Abstract: In order to analyze the effect of exogenous ethylene on the cuticular wax of Korla fragrant pear during accelerated ripening, a comparative analysis on the extraction yield and chemical composition of cuticular wax from pears soaked in ethephon solutions (250, 500 and 1 000 mg/L) was carried out by gas chromatography-mass spectrometry. Simultaneously, the changes in physiological indexes were determined. Compared with the non-treated control group, all concentrations of ethephon accelerated the ripening of the fragrant pear, remarkably increasing the respiratory rate on day 40 and ethylene release on day 60 (P < 0.05), advancing the peak of respiration and ethylene release, and increasing the content of water soluble pectin (WSP) and the enzyme activity of polygalacturonase (PG) and cellulase (CX), and the best effect was observed at 1 000 mg/L ethephon concentration. At the same time, ethephon at concentrations of 250 and 1 000 mg/L promoted the degradation of cellulose, and at 500 mg/L promoted the increase of relative conductivity. During the first 40 d of storage, ethephon treatment increased the extraction yield of total wax, being the most effective at a concentration of 1 000 mg/L. Ethephon treatment also promoted the formation of alcohols, saturated fatty acids, aldehydes, esters and olefins in the wax, but reduced the relative content of alkanes. Moreover, 500 and 1 000 mg/L ethephon also promoted the formation of enoic acids. In summary, ethephon could accelerate changes in cuticular wax contents and components while promoting the ripening of Korla fragrant pear.

Key words: Korla fragrant pear, ethephon, cuticular wax, gas chromatography-mass spectrometry