Callus Induction and Establishment of Cell Suspension Culture System for Thymus vulgaris L.

The stems and leaves of aseptic seedling of Thymus vulgaris L.were taken as explants to study the optimum culture conditions of callus induction and proliferation.In addition,the growth characteristics of suspension cell were investigated and the system of thymus cell suspension culture was established preliminarily.The results showed that stem explants were the most suitable for callus induction,the optimal medium for callus induction was MS + NAA 1.0 mg/L + 6-BA 0.5 mg/L+ 2,4-D 0.5 mg/L,the optimal formula for callus proliferation and suspension culture was MS + 6-BA 1.0 mg/L+ 2,4-D 0.1 mg/L and MS + 6-BA 0.5 mg/L+ 2,4-D 0.1 mg/L respectively.The growth of suspension cells exhibited an S-shaped curve and growth mass reached the maximum after 20 days' culture,the optimal subculture cycle was 18-20 d.In the process of suspension culture,the same change trends of pH value and conductivity were showed: firstly decreased then increased and then became stable,and the suspension cell number exhibited the change trend: firstly increased then decreased.