关键词: 富士苹果, 5-氨基乙酰丙酸, 酶活性, 贮藏品质, 货架品质, 植物生长调节剂

Abstract: In order to improve the storage quality of Fuji apple，the leaves were sprayed for three times at the fruit expansion stage with 0（water，CK），0.5，5，10 mg/L of exogenous 5‑aminolevulinic acid（ALA），respectively. The fruit hardness，total soluble solids（TSS） content，titratable acid（TA） content，malondialdehyde（MDA）content，the activities of peroxidase（POD）and polyphenol oxidase（PPO）of Fuji apple during cold storage（0—200 d）were investigated，and the shelf‑life quality of Fuji apple treated with the optimal mass concentration was analyzed.The results showed that spraying exogenous ALA on leaves could significantly promote apple fruit coloring，increase TSS content and decrease TA content in fruit flesh，and was beneficial to maintaining fruit hardness during cold storage，inhibiting the decrease of TSS content，and keeping higher POD activity，lower PPO activity and MDA content in apple fruit.Among them，10 mg/L ALA treatment had the best effect. After 200 days of cold storage，compared with CK，fruit hardness，TSS content，TA content and POD activity of 10 mg/L ALA treatment were increased by 7.5%，17.0%，45.5% and 69.5%，respectively，MDA content and PPO activity were decreased by 17.7% and 39.5%，respectively. At the same time，the fruit quality of Fuji apple stored at room temperature for 10 days after 200‑day refrigeration was maintained by this treatment，and the fruit hardness，TSS content and TA content were higher than those of the control. In conclusion，multiple spraying of exogenous ALA at 10 mg/L during fruit expansion stage could significantly improve the harvest quality and storage quality of Fuji apple fruit.

Key words: Fuji apple, 5-aminolevulinic acid, Enzyme activity, Storage quality, Shelf quality, Plant growth regulator