Potato infusion   500.0ml

Sucrose         20.0g

Agar           20.0g

Distilled water   500.0ml

自然pH                                                                                    

[note]Stripped and diced potato 1800g, wrap them with cloth and put the pack into 4500ml of water; boil for 10 minutes, then discard the potato dices; autoclave at 15 lb for 20 min., and store the infusion in refrigerator for usage.