SHORT-TERM AND CHRONIC EFFECTS OF COPPER, ZINC AND MERCURY ON THE CHLOROPHYLL CONTENT OF FOUR LICHEN PHOTOBIONTS AND RELATED ALGA.
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Accession number;04A0099894
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| Title;SHORT-TERM AND CHRONIC EFFECTS OF COPPER, ZINC AND MERCURY ON THE CHLOROPHYLL CONTENT OF FOUR LICHEN PHOTOBIONTS AND RELATED ALGA. |
| Author;
BACKOR M
(Univ. Western Ontario, Ontario, Can)
DZUBAJ A
(Safarik Univ., Kosice, Svk)
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Journal Title;J Hattori Bot Lab
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Journal Code:Y0255A
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ISSN:0073-0912
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VOL.;NO.95;PAGE.271-284(2004)
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| Figure&Table&Reference;TBL.9, REF.24 |
| Pub. Country;Japan |
| Language;English |
| Abstract;Chlorophyll a, chlorophyll b and chlorophyll a+b concentrations, as well as chlorophyll a/b ratios and assessment of chlorophyll a integrity (OD 435/OD 415, OD 665/OD 665 after acidification) were determined in order to compare the short-term effects of copper, zinc and mercury on four lichen photobionts (Trebouxia erici, T. irregularis, Myrmecia biatorellae, Coccomyxa sp.) and the related alga Leptosira terrestris. Chlorophyll a was sensitive to presence of copper and mercury, but less to zinc. Chlorophyll b increased in response to copper exposure, as in the case of zinc, but the effect was less pronounced, resulting in a significant decrease of the chlorophyll a/b ratio, while the total chlorophyll content was almost unchanged. Mercury, on other hand, caused a decrease in both chlorophyll a and chlorophyll b, and total chlorophyll content was a useful parameter for assessment of metal stress. Differences between metals and between tested concentrations were more pronounced than differences due to taxa. When the photobiont T. erici was cultivated on media with metal supplements, long-term exposure to metals decreased growth of cultures. We observed a complex influence of metals on chlorophyll in two wk old cultures. Chlorophyll a was more sensitive to metals than chlorophyll b, and its decrease was attributable to conversion of chlorophyll a to chlorophyll b by copper and zinc, inhibition of chlorophyll synthesis by mercury, and even 3 mM zinc, as well as by increased phaeophytinisation. (author abst.) |
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