The Enzymes Associated with Leaf Abscission in Cotton

Abstract

The enzymes cellulase and pectinase were examined during ethylene induced leaf abscission in cotton (TAMCOT CAMD-E). Pectinase proved unassayable due to an enzymatic factor that jelled the assay mixture. Cellulase was assayed and the abscission zone was found to have the greatest levels of cellulase, even though it existed throughout the plant. Extraction of the cellulase required high NaCl concentrations in the buffer solution, thereby indicating that the cellulase extracted was 9.5 pI cellulase, the form active in abscission. Further localization studies found the cellulase levels were slightly higher on the proximal side of the abscission zone. A time course comparing per cent leaf abscission and cellulase levels with time in ethylene showed that per cent leaf abscission rose, but cellulase did not. Large amounts of PVP had to be added to the extract preparation.