A Study On Tissue Culture And Seed Dormancy Releasing For Buxus Sinica Var. Parvifolia

Buxus sinica var. parvifolia is a kind of fine garden ornamental tree with high value on floriculture. But its resoures have become extinct. In order to protect this plant and satisfy the need of garden, this study is to establish a in vitro culture system and develop a method of releasing seed dormancy for Buxus sinica var. parvifolia for enlarge the resources and put forward it's application.1.The establishment of regeneration system of Buxus sinica var. parvifolia. With the sterilization of explants, the orthogonal experiment designs and multiple compares, the satisfied medium and culture procedure was discussed. The results are listed as follows:(1)Soak the seeds in 30min with 0.1%HgCl2 solution, divest of the seed coat and soak the seeds in in 8min with 0.1%HgCl2 solution, the empoison rate of seed is 5.83%. The stem segments can be sterilized in 3min with 0.1%HgCl2 solution, and then sterilized in 6min with 2%84 solution, the empoison rate of stem was 25.5%. And the survival rate of stem was 74.5%.(2)The best activate medium was MS+2.0mg·L-16-BA+0.5mg·L-1NAA. The inducement rate could be up to 76.4%, and the number of axillary buds was 1.71.(3)The best seasons for drawing materials were April and July. And the empoison rate was low, the survival rate was high in these monthes.(4)The best multiplied medium was MS+2.0mg·L-16-BA+0.1mg·L-1NAA +2.0mg·L-1GA3, and the multiplication rate was 4.28. And the succeed era period was 30d, the succeed era algebra was four era.(5)The best rooting medium was1/2MS+0.1mg/LNAA+20g sucrose, the rooting rate was 73.6%. And the root was strong.(6)The medium with 2/5 ruby mica and 3/5 sand was best for nursling of plantlets. The survival rete of plantlets could be 63.4%.2.Developing a method of seed dormancy for Buxus sinica var. parvifolia. With the comparison of seed biological characteristics, the biological test of germination inhibitory substance in seed coat, the processes of different GA3 concentrations and different sratification periods. The results was as follows:(1)The weight of one thousand seeds was 8.726g, and the vertical diameter was 4.356mm, the transverse diameter was 2.321mm.(2)The permeability of gas was not the main reason of the seed dormancy.(3)The different concentrations of methanol extract from Buxus sinica var. parvifolia seed coat could suppress the germination rate of cabbage seeds.(4)The effective method for the dormancy seed releasing was found as follows, soak the seeds in 200 mg·L-1 GA3 for 48h, stock the seeds with sand under 25℃for 60d, then soak the seeds in 400 mg·L-1 GA3 for 48h;finally, stock the seeds with sand under 0～5℃for 30d.