Brassinolide Alleviates Chilling Injury of Sweet Cherry (Prunus avium L. cv. Tieton) during Cold Storage

Abstract

Brassinolide (BR) is a natural plant hormone that enhances stress resistance, preserving the freshness and quality of postharvest fruits. This study investigated the effects of exogenous BR on chilling injury, physiological characteristics, and antioxidant capacity in sweet cherries (Prunus avium L. cv. Tieton) during cold storage. Cherries were treated with distilled water (Control, CK), 2 μmol·L−1 BR (CL1), and 10 μmol·L−1 BR (CL2) for 30 min, then stored at 2 ± 1 °C for 28 d. Sampling occurred every 7 d to assess BR’s impact. BR treatment significantly reduced the chilling injury index (28 d values: CK 39.56%, CL1 14.22%, CL2 21.33%) and weight loss index (28 d values: CK 4.07%, CL1 1.00%, CL2 1.77%), and delayed the decline in fruit firmness and quality. Additionally, BR increased the sugar acid ratio, vitamin C, total phenolic, and flavonoid contents while reducing superoxide anion (O2−) and hydrogen peroxide (H2O2) accumulation. Notably, BR significantly lowered polyphenol oxidase (PPO) and peroxidase (POD) activities, with CL1 showing superior efficacy. The findings indicate that BR application can potentially reduce postharvest chilling injury in sweet cherries and maintain their quality after harvest, providing a theoretical basis for its application in sweet cherry storage and preservation.