Assessment of The Effects of Sulfur Dioxide (SO2) on Lichens Using Energy Dispersive X-Ray Spectroscopy

Abstract

Lichens which are ubiquitous plants composed of a symbiont fungus and alga have been known for years to be sensitive bioindicators of air pollutants. Their presence has been used as an index of atmospheric purity. It is thought that sulfur dioxide (SO2) is the prime cause for the disappearance of lichens from urban areas (a lichen desert). Air quality can be monitored by observing the deterioration of lichen flora by their ability to absorb pollutants efficiently. Although certain pollutant-sensitive species do not readily demonstrate macroscopic changes in early stress situations, monitoring of photosynthetic capabilities and chlorophyll content have been used as a measure of subtle metabolic changes. Concomitant with a reduction in photosynthesis, an intracellular loss of potassium (K+) has been noted.