In vitro culture of different explants from Hylocereus undatus cv.'baiyulong'

Objective Cotyledon,hypocotyl,adventitious bud induction of cotyledonary node,and proliferation of stem section of Hylocereus undatus cv.'baiyulong'were studied to provide technical support for the variety improvement and rapid propagation of it.Method Aseptic seedlings cultured with H.undatus cv.'baiyulong'seeds were materials.Orthogonal design was used to study the effects of culture medium,plant growth regulator concentrations and combinations on adventitious bud induction of cotyledon,hypocotyl,cotyledonary node,stem section proliferation and rooting of H.undatus cv.'baiyulong'.Result The cotyledon,hypocotyl,cotyledonary node of H.undatus cv.'baiyulong'could induce adventitious directly.All the sixteen orthogonal treatments could induce adventitious buds from cotyledonary node with induction rate of 87.1%-100.0%,the optimal medium was WPM+0.50 mg/L TDZ+0.50 mg/L CPPU+0.05 mg/L 6-BA+1.0 mg/L NAA.Only one cotyledon treatment failed to induce adventitious buds,the highest induction rate was 36.0%,and the optimal medium was 1/2MS+0.50 mg/L TDZ+0.05 mg/L CPPU+2.00 mg/L 6-BA+0 mg/L NAA.Only five hypocotyl treatments induced adventitious bud,the highest induction rate was only 3.0%,the optimal medium was 1/2MS+0.05 mg/L TDZ+2.00 mg/L CPPU+1.00 mg/L 6-BA+1.0 mg/L NAA.Removing top of stem section was beneficial to the induction of axillary buds germination,the maximum proliferation coefficient of removing top treatment was 4.2,the maxi-mum proliferation coefficient of keeping top treatment was 3.1.The optimal medium for proliferation culture was WPM+ 0.50 mg/L 6-BA+0.05 mg/L IBA.NAA treatment could promote the rooting of stem section the most suitable medium was 1/2MS+0.10-0.50 mg/L NAA,with the rooting rate of 100.0%.Conclusion Different basic mediums,plant growth regulators,concentrations and their combinations can all induce adventitious buds of cotyledon,hypocotyl,cotyledonary node,proliferation and rooting of stem section of H.undatus cv.'baiyulong'.Cotyledon node is the easiest material to induce adventitious bud,followed by cotyledon,hypocotyl is a difficult material;stem section proliferation and adventitious root induction are easy.