Establishment Of Tissue Culture And Rapid Propagation Technique For Bletilla Striata

At present,seedling absence has seriously hampered the rapid development of bletilla(Bletilla striata(Thunb.)Reichb.F.)industry.The traditional method of ramets propagation has been far from meeting the technical requirements of bletilla seedling breeding.Therefore,it is essential to explore the technology guiding bletilla seedling breeding.In this thesis,three methods were used to establish bletilla breeding system,including tissue culture,aseptic seeding and direct seeding in greenhouse.Main results and conclusions were shown as follows:1.The rapid propagation system based on Bletilla tissue culture was established:Pseudobulbs of bletilla were sterilized first.Then the following induction treatments were carried out: kryptoblasts were induced on medium with MS + 6-BA(2.5 mg/L)+ NAA(0.1(5.0 mg/L)+ NAA(0.01 mg/L),and the germination rate was 2.50.Germ-free buds were transferred to medium with MS+6-BA(5.0 mg/L)+NAA(0.01 mg/L)for multiplication of clustered buds,and the proliferation multiple was 26.7.Then clustered buds were transferred to medium with MS+6-BA(0.1 mg/L)+NAA(0.1 mg/L)to complete root induction;the rooting rate was 100%,the average number of roots was 6.95 and the average root length was15.0mm;the rooting effect was stable.Finally,the seedlings were transplanted to medium sterilized through 121? high temperature for 30 min,and the survival rate reached 83.33%.2.Bletilla propagation system based on aseptic seeding was established: Two kinds of medium,which were able to cultivate haleness seedlings,were selected out.They both had1/2 MS as the basic medium,and added 30% of coconut juice and 2.0 g / L of peptone respectively.Little seedlings were cultivated on MS for three months to get haleness seedlings for transplant.The refining survival rate was 93% on medium sterilized through 121 ? high temperature for 30 min.The seedling refining survival rates were high also on medium sterilized by 0.1 g/L carbendazim or 0.1 g/L potassium permanganate,and the rates were 89%and 85% respectively.Therefore,those two methods were applicable for medium sterilizationand suitable for large-scale application.3.Bletilla propagation system based on direct seeding in greenhouse was established:Bletilla seeds of good quality were selected and sowed directly in greenhouse.Spraying 1 g/L of potassium permanganate solution controlled bacterial infections effectively.Seeds were sown by 80 mesh sieve screening and the planting density of 1 g/m2;The final average seedling density was 2.50 individuals per square centimeter,and the overall distribution was even.Proper methods of shade,ventilation and mist spray were utilized to keep temperature among 25-35 ? and humidity among 70-90%,in order to obtain normal germination and growth.A 5-10? day-night temperature difference could make bletilla seedlings grow robustly.In addition,spraying 10% of the imidacloprid could effectively prevent and control the damage from the mushroom mosquitoes.In this process,the bacterial infections were rare and the seedling effect was relative ideal.