Foliar Fatty Acids and Sterols of Soybean Field Fumigated with SO2

Abstract

Soybean plants, 60 days old, were exposed in the field to 78.7 pphm [parts per one-hundred million] SO2 in an open-air fumigation system for 20 days. Leaves from the top 1/4 and bottom 1/4 of the plants were analyzed for chlorophyll, free fatty acids, fatty acid esters, polar lipid fatty acids and sterols. Fumigated plants had a lower chlorophyll, free fatty acid and polar lipid content, but a higher fatty acid ester content. Of the individual fatty acids, linoleic and linolenic acid increased with SO2 fumigation while palmitic acid decreased. SO2 fumigations had only a minor effect on leaf sterols. The lower, more mature leaves showed a greater response to SO2 exposure.