Full text
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| Author(s): |
Cláudia Maria Furlan
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 1998-10-22 |
| Examining board members: |
Antonio Salatino;
Maria Ines Salgueiro Lima;
Marico Meguro
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| Advisor: | Antonio Salatino |
| Abstract | |
The vegetation of the Atlantic Forest on Serra do Mar near the industrial complex of Cubatão (state of São Paulo, Brazil) has been subject of severe damage caused by massive emissions of pollutants, as a result of the progressive industrialization in the area. The amounts of nitrogen, total soluble phenols, total tannins, fibers and lignins, as well as leaf area, leaf area damage by herbivory and percentage of galls, were measured for leaves of Tibouchina pulchra Cogn. (Melastomataceae), a species resistant to air pollution and widespread in the region. The purpose of the investigation was to evaluate the effects of air pollution on the content of some classes of secondary metabolites and the possible consequences on the intensity of foliar herbivory. Fully expanded leaves of five individuals were collected for analysis in January, February, June and July 1996 and 1997, at three sites of Cubatão and Serra do Mar, each area presenting distinct pollution loads: the Pilões Valley (RP), near to SABESP station, characterized by a virtually undamaged vegetation and taken as a reference area; the Caminho do Mar (CM), along the old road connecting the cities of São Paulo and Santos, influenced mainly by the pollution emitted by petrochemical industries at the foot of this road; Mogi Valley (VM), close to the core region of the industrial complex, influenced mainly by pollution emitted fertilizer and chemical industries, steel production and cement factories. Relative to Pilões Valley, the individuals growing in the Caminho do Mar and Mogi Valley areas presented higher amounts of foliar nitrogen (on average 19,86 mg/g RP, 23,16 mg/g CM and 25,14 mg/g VM), fibers (36% RP, 46% CM and 49% VM) and lignins (10% RP, 13% CM and 8% VM) and lower amounts of total soluble phenols (5% RP, 1,7% CM, and 2,2% VM) and tannins (0,84% RP, 0,26% CM and 0,5% VM). The total leaf area found was not significantly different from one area to another, but differences were observed relative to the areas consumed by herbivory: they were larger at Mogi Valley and Caminho do Mar than at Pilões Valley (0,4% RP, 0,9% CM and 3,5% VM). The percentage of galls was highest at Mogi Valley and lowest at Caminho do Mar, Pilões Valley presenting an intermediate value (4,25% RP, 1,25% CM and 8,42 VM). For all parameters measured, the differences between summer and winter were not significant. The results show that the air pollution released by the industrial complex of Cubatão affects the foliar content of nitrogen and secondary metabolites and that such alterations affect the intensity of herbivory. Regression analysis were carried out relative to the three selected areas of Cubatão, in order to look for an explanation for the leaf loss by herbivory. The model of regression selected the variable tannin content as the most important to explain the leaf area at Pilões Valley, 11% of the herbivory being accounted for by that parameter. In individuals from Pilões Valley, the intensity of foliar herbivory correlates negatively with tannin content. The lignins content accounts for 25% of the herbivory intensity at Caminho do Mar, a negative correlation between the latter parameter and lignins content being noticed. Approximately 8% of the herbivory intensity is accounted for by the content of total soluble phenols at Mogi Valley, again through a negative correlation. The regression coefficients found were significant, notwithstanding their small values. The results suggest that other factors, not investigated in the present work, also influence the intensity of foliar herbivory. (AU) | |