The Preliminary Study On Tissue Culture Of Sugar Berry

Sugar berry(Celtis laevigata),the small and medium-sized deciduous tree,belongs to the family Ulmaceae,is mainly cultivated in North America and northern Mexico.It is useful and can survive in the harsh environment,especially in salty and drought environment.It is also available for wetland restoration and landscape.Sugar berry is usually germinating by seeds.However,due to long juvenile stage,breeding is low in efficiency.Propagation of elite genotypes by seeds is hard to maintain the elite genotype due to genetic reconstitution.Therefore,development of a rapid vegetative propagation system,has strong practical value in breeding and production.This experiment took the stem-segments with a single bud and hydroponic sprigs as explants.This study included testing different media for in vitro establishment,and collecting materials in different seasons and using shoots produced from hydroponic culture of hardwood branches,media for shoot proliferation,in vitro rooting.We could establish the the aseptic sugar berry culture efficiently.It provided a valuable reference for further study of sugar berry cultivation.The main results of the experiment are following:1.Experimental results of tissue culture and rapid propagation of sugar berry stem segments:(1).The most suitable season for sampling stems of the sugar berry was April,and the disinfection test of stem segment showed that the best sterilization method was:first use the concentration of 70%alcohol for 30s,then the concentration of 10%sodium hypochlorite solution for 10 min,finally inoculated in culture medium containing 0.2%Plant Preservation Mixture.Using this combination,the pollution rate was the lowest,survival rate could reach up to 64.20%.(2).The experiment of axillary bud induction showed that the culture medium and hormone concentration had a significant effect on axillary bud formation.Based on the induction rate and growth of in vitro establishment,the best culture medium formula was DKW+1.5 mg/L 6-BA+0.1 mg/L IBA+0.2%PPM.The axillary buds grew strongly and the leaves were green.(3).The results showed that the concentration of hormone and the type of gelling agent had a certain effect on the proliferation of clustered buds.And the best shoot proliferation medium was MS+2.0 mg/L 6-BA+0.1 mg/L IBA+3g/L gelrite,with a proliferation rate of up to 3.95.The plants grew well and the leaves were green.(4).Compared with MS,the 1/2MS medium was more capable of inducing adventitious bud to root,so the best rooting medium was 1/2MS+0.01 mg/L NAA.The plants grew well with green leaves.2.The results of hydroponic culture and disinfection of sugar berry hardwood cuttings:(1).Hardwood branch hydroponics bud culture:culture medium,strip diameter and hormone type had a significant effect on buds grown by the hydroponics.Hoagland solution can promote dormant branches to break out the buds,with the breakout rate up to 26.83%.After 250 mg/L IBA treatment for 2h,the bud breakout rate of dormant branches was the highest(38.00%).When the diameter of the wood between 0.5 and 0.8 cm,buds not only broke out early,but also had high rate and healthy growth.(2).Disinfection test of the hydroponic buds showed that after 70%alcohol disinfection for 20s,1%sodium hypochlorite disinfection for 10 min,the survival rate could up to 83.33%,and the contamination rate was 7.78%,compared with 1%sodium hypochlorite disinfection for 5min or 15min.