Photosynthesis, chlorophyll integrity, and spectral reflectance in lichensexposed to air pollution

The major objective of the present study was to identify the relationship o f physiologial parameters of the photosynthetic system with the elemental c ontent of the lichen Ramalina lacera (With.) J.R. Laund. Thalli of R. lacer a were collected in an unpolluted site and transplanted in a national park and an industrial region in Israel for 8 mo. Analyses of photosynthetic act ivity, chlorophyll integrity, spectral reflectance, and amount of 11 metals were performed after this period of exposure. The normalized difference ve getation index (NDVI), indicative of the spectral reflectance response of t he thallus, correlated with photosynthetic rate and chlorophyll and K conte nt and correlated inversely with amounts of Ba, Cr, Cu, and Ni. The NDVI ap pears to enable the detection of early signs of pollutant-induced stress be fore changes in other physiological parameters become apparent. Elevated am ounts of Cr, Cu, Fe, h Zn, Ni, and Zn in lichens transplanted to an industr ial area and the correlation of Mn and Ni, Mn and V, Ni and V, Fe and Mn, F e and V, and Fe and Zn point for the greater part to metal processing in a steel smelter. Correlations of Cr and Ni, Cu and Ni, Zn and Cu, Cu and Mn, and Zn and Ni could be related to metal processing in the industrial area b ut indicate also vehicular activity as a possible originator.