该试验以“井岗红糯”荔枝为材料，研究采前100 mg/L脱落酸（Abscisic acid，ABA）处理对常温贮藏荔枝采后品质的影响。结果表明：采前ABA处理明显延缓了果实褐变指数、病情指数和腐烂率的升高，保持较好的色度值（L*、a*和b*），贮藏8 d ABA处理荔枝的褐变指数、病情指数、腐烂率分别为3.38、1.42和37.78%。贮藏8 d时，ABA处理荔枝果皮总酚含量、以及苯丙氨酸解氨酶（PAL）、多酚氧化酶（PPO）和过氧化物酶（POD）活性分别较对照高3.54%、1.38%、3.22%和18.39%；相对电导率（REC）、丙二醛（MDA）以及过氧化氢（H2O2）含量分别较对照低23.25%、11.85%和18.18%。此外，ABA处理荔枝果肉的可溶性固形物（TSS）、可滴定酸（TA）、维生素C（Vc）含量分别为17.70%、0.12%和30.14 mg/100 g，均高于对照。可见采前ABA处理不仅可以通过维持细胞膜完整性、减少酚类物质氧化、提高相关防御酶活性维持采后荔枝的外观品质，而且可以通过减缓TSS、TA和Vc含量的降低维持采后荔枝的营养品质。

The effects of preharvest application of 100 mg/L abscisic acid (ABA) on the preservation of lychee fruits stored at 20 ℃ were explored. The ‘Jingganghongnuo’ cultivar was selected for this research. Preharvest ABA treatment clearly mitigated increases in browning index, disease index, and fruit decay rate and better maintained the original color (L*, a*, and b*). More specifically, the browning index, disease index, and fruit decay rate of the ABA-treated lychee fruits were 3.38, 1.42, and 37.78%, respectively. After 8 days of storage, the total phenol content in the ABA-treated fruits was 3.54% higher than that in the control group, and the activities of phenylalanine ammonia-lyase, polyphenol oxidase, and peroxidase were 1.38%, 3.22%, and 18.39% higher, respectively. In contrast, relative electrical conductivity, malondialdehyde content, and hydrogen peroxide content were 23.25%, 11.85%, and 18.18% lower in ABA-treated fruits than in the control group, respectively. In addition, after 8 days of storage, the ABA-treated fruits had a total soluble solid (TSS) content of 17.70%, a titratable acid (TA) content of 0.12%, and a vitamin C (Vc) content of 30.14 mg/100 g, which were all higher than those in the control group. These results indicate that preharvest ABA treatment can maintain the appearance of harvested lychee fruits by maintaining cell membrane integrity, reducing the oxidation of phenols, and increasing the activity of antioxidant enzymes, as well as preserving nutritional quality by inhibiting decreases in TSS, TA, and Vc contents. Therefore, preharvest ABA treatment is recommended as a new technology for effectively maintaining the quality of harvested lychee fruits at ambient temperatures.

国家荔枝龙眼产业体系采后贮藏与保鲜岗（CARS-32-15）