Survey of changes in lichen bioindicator, Lecanora mularis, in exposure to different concentrations of sulfur dioxide

Sulfur dioxide as one of the important gas pollutants, has an irreparable impact on plants, animals and objects; therefore this monitoring and control is important. Biological indicators as air pollutants indicators, are appropriate conductive in order to air pollution control in urban and industrial environments. Lichens are one of the bioindicators that are used in this case. Therefore, survey of efficiency and effectiveness biomonitoring of SO2 with use of lichen, Lecanora mularis, was considered. In this research, Lecanora was placed into the special bags and exposed with 40, 100 and 200 ppb SO2 for three hours. Then chlorophyll determination (chl a, chl b and chl a+b) and ratio of OD 435/415 was measured by extracting of 20 mg net weight of lichen in 10 ml DMSO. Thus, the average of chlorophyll determination (chl a, chl b) in control and exposed samples to SO2 was 94.1% and 77.3%, respectively; and there was a direct relationship between determination and pollutant's concentration, in all cases. So, in order to high sensivity of lichens to uptake the SO2, monitoring and indicating the existence and absence of sulfur dioxide in air is possible, thus this monitoring is one of the most effective and applicable approach.