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Journal of Environmental Quality Abstract -

Physiological Effects of the Mexico City Atmosphere on Lichen Transplants on Oaks


This article in JEQ

  1. Vol. 28 No. 5, p. 1548-1555
    Received: Sept 17, 1998

    * Corresponding author(s): tom.nash@asu.edu
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  1. A. Zambrano,
  2. T. H. Nash III * and
  3. C. Gries
  1. Department of Plant Biology, Arizona State Univ., Tempe, AZ 85287-1601.



Two lichen species, Usnea ceratina Ach. and Everniastrum neocirrhatum (Hale M. Wirth) Hale ex Sipman, were transplanted for 54 d into an oak forest (Quercus rugosa) in the vicinity of Mexico City to assess their ability to survive near a highly polluted urban environment. Net photosynthesis based on dry weight and chlorophyll b decreased respectively ca. 30 and 25% compared with control samples in a less polluted site, ca. 100 km north of Mexico City. There was no interspecific difference in the response of carbon fixation, but E. neocirrhatum was more sensitive to chlorophyll b degradation near Mexico City than U. ceratina. Chlorophyll a was also degradated (ca. 15%) near Mexico City. Changes in total carotenes were mostly dependent on species and time rather than on location. High concurrent levels of ozone and sulfur dioxide in the air are discussed as possible causes of the decline in the lichen photosynthesis and chlorophyll content.

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