Study On In Vitro Culture And Rapid Propagation Of Dendrobium Wardianum

The paper took the seeds of Dendrobium. wardianum as research objects. This thesis had a systematic research on the embryo culture and rapid propagation. It was laid the foundation for the preservation of genetic resources and rapid propagation system establishment.The results showed that the best pollination time of the female flower(mother) was after blooming of 1 day when not only would the capsule setting rate be reached 80.95% but the plump seed ratio be reached 90.73%.Seeds of Den. wardianum cultured on the media of B5 +Sugar20 g?L-1 + CW20 % + pH 5.4 for 50 days and the germination rate was reached 79%. The optimal differentiation medium of protocorm from former stage was Hyponex No.1 3 g?L-1+Peptone 2 g?L-1+NAA 0.2 mg?L-1+CW 10% + Potato extract 10%+Plucose 20 g?L-1+pH5.6 and the protocorm was cultured 70 days. The proliferation medium for adventitious buds was CHB+ NAA 0.5 + 6-BA 0.2+CW10%+Sugar 30g?L-1 +pH 5.8.It was 150 days for this culture stage and the multiplication coefficient was 6.68.The aseptic seedling which obtained from the former culture stage were cultured on the root induction media of Hyponex No.2 3g?L-1+ Peptone 2 g?L-1 +IBA1 mg?L-1+ CW 10%+ Sugar 30 g?L-1 +pH 5.6 for 45 days ,with the rooting rate at 100%,and the average root number of 2.3. The last stage of in vitro was strong plantlets and rootage. The optimal medium was Hyponex No.1 3 g?L-1+ Peptone 2 g?L-1 +Sugar 30 g?L-1 + Activated carbon 1 g?L-1+pH 5.6. 90 days later the plantlets were hardening-seedling and transplanting in the materials mixed pine bark with perlite and orchid matrix, ,with the survival rate at 92%.The culture substrate was sterilized with high pressure steam(121℃, 120 min).Aseptic seedling with strong growth vigor and 2㎝ height was adopted for the PLBs induction materials. Shoot segments with 1-2 nodes were excised from Den. wardianum plants raised in vitro. The segments were cultured on the media of 1/2MS+2.4-D 0.2 mg?L-1+Sugar 30g?L-1+pH 5.8 for 20 days.When the shoot bud diameter reached to 1.2-1.5㎜, it must be detached and transferred to the same media for 15-20 days.Then the PLBs subcultured on 1/2MS+NAA 1 mg?L-1+CW10%+Sugar 30 g?L-1 +pH 5.6 for proliferation with the proliferation rate at 7.33.The PLBs transferred to the 1/2MS media within 25-30 days.The optimal PLBs differentiation medium was 1/2MS+NAA 0.5 mg?L-1+Sugar 30 g?L-1+CW 10%+pH 5.6.