Spectral characteristics of lichens affected by air pollution



Lichens are sensitive in varying degrees to man-induced pollutants such as sulphur dioxide. This fact is widely used as an indicator of air quality.

Several studies, led by Prof. Yaacov Garty from Tel Aviv University, were designed to determine the environmental impact of pollutants emitted by combustion of heavy fuel oil in Ashdod and Haifa vicinities, in Israel. For this purpose, thalli of Ramalina duriaei lichen (in the picture) were transplanted from a clean environment to the suspected polluted one.

At the end of each experiment the photosynthetic activity, chlorophyll integrity, electric conductivity, spectral reflectance, as well as chemical content of different elements of the thalli were analyzed. It was found that the normalized difference vegetation index (NDVI), indicative of the spectral reflectance response of the thallus, correlated with photosynthetic rate, chlorophyll, K, and P content, and inversely correlated with amounts of Al, Ba, Cr, Cu, Fe, Ni, Pb, Pe, Sulfat-S, V, and Zn. The results are summarized in the following table. The NDVI appears to enable the detection of early signs of pollutant induced stress before changes in other physiological parameters become apparent.
From:Mar. 93Mar. 93Feb. 94Nov. 94Apr. 97Apr. 98
To:Jun. 93Jan. 94Nov. 94Aug. 95Nov. 97Nov. 98
Duration:3 months10 months9 months9 months7 months7 months
Significance levels:
*P<=0.05 **P<=0.01 ***P<=0.005 ****P<=0.001




Garty, J., Weissman, L., Cohen, Y., Karnieli, A. and Orlovsky, L. 2001. Transplanted lichens in and around the Mount Carmel National Park and the Haifa Bay industrial region in Israel: Physiological and chemical responses. Environmental Research, 85, 159-176.

Garty, J., Tamir, O., Hassid, I., Eshel, A., Cohen, Y., Karnieli, A., Orlovsky, L. 2001. Photosynthesis, chlorophyll integrity, and spectral reflectance in lichens exposed to air pollution. Journal of Environmental Quality, 30, 884-893.

Garty, J., Weissman, L., Tamir, O., Beer, S., Cohen, Y., Karnieli, A. and Orlovsky, L. 2000. Comparison of five physiological parameters to assess the vitality of the lichen Ramalina lacera exposed to air pollution. Physiologica Plantarum, 109, 410-418.

Garti, J., Cohen, Y., Kloog, N. and Karnieli, A. 1997. Effects of air pollution on of cell membrane integrity, spectral reflectance and metals and sulfur concentration in lichens. Environmental Toxicology and Chemistry, 16, 1396-1402.

Garti, J., Karnieli, A., Wolfson, R., Kunin, P., and Garty-Spitz, R. 1997. Spectral reflectance and integrity of cell membranes and chlorophyll relative to the concentration of airborne mineral elements in a lichen. Physiologia Plantarum, 101, 254-264.

Garti, J., Kloog, N., Cohen, Y., Wolfson, R. and Karnieli, A. 1997. The effect of air pollution on the integrity of the chlorophyll, on the spectral reflectance response and on the concentration of airborne Nickel, Vanadium and Sulfur in the Lichen Ramalina duriaei (De Not.) Bagl. Environmental Research, 74, 174-187.

Garti, J., Kloog, N., Wolfson, R., Cohen, Y., Karnieli, A. and Avni, A. 1997. The influence of air pollution on the concentration of mineral elements, on the spectral reflectance response and on the production of stress-ethylene in the lichen Ramalina duriaei, The New Phytologist, 137, 587-597.