Abstract: A difference in oxidative stress existed in peel tissuewhen fruits were covered with plastic film or doublelayerpaper bags because they created distinct microenvironments. Influenced strongly by 'greenhouse effect' with plasticf ilm bags, fruits had a higher surface temperatures and the microenvironment was significant ly different from the outside,showing higher O₂and MDA contents during fruit enclosure and soon after bag removal.However, double- layer paperbags seemed to be favorable to rendering fruit with more ant ioxidative capability as a result of cross adaptat ion, exhibitingnot only lower levels of O₂and MDA contents during fruit enclosure and after bag removal, but a quick response of antioxidativeenzyme( SOD) to scavenge activated oxygen species. On a whole, enclosed fruits became more sensitive to thenew environment soon after bag removal, so that an abrupt increase of O₂contents or SOD act ivity occurred in fruits. Inorder to prevent fruits from physiological disorders, plastic film bags should not be applied on the periphery of southwestcanopy, and appropriate timing for bag removal has to be carefully considered.

Key words: Fruit bags, Bagging, Apple, Fruit, Oxidative stress

CLC Number: 

• S661.1