关键词: 梨(45NL49EU), 多酚氧化酶(45EC), 总酚, 组织培养(49DE)

Abstract: The regulation of polyphenoloxidase activities (PPO) and phenol contents of five pear varieties during March to September were studied.The results were following.The PPO activities of Yali (Pyrus bretshneideri Rehd), Pingguoli (P. sinkiangensis Yu) and Nanguoli (P. ussuriensis Maxim) buds and stem terminals during March to September showed double-peak curve and their peak values were in May, April and May individually.The PPO activities of Cangxili (P. pyrifolia Nakai) and Rimianhong (P. communis L.) showed single-peak curves and their peak values were in June and August individually The arrange ment of the PPO activities, peak values were:Nanguoli's > Yali's > Rimianhong's > Pingguoli's > Cangxili's.The phenol contents of the five pear varieties in September were highest and those in March were lowest during March to September.Cangxili's phenol contents in March.April, June and August were lowest in the five pear varieties when compared in the same month.In May.July and Septemher, the phenol contents of Rimianhong were lowest in the five varieties.

Key words: PEAR, POLYPHENOLYOXIDASES, PHENOL CONTENTS, MERICLONING