Immunofluorescent localization of urease in the cotyledons of jack bean, Canavalia ensiformis

Urease has been localized in sections of cotyledons from germinating seeds of jack bean, using FITC-labelled immunoglobulin prepared from urease antiserum raised in rabbits. The complication of lectin binding to the immunoglobulins was resolved by treatment of the sections with specific glycosides. Urease is localized in 2 sites: within the cytoplasm of storage parenchyma cells in spherical granules up to 3 micrometer in diameter, and within the intercellular spaces in spherical granules. Although similar in size, the latter are distinguished from the cytoplasmic granules by the presence of beta-lectin and appear to function as an extracellular lytic compartment or lysosome.