Preharvest application of hydrogen-rich water not only affects daylily bud yield but also contributes to the alleviation of bud browning

Abstract Although previous studies have suggested that post-harvest hydrogen (H2) treatment can regulate the senescence of plant tissues, it was not clear whether preharvest treatment had a similar effect. The present study showed that the preharvest irrigating with hydrogen-rich water (HRW), increased the yield of daylily buds, and alleviated the chilling injury symptoms such as decreased sepal browning, which was associated with decreasing reactive oxygen species level, leakage rate and lipid peroxidation, as well as increasing the unsaturated:saturated fatty acid ratio and endogenous H2 content. In addition, the HRW-treated buds exhibited significantly lower phenylalanine ammonia lyase and polyphenol oxidase enzyme activity, which contributed to the total phenol accumulation being higher in HRW-treated buds than in the control. Overall, these results suggest that HRW preharvest treatment could be used as a useful technology for enhancing chilling tolerance of daylily buds, thus prolonging their useful storage life.