Effects of CaCl2 Treatment Alleviates Chilling Injury of Loquat Fruit (Eribotrya japonica) by Modulating ROS Homeostasis

Abstract

The effects of calcium chloride (CaCl₂) treatment on chilling injury (CI), reactive oxygen species (ROS) metabolism, and ascorbate-glutathione (AsA-GSH) cycle in loquat fruit at 1 °C storage for 35 d were investigated. The results indicated that CaCl₂ treatment remarkably suppressed the increase in browning index and firmness as well as the decrease in extractable juice rate. CaCl₂ treatment also decreased the production of superoxide radical (O2•-), hydrogen peroxide (H₂O₂) content, but increased the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (OH•) scavenging ability, the activities of superoxide dismutase (SOD), catalase (CAT), and their gene expressions. Moreover, compared to the control loquat fruit, CaCl₂-treated fruit maintained higher contents of AsA, GSH, higher levels of activities of ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR) and expressions of <i>EjAPX</i>, <i>EjGR</i>, <i>EjMDHAR</i>, and <i>EjDHAR</i>, but exhibited lower glutathione disulfide (GSSG) content. These results suggested that CaCl₂ treatment alleviated CI in loquat fruit through enhancing antioxidant enzymes activities and AsA-GSH cycle system to quench ROS.