Abstract: Activities of pectolytic enzymes and cellulase in peaches 〔Prunus persica (L. )
Batsch cv. Baifeng〕were determined during softening and development of woolly breakdown. Enzy-matic response to pre-warming and intermittent warming was also analyzed. Start of fruit softening seemed to be connected with the activity increase in PE , PGand cellulase. However , the level of PE
and PG activities was not significantly related with the fruit firmness. Both endo2PGand cellulase activities were significantly negative correlated with the degree of woolly breakdown ( r = - 0. 9408 , r =- 0. 9234) . The essential aspect of chilling injury known as woolly breakdown induced by low temperature stress was the abnormal degradation of cell wall pectin , which was not only controlled directly by pectolytic enzymes but also influenced largely by cellulase. Alleviating chilling injury with the treatment of pre-warming or intermittent warming was responsible for the prevention from irreversible
damage to endo-PGand cellulase from low temperature stress and thus guaranteeing the normal process of pectin degradation.

Key words: Peach 〔Prunus persica (L. ) Batsch〕, Woolly breakdown, Polygalacturonase, Pectinesterase, Cellulase