Exogenous 2,4-Epibrassinolide Treatment Maintains the Quality of Carambola Fruit Associated With Enhanced Antioxidant Capacity and Alternative Respiratory Metabolism

Xiaoyang Zhu; Yuxin Chen; Junyi Li; Xiaochun Ding; Shuangling Xiao; Silin Fan; Zunyang Song; Weixin Chen; Xueping Li

doi:10.3389/fpls.2021.678295

Exogenous 2,4-Epibrassinolide Treatment Maintains the Quality of Carambola Fruit Associated With Enhanced Antioxidant Capacity and Alternative Respiratory Metabolism

Front Plant Sci. 2021 Jun 4:12:678295. doi: 10.3389/fpls.2021.678295. eCollection 2021.

Authors

Xiaoyang Zhu¹, Yuxin Chen¹, Junyi Li¹, Xiaochun Ding¹, Shuangling Xiao², Silin Fan¹, Zunyang Song¹, Weixin Chen¹, Xueping Li¹

Affiliations

¹ Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center for Postharvest Technology of Horticultural Crops in South China, College of Horticulture, South China Agricultural University, Guangzhou, China.
² College of Land Resources and Environment, Jiangxi Agricultural University, Nanchang, China.

Abstract

Brassinosteroids act by delaying fruit ripening. The effects of different concentrations of 2,4-epibrassinolide (eBL) treatments on carambola fruit ripening were investigated. The results show that treatment of 2.8 mg L^-1, eBL with 10 min effectively delays ripening and maintains the quality of carambola fruit. This is achieved by retarding color changes and firmness losses while maintaining high level of soluble protein content and vitamin C, and low organic acid content. eBL-delayed senescence may be due to the inhibition of respiration rate and enhanced antioxidant system. It is noteworthy that eBL treatment markedly reduces the content of fructose-6-phosphate (6-P-F) and enhances the activity of cytochrome oxidase (CCO), and the total activity of glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphate gluconate dehydrogenase (6-PGDH). eBL treatment induces the IAA and GA contents but reduces that of ABA. In general, senescence retardation and quality improvement by eBL treatment may be due to the enhanced antioxidant capacity and altered respiratory pathways.

Keywords: antioxidant capacity; brassinolide; carambola fruit; fruit quality; respiratory metabolism.