Effect of Near-Freezing Temperature Storage on Delaying Postharvest Lignification of Dendrocalamus brandisii Shoots

In this study, the regulatory effect of near-freezing temperature (NFT) storage on postharvest lignification of Dendrocalamus brandisii shoots was evaluated. Samples stored at room temperature and 4 ℃ served as controls. Respiratory intensity, mass loss rate, hardness, H2O2 content, lignin content, and the activities and gene expression of key enzymes involved in lignin synthesis were measured during storage. The results showed that compared with the controls, NFT storage significantly inhibited the increase of respiration intensity, mass loss, hardness, H2O2 content and lignin content in D. brandisii shoots, and delayed the increase of phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), cinnamate 4-hydroxylase (C4H), and peroxidase (POD) activities. Transcriptomic analysis showed that 33 genes members in PAL, 4CL, HCT, CCR, and CAD families were down-regulated and 25 gene members were up-regulated. Correlation analysis revealed that most physiological indexes and the activities and gene expression of key enzymes involved in lignin synthesis were significantly and positively correlated with the lignin content. In conclusion, NFT storage could effectively suppress the lignification of D. brandisii shoots during storage by regulating the respiratory intensity, mass loss rate, hardness, H2O2 content, lignin content, and key enzyme activities and gene expression related to lignin synthesis.