Protease formation in Phaseolus vulgaris L. cotyledons during seed germination was studied histochemically using a gelatin-film-substrate method. Protease activity can be detected by this method on the 5th day of germination, at approximately the same time that a rapid increase of activity was observed by a test-tube assay with casein as a substrate. At the early stage of germination, protease activity was observed throughout the cotyledon except in two or three cell layers below the cotyledon surface and in several cell layers around the vascular bundles. A highly active cell layer surrounding the protease-inactive cells near the vascular bundles is suggested to be a source of the protease.

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The leaf roll-necrosis disorder has been identified in collections of lilac (Syringa vulgaris L.) in or near the cities of New York, Philadelphia, and Boston. Observed symptom differences among lilacs at 6 sites were largely quantitative, indicating the occurrence of incitants common to all locations. Activated charcoal and 4,4’-dioctyldiphenylamine filter chambers applied to branches reduced injury and provided corroborating evidence that air pollutants, including oxidant-type, were causal factors. Monitoring data from New York City and Philadelphia revealed progressively decreasing pollutant levels in recent years that coincided with decreases in severity of the disorder. Fluoride was not a causal agent, based on low levels in leaves. In experimental fumigations of lilac clones, although the results were inconclusive regarding identification of causal pollutants, ozone and sulfur dioxide induced some symptoms of the disorder. The occurrence of additional field symptoms suggested the involvement of other, as yet unidentified, phytotoxic pollutants.