Application of melatonin delays lignification in postharvest water bamboo shoots in association with energy metabolism

Lignification occurs in some vegetables and fruit after harvest and lowers their quality and commercial value. This study investigated the effects of melatonin (MT) on the energy metabolism of postharvest water bamboo shoots (WBS) and their relationship with lignification. We found that lignin accumulation could result in insufficient energy in postharvest WBS. The ATP content of the melatonin treatment group was 1.7 times higher than that of the control. Melatonin slowed down the decrease in the energy status by activating succinic dehydrogenase (SDH), cytochrome c oxidase (CCO), H+-ATPase, Mg2+-ATPase, and Ca2+-ATPase, as well as the transcription levels of their corresponding genes in WBS. Moreover, melatonin treatment increased nicotinamide adenine dinucleotide phosphate (NADP) and nicotinamide adenine dinucleotide phosphate reduced form (NADPH) content by promoting nicotinamide adenine dinucleotide kinase (NADK) activity as well as by maintaining lower nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide reduced form (NADH) levels during storage. The correlation study revealed a negative relationship between lignin accumulation and energy metabolism in postharvest WBS. These findings supported the notion that the application of MT is a viable and effective method for alleviating lignification and supplying adequate energy to harvested WBS.