| We found that heat treatment(48C,3h) can induce anti-chilling injury. In order to research the mechanism of HAT induction of anti-chilling injury in persimmon fruits, endogenous polyamines content, activated oxygen scavenging enzymes, LOX, fatty acid composition , cell wall hydrolase, cell wall composition and cell wall ultrastructure were investigated. Results are showed below:Persimmon fruits can store for 20-25 days and 35-45 days at 12C and 8C, respectively. If it is to be stored above 50 days, it must require a medium of 4C or below. Chilling injury symptoms and physiological disorders were observed when the fruits were transferred to normal temperature after storage at 4C for more than 20 days. As CI in persimmon is characterized by a brown-dark discoloration and pitting of the peel, the immature fruits cannot ripen normally,and fruit flesh lost flavor and even caused gelling of the flesh. Fruit juice had high viscosity and lower extractable juice rate. Respiration rate, ethylene production and permeability of persimmon fruits skin were abnormally high.Heat treatment reduced chilling sensitivity and alleviated physiological disorders. HAT at 48C for 3h or 44C for 4h were found to be most suitable foralleviating chilling injury in persimmon fruits. These two treatments retarded respiration rate, ethylene production and permeability of persimmon fruits skin. It also enhanced normal ripening and softening, reduced relative viscosity of fruit juice, improved extractable juice rate, but had little effect on TSS content. HT with too high temperature or too long exposure time caused heat injury. Persimmon fruits exposed to 52"C for 2h resulted in heat injury that was harmful to fruits.The extent of accumulation of spd, spm and put in persimmon correlated inversely with the occurrence chilling injury, Spd(-0.923) > Spm(-0.904) > Put(-0.781), respectively. Cad content did not correlate with chilling injury. HAT(48C,3h) increased endogenous polyamine(spd, spm, put and cad) contents, and reduced the occurrence of chilling injury. It has been suggested that these polyamines may protect plants from CI by a mechanism that involves protecting membrane lipids from peroxidation.The activities of SOD, CAT, APX and GR decrease during storage of persimmon, but the activities of LOX increased. HAT(48C,3h) retarded decrease in the activities of CAT, APX, GR and inhibited LOX from increasing.During cold storage of persimmon fruits there was very little change in fatty acid fraction, when returned to 20 C to ripen, the content of palmitic acid, stearic acid and oleic acid increased, while the content of linoleic acid, linolenic acid and total unsaturated fatty acid and IUFA decreased, giving rise to chilling injury syptoms. HAT(48C,3h) retarded decreases in the content of linoleic acid, linolenic acid, total unsaturated fatty acid and IUFA, especially linolenic acid and total unsaturated fatty acid, with concomitant retardation of chilling injury.The breaking down of persimmon fruit cell wall fractions such as pectin, hemicellulose and cellulose are caused by cell wall hydrolases such as PE, PG, P -Gal, Xyl and Cx. The activities of endo-PG, 0 -Gal and Xyl in HAT(48C,3h) fruits were significantly higher than control, and little or no differences among the activities of PE, exo-PG and Cx of heat treated and control fruits. In chilling injuried fruits endo-PG, P -Gal and Xyl were inhibited, and CSP, SSP ASP andASH could not be normally broken down, and fruits failed to ripening normally.CWM content of persimmon fruits declined little during cold storage. When returned to 20C to ripen, CWM content declined rapidly. The CWM content of HAT fruits was lower than that of control. There was little change in the cell wall composition content and relative viscosity during cold storage. When returned to 20C to ripen, WSP content increased rapidly, while the relative viscosity declined rapidly. WSP content of HAT was significantly higher than that of control, while WSP relative viscosity of HAT was signifi...
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