Regulation of Polyethylene Nano-Packaging on Postharvest Stipe Elongation of Flammulina velutipes

Stipe elongation is one of the main characteristics of the postharvest quality deterioration of Flammulina velutipes fruiting bodies. In order to reduce the postharvest stipe elongation of F. velutipes and prolong its shelf life, in this study, using polyethylene (PE) packaging and unpackaged treatments as controls, the effects of a polyethylene nano-packaging on postharvest stipe elongation of F. velutipes were investigated and its regulatory mechanisms were explored from the physiological and biochemical aspects. The results showed that the CO2 content in polyethylene nano-packaging boxes was higher than in control boxes, and the O2 content was lower than in the control group, indicating that nano-packaging could reduce F. velutipes respiration during low-temperature storage. The stipe elongation rate, chitinase activity, and β-1,3-glucanase activities of F. velutipes were lower in the nano-packaging group than in PE-packaged and unpackaged control groups, and the nano-packaging inhibited the increase in chitin and β-glucan, the main components of the cell wall. The levels of auxin (IAA), abscisic acid (ABA), gibberellin (GA), and cytokinin (CTK) were also lower in the nano-packaged group than in controls at most timepoints. After 18 d of storage, polyethylene nano-packaging inhibited the stipe elongation of fruiting bodies, and maintained mushroom quality, with stipe elongation of only 34.7% and 76.7% of PE-packaged and unpackaged control groups, respectively. The results showed that nano-packaging could effectively inhibit the harvest stipe elongation and prolong the shelf quality of F. velutipes.