【摘要】 梨果肉褐变是影响其品质的重要问题，为深入探讨梨果肉褐变的生理机制，以易褐变品种‘宝珠’‘苹果梨’和不易褐变品种‘丰水’‘崇化大梨’为试验材料，测定其果实发育过程中褐变度、酚类物质及相关酶活性的变化。结果表明，梨果肉褐变程度、酚类物质含量和部分酶活性均随着果实的生长发育呈逐渐降低的趋势；从幼果至果实成熟，熊果苷、绿原酸、表儿茶素是果实中主要的酚类物质，三者含量占总酚含量的90%以上，2个易褐变品种‘宝珠’‘苹果梨’果实中熊果苷、绿原酸含量高于2个不易褐变品种‘丰水’‘崇化大梨’。从果实褐变度与酚类物质含量的相关性分析看，在幼果期，单个的酚类物质对果实褐变影响不大，在果实生长后期与果实褐变相关性强的酚类物质主要有熊果苷、儿茶素、绿原酸和咖啡酸。在整个果实发育期，易褐变品种的多酚氧化酶（PPO）活性、苯丙氨酸解氨酶（PAL）活性和总酚含量均高于不易褐变品种；幼果期易褐变品种果实PPO活性与不易褐变品种差异显著（P<0.05），成熟期差异不显著。4个品种果实中PPO、PAL活性与大多数酚类物质含量均显著相关，对不同发育阶段果实褐变的研究要综合考虑PPO活性与总酚的含量。更多还原

【Abstract】 Browning of pear flesh is an important problem affecting its quality. In this experiment,Browning varieties‘Baozhu’,‘Pingguoli’and non-browning varieties‘Fengshui’,‘Honghuada’were used to study the physiological mechanism of pear flesh browning,by measuring the changes of browning degree,phenolics and related enzyme activities during fruit development. The results showed that the browning degree,phenolic content and some enzyme activities of pear flesh decreased gradually with The growth and development of the fruit. Arbutin,chlorogenic acid and epicatechin were the main phenolic compounds in pear fruit from young fruit stage to mature fruit stage,accounting for more than 90% of the total phenolic content. The contents of arbutin and chlorogenic acid in the fruits of the two browning varieties were higher than those of the two non-browning varieties. According to the correlation analysis between fruit browning degree and phenolic substance content,single phenolic substance had little effect on fruit browning in young fruit stage,and phenolic substance strongly correlated with fruit browning in late fruit growth were arbutin,catechin,chlorogenic acid and caffeic acid. In the process of fruit growth and development,the PPO,PAL activities and total phenol content of browning varieties were higher than those of non-browning varieties. The PPO activity of the browning varieties was significantly different from that of the non-browning varieties at young fruit stage(P < 0.05),and it was not significantly different at mature fruit stage. The activities of PPO and PAL were significantly correlated with the contents of most phenolic substances in the fruits of the four varieties. The study on fruit browning at different development stages should take PPO activity and total phenolic content into consideration.更多还原