Tissue culture and generation of autotetraploid plants of Sophora flavescens Aiton.

Sophora flavescens Aiton is an important medicinal plant in China. Early in vitro researches of S. flavescens were focused on callus induction and cell suspension culture, only a few were concerned with in vitro multiplication. To establish and optimize the rapid propagation technology of S. flavescens and to generate and characterize polyploid plants of S. flavescens. The different concentrations of 6-benzylaminopurine (BAP), indole-3-acetic acid (IAA) and kinetin (KT) were used to establish and screen the optimal rapid propagation technology of S. flavescens by orthogonal test; 0.2% colchicine solution was used to induce polyploid plants and the induced buds were identified by root-tip chromosome determination and stomatal apparatus observation. A large number of buds could be induced directly from epicotyl and hypocotyl explants on the Murashige and Skoog medium (MS; 1962) supplemented with 1.4-1.6 mg/l 6-benzylaminopurine (BAP) and 0.3 mg/l indole-3-acetic acid (IAA). More than 50 lines of autotetraploid plants were obtained. The chromosome number of the autotetraploid plantlet was 2n = 4× = 36. All tetraploid plants showed typical polyploid characteristics. Obtained autotetraploid lines will be of important genetic and breeding value and can be used for further selection and plant breeding.