The aim of this study was to explore the role of abscisic acid (ABA) in ethanol fermentation during postharvest ripening of Nanguo pear fruit (Pyrus ussuriensis Maxim.). Pears harvest at commercial maturity were treated with 100 μmol L⁻¹ ABA or its biosynthesis inhibitor nordihydroguaiaretic acid (NDGA). Our data indicated that ABA treatment promoted respiration rate and ethylene production during ripening compared with controls, while NDGA treatment had the opposite effects. During the early ripening stage, flesh firmness in ABA treatment group was lower than in controls; while in NDGA treatment group, it was higher than in controls. The contents of glucose, ethanol and acetaldehyde were increased by ABA treatment while reduced by NDGA treatment during ripening compared with the controls. ABA treatment promoted pyruvate and acetyl-CoA contents, whereas application of NDGA reduced pyruvate content and delayed the peak of acetyl-CoA content compared with the controls. The oxaloacetic acid (OA) and citric acid (CA) contents were reduced by ABA treatment while increased by NDGA treatment during ripening. ABA treatment promoted pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) activities, whereas NDGA treatment reduced their activities mainly at the early ripening stage. Quantitative real-time polymerase chain reaction (qPCR) showed that expression of PDC1, ADH1 and ADH2 was differentially up-regulated by ABA treatment during ripening while down-regulated by NDGA treatment compared with the controls. PDC2 expression was enhanced after application of NDGA during ripening while reduced by ABA treatment at the early ripening stage. Our data indicated that ABA had a promoting effect on ethanol fermentation during ripening of Nanguo pear fruit.

本研究的目的是探讨脱落酸（ABA）在南果梨果实（Pyrus ussuriensis Maxim .）采后成熟过程中乙醇发酵中的作用。商业成熟时收获的梨用 100 μmol L ^-1ABA 或其生物合成抑制剂去甲二氢愈创木酸 (NDGA)。我们的数据表明，与对照相比，ABA 处理促进了成熟过程中的呼吸速率和乙烯产生，而 NDGA 处理具有相反的效果。在早熟阶段，ABA处理组果肉硬度低于对照组；而NDGA治疗组高于对照组。与对照相比，在成熟过程中，ABA处理增加了葡萄糖、乙醇和乙醛的含量，而NDGA处理降低了其含量。与对照组相比，ABA 处理提高了丙酮酸和乙酰辅酶 A 含量，而 NDGA 的应用降低了丙酮酸含量并延迟了乙酰辅酶 A 含量的峰值。在成熟过程中，ABA 处理降低了草酰乙酸 (OA) 和柠檬酸 (CA) 的含量，而通过 NDGA 处理增加了它们的含量。ABA 处理促进了丙酮酸脱羧酶 (PDC) 和乙醇脱氢酶 (ADH) 的活性，而 NDGA 处理主要在早熟阶段降低了它们的活性。定量实时聚合酶链反应 (qPCR) 表明与对照相比，PDC1、ADH1和ADH2在成熟期间被 ABA 处理差异上调，而被 NDGA 处理下调。PDC2表达在成熟期间应用 NDGA 后增强，而在早熟阶段通过 ABA 处理降低。我们的数据表明ABA对南果梨果实成熟过程中的乙醇发酵有促进作用。