations were also demonstrated between a majority of the biochemical and chemical parameters, which indicates that those parameters characterise well the biological properties of a grey-brown podzolic soil amended with tobacco compost.