Effects of Different Hormone Concentrations on Callus Induction of Astragalus mongholicus Bunge

Abstract

A method of callus induction and subculture of Astragalus mongholicus was established. Different methods were used to sterilize seeds to induce sterile seedlings. The different parts of plants and Astragalus aseptic seedlings were used for the explants, different concentrations of auxin NAA and Cytokinin BAP were used in MS medium to induce callus, and then the callus with better growth condition was selected for secondary culture. Results showed that the browning phenomenon in the secondary culture was inhibited and the best disinfectant was mercuric chloride. The germination rate of seeds treated with 75% ethanol for 40 s, 1.5% NaCl for 20 minutes, and 0.1% HgCl2 for 3 minutes can reach up to 66.2%. The hypocotyls of sterile seedlings as explants were the best way to induce callus. The induction rate was close to 100% when 0.5 mg/L BAP and 0.15 mg/L of NAA and 0.01 mg/L of nano-TiO2 were added to MS medium. Besides, Nano-TiO2 can effectively prevent bacterial contamination of MS medium. Cotyledons, induced by cotyledon as explants, showed the most severe browning. Therefore, the best hormone combination of Astragalus subculture was 1.0 mg/L BAP, 1.5 mg/L NAA and 0.01 mg/L nano-TiO2 .