Abstract：'Xuehua' is one of main cultivars of pears (Pyrus bretschneideri) in China, but the appearance quality is seriously affected by its rough surface, large fruit dot and other peel characters. In this study, according to peel characters, the young fruit were sprayed with a concentration of 200 mg/L chlorogenic acid (CGA) every week from 4 weeks after full bloom. The results showed that, compared with water spray (control), the fruit surface became relatively smooth and the fruit dot became significantly smaller after sprayed with CGA. When the fruit was mature, the firmness and index of absorbance difference (IAD) of pericarp chlorophyll became significantly lowered, but the single fruit weight, soluble solid content (SSC), titratable acid (TA) and peel color values of L, a, b were significantly increased. At the same time, compared with the control, spraying CGA could significantly reduce the lignin content and increase the total CGA content in the peel, and reduce the activity of phenylalanine ammonialyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) in the peel most of time, but had little effect on the activity of cinnamyl alcohol dehydrogenase (CAD). In addition, the gene expression of PAL1, POD2, PPO1, PPO4, PPO5, PPO6, CAD2 and CAD3 were significantly down-regulated in the early post-spray application period. In a word, the results of this study indicated that exogenous spraying of CGA could inhibit the lignin synthesis in the peel and the increase of fruit dot areas, and improve the skin characteristics of 'Xuehua' pear, which provides a new idea and basis for the effect of exogenous chlorogenic acid on the appearance quality of 'Xuehua' pear fruit.
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