Study On Tissue Culture And Rapid Propagation System Of The Third Generation Chinese Fir Clones

Chinese fir（Cunninghamia lanceolate）is a unique timber tree species in China,which is widely distributed and its output wood accounts for about 25%of the national commodity timber.With the increase of demand for timber and the enhancement of the awareness of improved varieties throughout the country,the requirements for the productivity and quality of Chinese fir are also raised accordingly.In order to make up for the lack of the research of high-generation Chinese fir in Sichuan Province,and to preserve and propagate the excellent species,tissue culture experiment of the third generation of Chinese fir was carried out in this study.The materials were selected from the third generation seed orchard of Chinese fir in Sichuan Province,aiming to establish a stable Rapid Propagation System,which solved the problem of selection of sampling time,sterilization of explants,induction of adventitious buds,induction of adventitious roots,transplanting of plantlets in tissue culture and so on.And constructed the model according to the results.Major research results are as follows.1.The best time for collecting the shoot segment explants of Chinese fir is in Mid-March,followed by mid-may,with the worst effect in mid-october.2.The best disinfection scheme of Chinese fir’s stem explants:1%detergent water soak for 30 min,rinse under running water for 3-4 h,0.1%carbendazim soak for 30min.After washing,placed in the laminar flow cabinet,then disinfected by immersion in 70%alcohol twice for 15 s each time,washed with aseptic water for 3 times after each immersion,then immersion in 0.1%HgCl₂ twice for 4 minutes each time,and washed with aseptic water for 5 times after each immersion.The pollution rate and mortality rate can be controlled at 28.9%and 13.1%respectively.3.The optimal medium for adventitious bud proliferation of Chinese fir:1/2 MS+0.8 mg/L 6-BA+0.6 mg/L IBA+0.1 mg/L NAA,the average number of multiplication buds is 5.4,model:y（bud proliferation number）=0.550+6.267x（6-BA）.The most suitable growth medium for seedling height of Chinese fir is:arbitrary four media+0.8 mg/L 6-BA+0.6 mg/L IBA+0.3 mg/L NAA,the average plant height is3.0 to 3.9 cm.Model:y（seeding height）=0.581+2.607x₁（IBA）+3.217x₂（NAA）+1.298x₃（6-BA）+0.132x₄（medium）.The optimal medium for inducing root number of Chinese fir:1/4 MS+1.2 mg/L IBA+0.4 mg/L NAA+20 g/L sucrose,under this condition,the average number of roots is 6,model:y（rooting number）=25.98-79.05x+86.92x²-29.17x³（x:IBA）.The optimal medium for root growth is:WPM+1.5 mg/L IBA+0 mg/L NAA+30 g/L sucrose,average root length above 6 cm,model:y（root length）=3.633-4.030x₁（NAA）+0.124x₂（sucrose）.4.Tissue culture seedling transplanting:the volume ratio of loess to perlite to vermiculite is 3:3:1,the culture temperature is 21-26°C and the humidity is 60-80%,then the survival rate of transplanting could reached 65%.