Establishment of the Technique System of in vitro Polyploidy Induction for Stevia rebaudiana Bertoni
The stem sections of Stevia rebaudiana Bertoni were used as explants for polyploidy induction in vitro with different concentrations of colchicines for different time treatments during shoot formation.It was investigated that the best concentrations of colchicines and suitable treatment time in order to establish the technique system of polyploidy induction in vitro for Stevia rebaudiana Bertoni.There was great effect of colchicines on plantlet formation from stem section.The best treatment of colchicines was the concentration 0.1% for 3 d,and the ratio of polyploidy was 42.3%.Meanwhile,the treatment of colchicines could influence the shoot rooting.The leaves of polyploidy became thick and solid,the leaf colour changed dark and the plantlets got dwarf.The lower epidermal stomata of the polyploidy got bigger.The nucleus of the polyploidy cell was bigger and the number of chromosomes was doubled.