Ricinus communis L.is a new copper hyperaccumulator growing on Tonglushan copper mine in Hubei Province,China.This study aimed to establish a suspension cell line of R.communis L.with stable and rapid growth for further screening of heavy metal-resistant R.communis L.cells and breeding of hyperaccumulators.In this study,cell suspension culture conditions were optimized by using orthogonal experimental design with previously induced R.communis L.embyrogenic calluses as experimental materials,to establish the suspension cell line of R.communis L.Under the optimal conditions,growth curves of suspension cells and changes in pH of culture liquid were determined.The results showed that the optimal culture conditions for R.communis L.suspension cell line were:MS+0.5 mg/L 6-BA+0.2 mg/L NAA+50 mg/L sucrose+350 mg/L casein hydrolysate as basic medium,with callus inoculation amount of 2.5 g/50 ml,dark culture at(26±2)℃with shaking at 110 r/min.Under these conditions,increment of fresh weight and dry weight of R.communis L.suspension cells reached the maximum of 4.56 g/(50 ml·14 d)and 0.49 g/(50 ml·16 d),respectively.Growth curves of R.communis L.suspension cells were basically in"S"shape.Each culture cycle lasted 16 d,and the rapid growth stage was from the 6thd to the 14thd.In a culture cycle,pH of the culture liquid declined first and then increased to the maximum and stabilized gradually.
