Cell wall autolytic activities and distribution of cell wall glucanases in Zea mays L. seedlings

Exo- and endo-glucanases mediate specific degradation of cell wall (1,3)(1,4)-beta-D-glucans and these enzymes have been related to auxin-mediated growth and development of cereal coleoptiles. However, their distribution and functions have not been well established in other tissues. In this study the glucanase activities and cell wall autolytic activities of different maize organs were determined. Autolysis assays serve to evaluate the hydrolysis of cell wall polymers in situ by measuring the sugars released from the insoluble cell wall matrix resulting from the action of bound enzymes. Autolytic activities were observed in the cell walls of elongating young leaves, mesocotyl and roots of maize. Wall proteins extracted from all of these structures are enriched in several types of glucanases and other wall polysaccharide hydrolases. These enzymes therefore appear to have a widespread and fundamental role in wall metabolism in growing tissues.