Effects of exogenous nitric oxide on contents of soluble sugars and related enzyme activities in ‘Feicheng’ peach fruit

Abstract

Sugar content is one of the main characteristics related to the quality of fruit. Research confirms that nitric oxide (NO) involves a physiological process and prolongs the storage life of fruit. However, little attention has been paid to the effects of NO on sugar metabolism in fruit during storage. In this study, the effect of different concentrations (0, 10, 30 µmol L⁻¹) of exogenous NO treatment on sugar content and related enzyme activities in 'Feicheng' peach fruit was investigated during storage (0-12 days after harvest) at room temperature (25 °C). Results showed that the decrease of firmness and accumulation of sugar and acid:sugar ratio in peach fruit during storage were significantly inhibited by treatment with 10 µmol L⁻¹ NO. Treatment with 10 µmol L⁻¹ NO could promote fructose and glucose metabolism during the first 4 days of storage, and increase the content of sucrose and the activities of sorbitol dehydrogenase, sorbitol oxidase and sucrose phosphate synthase in peach fruit during storage. However, acid invertase activity from 8 to 12 days of storage and neutral invertase activity during the first 4 days of storage were inhibited by treatment with 10 µmol L⁻¹ NO. At the same time, treatment with 10 µmol L⁻¹ NO inhibited sucrose synthase (SS) activity in decomposition during storage and SS activity in synthesis from 8 to 12 days of storage. Treatment with 10 µmol L⁻¹ NO had a significant impact on content of soluble sugars and related enzyme activities in 'Feicheng' peach fruit during storage (0-12 days) at room temperature (25 °C).