Effects of Different Explants and Plant Growth Regulators on Callus Induction of Dioscorea zingiberensis

Using stems and leaves as explants,the effects of different plant growth regulators on callus induction of Dioscorea zingiberensis C.H.Wright were studied.The results indicated that stems were better explants for callus induction than leaves.The optimum callus induction medium for stems was MS+1.5 mg / L 2,4-D+1.0 mg / L 6-BA,as the induction rate could reach up to 100%.The callus was light yellow,loose and graininess.Using leaves as explants,the optimum callus induction medium was MS+1.0 mg / L 2,4-D +0.5 mg / L 6-BA,as the induction rate was 93.75%.Growth curve of callus was S-like and could be divided into three phases,lag growth phase(0～12 d),log growth phase(12～30 d) and slow growth phase(30～ 36 d),thus the subculture of callus should be carried out within 30 d after inoculation.