Foliar sterols in soybeans exposed to chronic levels of ozone.

Soybeans (Glycine max) exposed to chronic levels of ozone showed a linear decrease in biomass with increasing concentration. The foliar free sterols increased while the steryl ester, and the steryl glycosides, a minor component, decreased with increasing pollutant concentration. Of the free sterols, stigmasterol showed the largest increase, followed by sitosterol; campesterol, however, decreased. All steryl esters decreased; sitosterol showed the largest decrease and campesterol the least.