Endogenous Hydrogen Sulfide Homeostasis Is Responsible for the Alleviation of Senescence of Postharvest Daylily Flower via Increasing Antioxidant Capacity and Maintained Energy Status

There are limited data concerning the role of endogenous H 2 S in prolonging the postharvest of vegetables and fruits. Using a fluorescence microscope with a specific probe, we discovered that, during the senescence of postharvest daylily flower, endogenous H 2 S homeostasis was impaired. The activities of two important synthetic enzymes of H 2 S, l - and d -cysteine desulfhydrase, exhibited decreasing tendencies. However, NaHS (a H 2 S donor) not only blocked the decreased H 2 S production but also extended the postharvest life of daylilies. These beneficial roles were verified by the alleviation of lipid peroxidation and the increased activities of antioxidant enzymes. Meanwhile, the energy status was sustained, and the respiration rate was decreased. In contrast to NaHS, the addition of an inhibitor of H 2 S synthesis alone aggravated lipid peroxidation and lowered energy charge. Together, the present study implies that endogenous H 2 S alleviates senescence of postharvest daylilies via increasing antioxidant capacity and maintained energy status.