| In this paper, with the nectarine variety'QinGuang-2hao'as meterial, a series of changes in fruits were investigated under chilling injury temperature, which included physiology effect, respiration and ethylene metabolism related enzymes, activated oxygen scavenging enzymes and LOX activities of nectarines, concurrently the content of PAs, fatty acid and internal secretion were determined .The result showed as follows:1. The film packaging had some advantage effect on reducing the chilling injury of nectarine fruits. The temperature of chilling injury were 3℃, 5℃and 7℃, respectively 5℃treatment was the most sensitive one, 3℃was the next, then 7℃. When put in 1℃, the fruits could be stored for 40d, and they could keep good commodity quality. 8℃, 11℃were suitable for short-term storage. The main chilling injury symptoms were water-damaged spots appearing on the part of fruits surface. Moreover, with the development of chilling injury, the symptoms expanded to the fruit interior, accompanying the browning in peel and flesh and losing its flavor. In addition, there also had woolliness and breakdown in a small quantity of fruits.2. Under the chilling injury temperature, some unusual changes were taken place, including respiration rate, ethylene production, the relative membrane penetrability and fruit firmness. Firstly, the respiration rate and ethylene production increased greatly, and then they decreased suddenly. The relative membrane penetrability sharply enhanced after 10 days cold storage, and continuously increased afterwards. The firmness reduced untill stored for 30 days, then gradually increased. Therefore, these unnormal changes could be regarded as the main indexes for chilling injury. In addition, the 20th day was the turning point of irreversible injury for nectarines.3. In the early stage, COX controlled respiration during the process of low temperature injury. PPO regulated respiration metabolism possibly in the time of middle and later period. The substance which ethylene synthesis influenced by chilling injury was the effect of chilling injury to ACO activity. In low temperature injury, ethylene biosynthesis conformed to the normal synthesis way, and ACO maybe the limited speed enzyme. There had a certain limitation between LOX activity and ethylene biosynthesis. LOX influenced ethylene synthesis by the way of impacting the process of transforming SAM to ACC. LOX activity had intimate relationship to membrane lipid peroxidation.4. The activities of SOD, CAT and POD changed abnormally when chilling injury happened. APX activities reduced and MDA accumulated massivly. Compared to the treated fruits, the control had lower activities in SOD, CAT and POD, however, they were relatively stable. So it was benefit for balance between activated oxygen and the defense system, and it was advantageous to maintain low metabolism and reduce the cell storing matter consumption as well.In nectarine fruits, the main saturated fatty acid included palmitinic acid and stearic acid, whereas the main unsaturated acid were oleic acid, linoleic acid and linolenic acid. Under the chilling injury temperature, the content of palmitinic acid, stearic acid, Oleic acid, linoleic acid and total fatty acid, IUFA decreased gradually. There had intimate relationship among Oleic acid, linoleic acid, total fatty acid, IUFA and chilling injury.5. Chilling injury was related to the massive accumulation of Put and the reduction of Spd and Spm of nectarines. In the process of cold storage, the accumulation level of Put and chilling injury index appeared extremely remarkable positive correlation, r=0.9862. The content of Spm and Spd were also relevant to CII, the order about correlation degree of Spm(-0.9470)was higher than that of Spd(-0.9201).There was not obvious correlation between the Cad content and the CII.Before the serious electrolyte leaking, the content of ABA and ZR increased. When the damage was irreversible, the content of ABA and ZR decreased. During the storage period, the GA and IAA content of chilling injury fruit lessened .
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