Study On Micropropagation Technique Of Rare And Wild Plant With Extremely Small Population

The populations and distribution range of the rare and wild plant with extremely small population are diminishing nowadays because of poor reproductive ability and human activity.The conservation and sustainable utilization of rare and endangered wild plant with extremely small population is one of the important research topics of the current conservation biology.To accomplish this goal,a large number of seedlings are needed for ex-situ conservation and reintroduction.However,the reproduction of the rare wild plant with extremely small population is difficult.In this paper,Euryodendron excelsum H.T.Chang,Acer catalpifolium Rehder,Sophora tomentosa L.,Hemiboea subacaulis Hand.-Mazz were respectively studied to establish tissue culture and rapid propagation system,which are useful for their conservation and utilization,and will also provide a reference for the conservation and utilization of other rare and endangered plants.The results were listed as follows:1.Tissue culture of Euryodendron excelsum H.T.Chang : June or October was the best period for explant collection,the induction rate dormant bud rate of stem in June is 52.22%,and 51.11% in October.The optimal disinfection method for Euryodendron excelsum H.T.Chang was using 0.1% mercuric chloride for 18 minutes.WPM + KT 5.0 mg/L + NAA 0.1 mg/L were optimal for inducing axillary bud,WPM medium contained 1.0 mg/L BA with 0.1 mg/L NAA was suitable for cluster multiplication,and the proliferation rate was 1.83,WPM + BA 0.1 mg/L + NAA 0.1 mg/L was suitable for cluster multiplication of seedlings from seeds,and the proliferation rate was 2.00;The optimal sub-culture period is about 60 days,multiplication and the proliferation rate is 2.33;Rooting of the shoots in vitro was diffcult and no rooting plantlet was attained in all the media for root inducing.2.Tissue culture of Acer catalpifolium Rehder : The optimal disinfection method for aseptic seeding was using 0.1% mercuric chloride for 9 minutes;MS + BA 1.5 mg/L + NAA 0.2 mg/L was best treatment for germination;The leaf base segment was optimal part for callus induction and the optimal medium was MS + 2.0 mg/L 2,4-D,the callus inducing rate was 78.89%.The H medium with 0.015 mg/L TDZ and 0.05 mg/L NAA was optimal for shoot multiplication,and the multiplication coefficient is 2.22;All shoots rooted in the MS medium without plant growth regulator.3.Tissue culture of Sophora tomentosa L.: The optimal disinfection method for stem of Sophora tomentosa L.was using 0.1% mercuric chloride for 18 minutes,and 100% explants survied;1/2MS medium combined 1.0 mg/L BA with 0.25 mg/L 2ip was optimal medium for adventitious buds induction;WPM was optimal basic medium and the optimal BA concentration was 1.0 mg/L;The optimal sucrose concentration was 20 g/L,which were best for multiplication of adventitious buds,the optimal culture period is about 50 days.Rooting rate was 30.00% on WPM + 1.0 mg/L NAA,however,the roots regenerated were abnormal and,there was not survival plantlets in vitro in transplanting.4.Tissue culture of Hemiboea subacaulis Hand.-Mazz : The leaves of Hemiboea subacaulis from greenhouse were sterilized by immersion in 0.1% mercuric chloride for 9 minutes was optimal disinfection method.The highest inducing rate of adventitious buds was 19.75 on MS medium with 1.5 mg/L BA and 0.1 mg/L NAA in cultured 30-day culture;The MS medium with 2.0 mg/L BA and 0.1 mg/L NAA was optimal for shoot multiplication;The most suitable rooting medium was on MS medium with 1.0 mg/L NAA.By overall consideration form shoot length,numbers and length of root,and the rooting rate was 100%.The MS liquid medium with Vermiculite as support and supplemented 0.1 mg/L IBA was best treatment for rooting induction,the rooting rate was also 100%,and the roots had better quality than on MS solid medium.90% of plantlets in vitro regenerated survived following acclimatization on peat.