JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (6): 167-174.doi: 10.12302/j.issn.1000-2006.202203071

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Effects of different anti-browning agents on enzyme activity and growth in callus of Cyclocarya paliurus

WANG Ji1,2(), FANG Shengzuo2,*()   

  1. 1. Nanjing Xiaozhuang University,Nanjing 211171, China
    2. College of Forestry and Grassland, Nanjing Forestry University, Nanjing 210037, China
  • Received:2022-03-21 Revised:2022-05-11 Online:2023-11-30 Published:2023-11-23
  • Contact: FANG Shengzuo E-mail:43826781@qq.com;fangsz@njfu.edu.cn

Abstract:

【Objective】The browning in the callus culture process of Cyclocarya paliurus is an important problem for the death of callus, which obviously restricts its large-scale production. Reducing the browning rate will lay the foundation for the establishment of a rapid propagation system and in vitro production of secondary metabolites. 【Method】The stem segments, leave and roots of C. paliurus seedlings were used as explants to study the effects of three different anti-browning agents, including vitamin C (VC), polyvinylpyrrolidone (PVP) and active carbon (AC) with different concentrations on the browning rate, increment as well as enzyme activities of C. paliurus callus. 【Result】Different anti-browning agents and their concentrations had significant effects on the browning rate, growth and activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) activity in C. paliurus callus (P < 0.05). The callus browning rate decreased with increasing PVP and AC concentrations, whereas the rate first decreased and then increased with increasing VC concentrations. Among them, the browning rate in callus of stem segments, roots and leaves was the lowest when the AC concentration of 4.0 g/L was added, reaching 16.3%, 33.3% and 26.7%, respectively. The growth of calli in the explants treated with VC and PVP was higher than that in the AC treatment. However, when the 0.4 g/L of VC was applied, the cumulative growth of calli in stem segments was the highest (6.69 g). With increasing concentrations of anti-browning agents, PAL activity in callus gradually decreased, whereas the activities of PPO and POD showed a unimodal trend. Moreover, the enzymatic activity of callus explants from leaves was higher than that of stem segments and roots. Pearson correlation analysis showed that callus browning rate was positively correlated with PAL activity(P < 0.01), whereas callus growth was positively correlated with PPO and POD activities(P < 0.01). 【Conclusion】The types and concentrations of anti-browning agents have a significant effect on the browning and growth of C. paliurus callus. AC has the best anti-browning effect, but somewhat inhibits callus growth. PAL enzyme activity plays a key role in preventing callus browning, and the selection of explant organs is crucial during tissue culture of C. paliurus.

Key words: Cyclocarya paliurus, tissue culture, explant, callus, browning rate, enzyme activity

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