Effect Of Exogenous Putrescine On Chilling Injury,Quality And Physiology During Storage Of Nectarine

In order to study the effects of exogenous putrescine (Put) treatment on chilling injury of nectarine fruits during cold storage (0±0.5℃) . With the nectarine variety'Qinguang 2'as tested material, non-treatment as ck. The effects on improving the cold tolerance,decreasing the chilling injury rate and keeping fruits quality were studied in this paper. Concurrently the content of endogenous polyamines, respiration rate, ethylene production, activated oxygen scavenging enzymes and LOX activities and the activities of amylase correlated cell wall substance (cellulose pectin). The result showed as follows:1. Compared with the effect of Put treatment of different concentrations (1 mmol/L,3 mmol/L,10 mmol/L,15 mmol/L), the effect of 10 mmol/L treatment was the best.2. Under cold storage, Put treatment induced cold tolerance in nectarine fruits, the chilling injury was delayed for 10 days by exogenous Put (10mmoL/L) treatment, the chilling injury rate and chilling injury index were different from ck. Compared with the ck, the chilling injury rate and chilling injury index of Put decreased 30.0%and 18.3% after 50 days storage. The contents of endogenous Put level increased during cold storage and reached a peak value after 45 days, spermidine (Spd) and spermine (Spm) level increased continuously, Put treatment raised the endogenous polyamines content of nectarine fruits. Delayed the chilling injury of nectarine fruits effectively.3. Put decreased the weight loss rate, made the content of total soluble solid (TSS) at a high level. At the same time the degradation rate of the flesh firmness,vitamin c (Vc) of nectarine fruits were reduced obviously. However, it showed no remarkable effect on the contents of titratable acidity (TA) and chlorophyll. So it was help to the fruits'favor and qualities.4. Put decreased the respiration rate, restrained the ethylene create and production of nectarines. Compared with ck, the peak of respiration rate and ethylene production delayed for 5 days.5. Put restrained the degradation of polygalacturonase (PG) and pectinmethylesterase (PE) activities, which put off the fruit softening process and maintained their flesh firmness of nectarine fruits. Meantime, Put significantly raised the activities of membrane superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) and inhibited the lipoxygenase (LOX) activity; the malondialdehyde (MDA) content and the increase in the relative membrane permeability were slowed down. so that Put enhanced the levels of free radical cleaning ,alleviated lipid peroxidation and maintained better cell membrane integrity, and reduced the occurrence of chilling injury.In comprehensive consideration, the Put treatment has remarkable effect on nectarine chilling injury during cold storage, which could delay the chilling injury rate and chilling injury index, keep quality and flavor of nectarine fruits preferably, suppressed the respiration rate and ethylene production, postpone the caducity of nectarine fruits in a certain. So that Put has a better prospect in the storage of fruit and vegetable.