Induction Culture of Callus from Apple Leaves

In order to obtain better callus,the leaves of Ralls and Fuji apple were used as explants,and the effects of different disinfection methods,types and concentrations of plant growth regulators,light conditions and ways of explants touching medium on callus induction were studied.The results were as follows.(1) The callus induction rate of only light culture after inoculation was only 50%~55%.But after dark culture for 14 or 21 days and then light culture,the callus induction rate reached to 100%,and yellow calluses with tight structure were obtained from the former,while albino ones with loose structure were obtained from the latter.Dark culture for 14 days was advantage to callus formation.(2) The MS basic medium with no hormone was beneficial to reducing the browning rate compared to the MS medium with added hormones.(3) The induction rate could increased by 25%~30% and the callus formation time was earlier with the leaf abaxial surface contacting medium compared to using the leaf adaxial surface contacting medium.(4) The suitable medium for callus formation of Ralls and Fuji leaves were MS+ 2.0 mg/L 6-BA +0.2 mg/L NAA and MS+1.0 mg /L 6-BA +0.2 mg/L NAA,respectively.