Microenvironment Control Of Virus-free Potato Plantlets During Bioreactor Culture

Potatoes are mainly vegetatively propagated:Field-grown potato has been easily affected by yirus infection which results in heavy loss in yield.Establihing a method of meristem tip culture to achieve virus-free plantlets is the effevtive way to solve this problem.With the expansion.of cultivation area,demand for virus-free potato plantlets has increased,but the traditiomal culture using small vessel has problems of complicated operation,low efficiency and high cost.In order to make up for the shortcomings of traditional culture methods,we intended to use 5 L air-lift bioreactor system to culture stem explants of virus free potato ’Yanshu4’ plantlet and produce healthy plantlets.And we investigated different medium supply,the strength of the MS medium and ammonium/nitrate contents to determine their effects on plant growth in bioreactor cultures.The results are as follows:1.Different culture methods have significant effects on the growth of plantlets.The fresh weight,dry weight and leaf size of plantlets in immersion culture are significantly higher than other culture methods;2.The effect of different medium strength on the growth of plantlets has significant difference.In the treatment of 1/4,1/2 MS medium strength potato plantlets could not grow,but in the treatment of 1,3/2,2 MS medium strength the test plantlets could grow normally,and in the 2 MS medium strength,the test plantlets have the best growth state and the maximum biomass;3.The effects of different ammonium and nitrate nitrogen concentrations on test plantlets were different.When the concentration of ammonium nitrogen and nitrate nitrogen is 20:100 mmol·L-1,the growth of test tube seedlings was the best,and the biomass and plant height were significant.Compared with other treatments,the plantlets with the concentrations of 80:40 mmol·L-1 and 100:20 mmol·L-1 could not grow normally,indicating that the high concentration of nitrate nitrogen was suitable for the growth of plantlets,but the ammonium nitrogen content was too high could inhibit he growth of plantlets.Comprehensive research results,potato plantlets have the best grow state in immersion bioreactor culture;2 MS medium strength and concentration of ammonium nitrogen and nitrate nitrogen is 20:100 mmol·L-1 are the best culture conditions.