Abstract:Two cultivars of nectarine, nonmelting-flesh 'Arm King' and melting-flesh 'Qinguang1, were used to investigate the enzyme activities in relation to fruit softening after harvest. Invertase and amylase activities were high during the rapid loss stage of fruit firmness, then decreased gradually during further softening. However, cellulase and polygalacturonase showed low activities, but increased significantly at climacteric stage. The activity of pectin methylesterase was low and showed little change. The activity of pectin methylesterase was low and showed little change.Activities of all these enzymes were higher in‘Oinguang’than in ‘Arm King’.