Details

Autor(en) / Beteiligte

• Zambrano, A.
• Nash, T. H.
• Gries, C.

Titel

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

Ist Teil von

• Journal of environmental quality, 1999-09, Vol.28 (5), p.1548-1555

Ort / Verlag

Madison, WI: American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America

Erscheinungsjahr

1999

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• 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.