Lignification Of Bamboo Shoots Research Articles

Study on the Regulation Mechanism of 1-MCP Combined with SO2 Treatment on Postharvest Senescence of Bamboo Shoots (Chimonobambusa quadrangularis) in Karst Mountain Area

Fresh bamboo shoots (Chimonobambusa quadrangularis) are subjected to senescence (e.g., lignification and browning) during postharvest storage. This study investigated the effects of 1-MCP and SO2 treatment on bamboo shoot senescence and its regulation mechanism in order to extend bamboo shoot storage time. 1-MCP and SO2 treatments significantly inhibited the browning and lignification of fresh bamboo shoots during storage, according to the results. Its lower browning index and lignin content are directly related to its lower lignin content compared to the CK control group. The browning index and lignin content of the 1-MCP + SO2 treatment during the late storage period were 90.55% and 81.50% of the CK treatment, respectively. The result of the in-depth analysis suggested that 1-MCP and SO2 treatments reduced nutrient loss and maintained the nutritional value of bamboo shoots by inhibiting respiration and physiological metabolism. The PPO activity was inhibited to inhibit the browning process. Moreover, the scavenging ability of ROS was enhanced, the accumulation of MDA was inhibited, and the senescence of bamboo shoots was delayed after higher contents of total flavonoids and ascorbic acid were maintained and the activities of ascorbic acid peroxidase and superoxide dismutase were stimulated. Furthermore, lignin biosynthesis was hindered, and the lignification of bamboo shoots was delayed after the activities of POD and PAL were inhibited. In brief, 1-MCP + SO2 treatment is capable of inhibiting the physiological metabolism, browning, and lignification of bamboo shoots, maintaining good quality during storage, and delaying the senescence of bamboo shoots. Clarifying the senescence mechanism of bamboo shoots is of great significance for expanding the bamboo shoot industry and slowing down rocky desertification in karst mountainous areas.

Comparative Analysis of the Lignification Process of Two Bamboo Shoots Stored at Room Temperature.

Two types of bamboo shoots, high bamboo (Phyllostachys prominens) shoots (HBSes) and moso bamboo (Phyllostachys edulis) shoots (MBSes), underwent a fast post-harvest lignification process under room temperature storage. To explore the mechanism of lignification in two types of bamboo shoots after post-harvest during room temperature storage, the measurement of cell wall polymers (lignin and cellulose) and enzyme activities of phenylalanine ammonialyase (PAL) and peroxidase (POD), and relative expression of related transcription networks factors (TFs) were performed. The results suggested that the lignification process in HBSes is faster than that in MBSes because of incremental increase in lignin and cellulose contents within 6 days and the shorter shelf-life. Additionally, compared with the expression pattern of lignification-related TFs and correlation analysis of lignin and cellulose contents, MYB20, MYB43, MYB85 could function positively in the lignification process of two types of bamboo shoots. A negative regulator, KNAT7, could negatively regulate the lignin biosynthesis in two types of bamboo shoots. In addition, MYB63 could function positively in HBSes, and NST1 could function negatively in MBSes. Notably, MYB42 may function differently in the two types of bamboo shoots, that is, a positive regulator in HBSes, but a negative regulator in MBSes. Transcription networks provide a comprehensive analysis to explore the mechanism of lignification in two types of bamboo shoots after post-harvest during room temperature storage. These results suggest that the lignification of bamboo shoots was mainly due to the increased activity of POD, higher expression levels of MYB20, MYB43, MYB63, and MYB85 genes, and lower expression levels of KNAT7 and NST1 genes, and the lignification process of HBSes and MBSes had significant differences.

Effect of nitric oxide on browning and lignification of peeled bamboo shoots

The effects of nitric oxide (NO) on browning and lignification of bamboo shoots were investigated. Bamboo shoots were dipped for 1 h in 0.5 mM sodium nitroprusside (SNP), a nitric oxide donor, then packed in 0.01 mm thick polyethylene bags, and stored for 10 days at 10 °C. SNP treatment inhibited activities of PPO, POD and PAL and maintained high total phenol contents, thus delaying external browning during storage. Furthermore, SNP treatment showed a significant inhibition of the synthesis of lignin and cellulose and delayed tissue lignification, indicating that application of NO may be a promising method for extending shelf-life and maintaining quality of peeled bamboo shoots.

Effect of modified atmosphere packaging on the browning and lignification of bamboo shoots

Fresh bamboo ( Phyllostachys praecox) shoots were stored in open or packaged circumstance at 10 °C to determine the effect of modified atmosphere packaging on the browning and lignification of the bamboo shoots. The packaging film was 0.04 mm polyethylene bags and the gas components were 2% O 2, 5% CO 2 and 93% N 2. The bamboo shoots of control treatment were not edible † at the end of the storage for severe browning, while the shoots of modified atmosphere packaging treatment browned slightly and remained edible. Modified atmosphere packaging treatment inhibited the formation of malondialdehyde and the activity of peroxidase and phenylalanin ammonialyase, which attributed to preventing the browning and lignification. Modified atmosphere packaging could not inhibit the formation of polyphenol and polyphenol oxidase activity, but the low O 2 concentration and the low activity of peroxidase and phenylalanin ammonialyase prevented the enzymatic reaction and maintained the bamboo shoots unbrowned. Modified atmosphere packaging treatment could also significantly inhibit the lignification of the bamboo shoots by preventing the formation of cellulose and lignin contents. ( †When the contents of cellulose and lignification of bamboo shoots was more than 46.64% and 15.63% (dry basis), it was inedible [Wang, J. W. (2002). Study on ageing physiology of postharvest of bamboo shoots. Forest Research 15 (6), 687–692].)

Role of O-Methyltransferase in the Lignification of Bamboo

Characterization of S-adenosylmethionine: catechol O-methyltransferase (EC. 2. 1. 1. 6) isolated from bamboo shoot was carried out. Ferulic and sinapic acids which are believed to be lignin precursors are formed by the mediation of the enzyme, and the enzyme activity increased progressively during the lignification of bamboo shoots. Evidences suggest that this enzyme may contribute to the synthesis of lignin precursors.

Role of Phenylalanine Deaminase and Tyrase in the Lignification of Bamboo

A pronounced increase of the activity of phenylalanine deaminase and tyrase during the lignification of bamboo shoots was observed. With progressing maturation from the basal part to the upper part of immature bamboos the pattern of the activity of the enzymes moved toward the upper part of the tissues, where the most active lignification was taking place, and the amount of cinnamic acid derivatives in the tissues was found to be in good accordance with the activity of the enzymes. l-Phenylalanine-G-14C and l-tyrosine-G-14C were both well incorporated into the lignin of bamboos. These results indicate that phenylalanine deaminase and tyrase are synthesized progressively just before the lignification of the bamboos and by the enzymes l-phenylalanine and l-tyrosine are deaminated to cinnamic acid derivatives and incorporated into lignin.

Role of Phenylalanine Deaminase and Tyrase in the Lignification of Bamboo

A pronounced increase of the activity of phenylalanine deaminase and tyrase during the lignification of bamboo shoots was observed. With progressing maturation from the basal part to the upper part of immature bamboos the pattern of the activity of the enzymes moved toward the upper part of the tissues, where the most active lignification was taking place, and the amount of cinnamic acid derivatives in the tissues was found to be in good accordance with the activity of the enzymes. l-Phenylalanine-G-14C and l-tyrosine-G-14C were both well incorporated into the lignin of bamboos. These results indicate that phenylalanine deaminase and tyrase are synthesized progressively just before the lignification of the bamboos and by the enzymes l-phenylalanine and l-tyrosine are deaminated to cinnamic acid derivatives and incorporated into lignin.