Investigation of Factors Influencing Browning During Callus Induction in Symplocos paniculata Seed Embryos

To investigate the factors influencing seed embryo tissue browning of Symplocos paniculata Thunb. Miq. during storage and callus induction, the physiological changes of seeds during storage were determined and the effects of different treatments on subsequent tissue culture were inverstigated, including browning rate, induction rate, and pollution rate. Test results showed that the activity of polyphenol oxidase（PPO） and content of malonaldehyde（MDA） were at their lowest levels after storing S. paniculata seeds at 4 ℃ for 14 days, and the browning rate of seed embryo tissue culture during this period was lowest. The high browning rate of S. paniculata seeds embryo tissue culture was found at both high（6.3） and low（4.8） pH levels, while the lowest browning rate was observed at pH of 5.8. During tissue culture inoculation, the endosperm was excised and the culture medium was adjusted to a pH of 5.3 with a sucrose-glucose mixture（1∶1） at a carbon concentration of 30 g/L. The addition of NAA at a concentration of 0.10 mg/L resulted in the production of numerous calli exhibiting robust growth and strong differentiation potential.