Sulfur Concentrations in Plant Foliage and Related Effects

Abstract

Sulfur is an essential element for plants and is normally taken up from soil in the sulfate form. SO/sub 2/ absorbed from the air also can supply S for plant nutrition. Plants are therefore dependent on an optimum S content, but deficiencies or excesses can result in deleterious effects. Numerous assessment surveys were conducted in rural, urban, or industrial locations in Ontario to determine the concentrations of S in plants and related effects. During the ten year period, 1968 to 1977, about 50,000 samples of vegetation and soil were collected and analyzed for S concentrations. The results of these analyses were examined with respect to natural background concentrations of S in foilage of 33 different spcies, and effects observed on plant life associated with excess concentrations of S. For example, in one situation 0.35% sulfur in foilage of trembling aspen trees was found to be the threshold level for injury to occur. Some of the industries surveyed for the degree and extent of S effects in their vicinity included pulp mills, power plants, iron concentrators, and gold, nickel, and copper smelters. In interpreting the results of S analyses in plant foilage for diagnostic purposes, consideration should be given also tomore » the geographical location, the stage of growth of the plant, the relation of visible injuries to pollutant or biological causes, the S content of the soil, and SO/sub 2/ emission data for the area.« less