A bstract. Soybean, Glycine max L., and elodea, Elodea canadensis Michx, leaves were exposed to sublethal and lethal temperatures and examined by light microscopy. Loss

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Using maceration, viscometric, and spectrophotometric tests, culture filtrates and extracts of healthy and Helminthosporium sativum-infected common and Merion Kentucky bluegrass foliage were tested for pectolytic and cellulolytic enzymes. Culture filtrates, in which pectin was the carbon source, exhibited polymethylgalacturonase and pectin methyl-trans-eliminase activity, with optima of pH 6–7 and pH 8, respectively. Extracts from diseased foliage of common and Merion Kentucky bluegrasses contained pectin methylesterase, optimum activity at pH 7; trans-eliminase, most active at pH 8–9.5; and cellulase (Cx), most active at pH 6. These enzyme activities were always higher in diseased Merion than common Kentucky foliage. Enzyme preparations of diseased common bluegrass also produced polygalacturonase, optimum activity at pH 6, while diseased Merion extracts produced polymethylgalacturonase, with maximum activity at pH 6. Partial purification of the trans-eliminase enzymes indicated they were endopolygalacturonate-trans-eliminases. Extracts of healthy foliage of both varieties contained high pectin methylesterase and low cellulase (Cx) activity.