牡丹多酚氧化酶的酶学特性

【目的】研究影响牡丹试管苗多酚氧化酶（PPO）酶学特性的因素，为牡丹的高效组培提供参考。【方法】以牡丹品种“乌龙捧盛”为供试材料，采用分光光度计比色法，研究温度、pH值、PPO提取液添加量及底物的类型和浓度对牡丹PPO活性的影响。【结果】以邻苯二酚为底物时，牡丹PPO的最适反应温度与最适pH分别为25 ℃和6.0，最适PPO提取液添加量为1 mL。牡丹PPO的最适作用底物为咖啡酸，其最适浓度为0.08 mol/L。【结论】通过选择合适的pH值和培养温度，同时结合化学抑制剂调控牡丹PPO活性，可以达到在牡丹组织培养中减少褐化现象、提高试管苗生根率的目的。

Study on characteristics of polyphenol oxidase in peony

【Objective】The research aimed to study the influence factors of the polyphenol oxidase characteristics of peony plantlet in vitro.【Method】With cultivar of "Wulongpengsheng" as experimental materials,the effects of temperature,pH value,PPO content,substrate type and concentration on PPO activity of Paeonia suffruticosa Andr were studied using spectrophotometry method.【Result】With catechol as substrate,the optimum reaction temperature and pH respectively were 25 ℃ and 6.0,the optimal adding amount of PPO 1 mL,the optimum substrate of PPO coffee acid,and the optimum concentration of coffee acid 0.08 mol/L.【Conclusion】Browning phenomenon can be induced and the rate of tissue culture plantlets can be improved by selecting the appropriate pH,temperature,and combining with the chemical inhibitors to regulate and control peony PPO enzymatic activity.