The Establishment In Vitro Regeneration System Of Toona Ciliata

As national secondary endangered protective plants, Toona ciliata is the main tree species of precious tree plantation in southern China. The production of its seedlings can provide the foundation for T. ciliata plantation’s steady development. The aim of this research is to explore T. ciliate seedling’s large-scale production and address the issue of seedling’s shortage in its plantation procedure. In this research, the researcher chose the superior Toona ciliata single plants as materials. The stem segment of T. ciliate was used as explants. Both orthogonal experiment design and complete randomized design as well as range analysis, analysis of variance and multiple comparisons were used in this research. Disinfection of explants, primary culture, subculture, rooting and the seedling transplants were studied. The results are as follows:1) The best time for collecting the stem segment explants of T. ciliate is in spring or early summer, around March to June. During this period, the contamination rate which comes from the stem segment explants’ disinfection was greatly reduced.2) Firstly, stem segments were soaked with 1% detergent water for lOmin; then rinse the stem segments under running water for 3h after scrubbing; soak the stem segments with 0.1% carbendazim for 30min before sterilization. Finally, disinfected by 75% ethanol for 20s and immersed with 0.1% HgCl2 for 8min before inoculating. By this way, the contamination rate can be decreased to 27.21% and the survival rate can reach 57.86%, which can meet the needs of its primary culture.3) MS was the best basal medium, which adds 0.5mg/L 6-BA and 0.01mg/L NAA, the initiation rate reached 72.17%, and the average bud shoot height is 3.47cm.4) Optimal mediums in subculture multiplication is MS+6-BA 1.4mg/L+NAA 0.02 mg/L+GA31.0 mg/L, and the average rate reached 4.70 per generation, and the average bud shoot height is 4.27cm. Meanwhile, vitrification on cluster buds was improved effectively.5) The suitable medium for rooting of plantlets was 1/2MS(1/4MS)+ IBA O.lmg/L+NAA 0.01mg/L, in which the rooting rate could be up to 76.46%, the number of roots was 6.37and the rooting length reached 8.33cm.6) Transplanted T. ciliate in vitro seeding on the optimal ground, and the volume ratio of yellow soil to river sand to vermiculite is 2:1:1.Then the survival rate of transplanting could reach 70%.To sum up, the studies on the establishment in vitro regeneration system of T. ciliata could not only realize its seedling large-scale production but also provide the technical basis for T. ciliata quality seedlings factory production, thus to promote the development of its plantation.