The influence of different factors on callus induction of Dioscorea opposita

The effects of genotypes, explants, phytohormones, light and dark etc.upon callus induction of Dioscorea opposita were studied. Results showed: (1)Different genotypes of D.opposita could all induce and form calli,but percentages of calli were different, which were in turn : D.opposita “No 47” D.opposita “Tiegun” D.opposita “Taigu”. (2)Different explants had obvious diversity on the same medium. The percentages of calli of the same explant were different on the media supplied with different phytohormones concentration. The combination 6 BA 2(mg/L)+NAA 2 was best to callus induction from leaf,stem,bulbil,whose ratios were respectively 53 3%,65 6%,100%.The combination 6 BA 2+NAA 0 2 was to shoot tip,whose ratio was 93 3%.(3)It was crucial for phytohormones to induce callus of D.opposita . Cytokinin and auxin combinations had better effect than single phytohormone,and their concentrations were different,ratio was different, too. (4)The effects of light and dark upon callus induction from different explants were different. The dark culture was more advantageous to induction from bulbil. The light culture was beneficial to leaf.