防褐剂对牡丹组培褐化发生、组培苗生长和增殖的作用

Effects of browning antagonists on antibrowning,growth and multiplication of tissue culture of tree peony

牡丹组培中褐化现象的发生,影响了组培苗的生长、增殖和组培过程的进行。该文研究了活性炭、硝酸银、PVPP和维生素C 4种防褐剂对牡丹品种‘乌龙捧盛’组培中褐化控制的作用及对组培苗生长和增殖的影响。结果表明：褐化集中发生在转接后4 d内。活性炭能有效控制褐化,但长时间处理会抑制组培苗的生长和增殖;继代培养初期在含活性炭2.0 g/L的培养基中进行4 d短期处理,不仅能有效控制褐化,还在一定程度上促进了组培苗的生长和增殖。硝酸银1.0-8.0 mg/L能明显减轻褐化,其中2.0 mg/L的效果最好并能显著促进增殖;8.0 mg/L时组培苗生长量最大。PVPP能部分控制褐化,1.0 g/L效果较好;低浓度的PVPP促进组培苗生长,高浓度时促进增殖。维生素C控制褐化的效果不佳,且易导致组培苗玻璃化。综合分析认为：牡丹品种‘乌龙捧盛’继代转接时,先在添加活性炭2.0 g/L的培养基中培养4 d,然后转入不含活性炭的培养基中,能有效控制褐化和避免活性炭对生长和增殖的负面影响;在培养基中加入硝酸银2.0 mg/L,能在有效控制褐化的同时,促进组培苗生长与增殖,推荐在牡丹组培中应用。

Browning occurring in tissue culture of tree peony restrains the growth and multiplication of propagators and success of micropropagation. Contrast tests of activated charcoal, silver nitrate, PVPP and vitamin C were designed in tissue culture of tree peony to study their effects on antibrowning, growth and multiplication of subculture propagators. Results showed that browning occurred during the first four days of subculture. Activated charcoal eliminated browning effectively but restrained growth and multiplication of propagators synchronously because of its absorbency on nutrient elements in culture media. A four-day treatment of 2.0 g/L activated charcoal after subculture initiation, also eliminated browning as well as promoted appreciably the growth and multiplication of propagators. Silver nitrate with concentrations of 1.0-8.0 mg/L controlled browning obviously, in which treatment of 2.0 mg/L was optimal to the antibrowning and multiplication of propagators and that of 8.0 mg/L was most effective to promote the growth of them. PVPP controlled browning to some extent. Its lower concentration benefited the growth, while the higher one promoted the multiplication. Vitamin C was not suitable for both antibrowning and development of the propagators. In conclusion, a twostep process, during which the subculture propagators were treated firstly in the culture media with activated charcoal 2.0 g/L for four days, then in the media without it, should be used in tissue culture of tree peony to obtain the best effect of antibrowning as well as promote the growth and multiplication of propagator to some extent. The inclusion of 2.0 mg/L silver nitrate in media should also be used to effectively control browning and promote the growth and multiplication of propagators.