采后乙烯利处理对库尔勒香梨蜡质组分的影响

Effect of Postharvest Ethephon Treatment on Peel Wax Composition of Korla Fragrant Pear

为了分析外源乙烯加速香梨成熟过程中对表皮蜡质的影响,通过气相色谱-质谱联用技术对乙烯利(250、500、1 000 mg/L)浸泡的库尔勒香梨的表皮蜡质提取量及组分进行分析比较,同时测定香梨果实生理指标变化。结果表明:与对照组相比,不同质量浓度乙烯利处理均加速了香梨的成熟,使贮藏40 d时的呼吸强度和贮藏60 d时的乙烯释放量显著增加(P<0.05),并使呼吸高峰和乙烯释放高峰提前,提高水溶性果胶质量分数和多聚半乳糖醛酸酶、纤维素酶活力,质量浓度为1 000 mg/L时效果最明显;同时250、1 000 mg/L乙烯利处理促进纤维素降解,500 mg/L乙烯利对相对电导率的升高有促进作用。在贮藏0~40 d之间,乙烯利处理提高了香梨总蜡质提取量,其中1 000 mg/L乙烯利处理作用最显著。乙烯利处理对蜡质中醇类、饱和脂肪酸、醛类、酯类和烯烃的生成均有促进作用,但降低了烷烃相对含量,500、1 000 mg/L乙烯利对烯酸的生成也有促进作用。综上,乙烯利促进香梨成熟的过程中伴随着表皮蜡质含量及组分的变化。

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.