LED White Light Treatment Delays Postharvest Senescence of ‘Zaosu’ Pear Fruit with Inhibited Chlorophyll Degradation

Abstract

To investigate the effects of LED white light treatment (LWT) on the storage quality of postharvest ‘Zaosu’ pears, as well as its role in maintaining fruit greenness and delaying senescence, pear fruits were treated with intermittent irradiation using LED white light for 12 h per day, with a light source distance of 30 ± 1 cm and a photon flux density of 151 μmoL/(m2·s) at 25 °C. The results showed that LWT preserved the postharvest quality of ‘Zaosu’ pear fruit by reducing weight loss and ascorbic acid degradation and promoting the ratio of sugar and organic acid. Meanwhile, LWT also substantially inhibited the respiration intensity and ethylene production during the storage process. Accordingly, the expressions of genes related to ethylene biosynthesis and signaling were reduced in LWT fruit. Notably, LWT retarded the decrease in chlorophyll content of fruit by increasing the activities of enzymes associated with chlorophyll synthase. Additionally, LWT also suppressed the chlorophyll degradation-related enzymes and their gene expressions in pear peel. These findings suggest that a moderate light irradiation can delay the de-green progress and benefit post-harvest storage of ‘Zaosu’ pear.