Recent Trends in Small Molecule Gases for Maintaining the Postharvest Quality of Horticultural Products: A Review.

Most horticultural products are highly perishable, which seriously affects their shelf life and postharvest quality. Thus, there is an urgent demand for innovative preservation techniques to reduce postharvest losses. In recent years, small-molecule gases small-molecule gases have been found to be involved in regulating the postharvest quality of horticultural products. These compounds include nitric oxide (NO), ethylene (ETH), hydrogen (H2), carbon monoxide (CO), hydrogen sulfide (H2S), carbon dioxide (CO2), and hydrogen peroxide (H2O2). This review discusses the functions and mechanisms of small signaling molecules involved in the postharvest quality of horticultural products. In addition, the crosstalk between these compounds in the preservation of horticultural products has been emphasized. Small-molecule gases improve the postharvest quality of horticultural products by modulating the levels of reactive oxygen species (ROS), regulating ETH biosynthesis, modulating antioxidant systems, increasing secondary metabolites, regulating the expression of senescence-related genes, participating in signaling, and activating resistance pathways to mitigate cold damage and enhance disease resistance. Research has focused on the role of synergies between gas molecules in the postharvest stages of horticultural products. Thus, the role of small-molecule gases in improving the postharvest quality of horticultural products is a potential direction for future research.