Construction Of Rapid Propagation System And Polyploid Induction Of Dendrobium Wardiamum

Dendrobium possess high medicinal value and ornamental value. In recent years, the wild Dendrobium resources are dramatically decreased as the result of habitat deterioration and unreasonable excavation of mankind, most of them are endangered. Moreover, with the improvement of living standard and appreciation ability of human beings, there are an increasing requirement for flowers with diversity, ornamental value and cultivation characteristic. Nowadays, the widely cultivated ornamental Dendrobium are mainly selected and bred from the hybrid of initial species. While research on breeding of Dendrobium in China is behind that in western countries, only few scholars focus on the cross breeding and ploidy breeding. Therefore, D. wardianum, which possesses high ornamental and medicinal values, was selected as research materials, and its adaptability and biological characteristics in Fu-zhou was observed and documented, tissue culture and polyploidy breeding was also researched, hoping to offer theoretical basis and practical basisdatum for the protection, development, utilization of Dendrobium resources and its germplasm innovation. The major results were as followed:1. The florescence of D. wardiamum was during April to May, the Single-flowered longevity could reach 15 to 20 days. The pseudobulb decomposed seriously due to the hot and humid climate during the July to August, but the damage was slighter in dense forest. Breeding system experiments showed that D. wardiamum were highly self-compatible, and there wes no automatic self pollination. Artificial pollination indicated that 85.71% fruit set by self-pollination,76.67% by geitonogamous pollination, and 84.21% by xenogamous pollination. The seed viability of different pollination methods tested by 2,3,5-triphenyltetrazolium chloride(TTC) had large difference. The viability of geitonogamous pollination embryos and xenogamous pollination embryos were high, the viability rate reached 55.99% and 51.55%, respectively. The viability of self-pollination embryos and pollinator pollination embryos were only 3.94% and 0.00%, respectively. Compared with TTC method, the germination method had the same result, but the value was higher. The germination rate of geitonogamous pollination, xenogamous pollination, self-pollination and pollinator pollination were 60.73%,57.60%,4% and 1.27%, respectively.2. The results indicated that:the optimum medium for the embryo germination and enlargement was 1/2 MS+IBA 1.0 mg L-1+6-BA 1.0 mg·L-1+NAA 2.0 mg·L-1+banana mud 50 g·L-1 with the germination rate of 91.29%. The optimum medium for differentiation was 1/2 MS+IBA 0.5 mg-L"’+6-BA 1.0 mg·L-1+NAA 0.5 mg·L-1+banana mud 50 g·L-1. The optimum medium for dry matter accumulation was 1/2 MS+IBA 2.0 mg-L"’+6-BA 2.0 mg·L-1+NAA 0.5 mg·L-1+banana mud 200 g·L-1. The optimum medium for proliferation of cluster buds was 1/2 MS+IBA 0.5 mg·L-1 +6-BA 1.0 mg·L-1+NAA 0.5 mg·L-1+banana mud 100 g·L-1 with the average proliferation rate of 6.33. The optimum medium for rooting was 1/2 MS+IBA 0.5 mg·L-1+6-BA 3.0 mg·L-1+NAA 0.2 mg·L-1+banana mud 50 g·L-1+mashed potato 50 g·L-1.3. The results of the study on adventitious bud induction and PLBs suspension culture showed that:the optimum medium for induction and proliferation of adventitious bud was 1/2MS+NAA0.5mg·L-1+IBA0.2mg-L-1+6-BA2.0 mg-L-1+KT 1.0 mg·L-1, the multiplication coefficients and induction rate reached 5.07 and 100% respectively, and the optimum basic medium was TH with the the multiplication coefficients and induction rate of 6 and 100%. The optimum basic medium for suspension culture were B5 and MS, the multiplication coefficients reached 4.310 and 4.028 respectively, and the content of polysaccharide were 7.08% and 7.12%. Additive with banana mud and coconut juice, the propagation coefficient and the polysaccharide content were the highest, respectively reached 3.91 and 9.97%; The optimum hormone combinations was NAA0.5 mg-L-1+6-BA0.2mg·L-1.4. The result indicated that the materials were soaked at 0.1% colchicines solution for 12 h reached to the highest inducing ratio and lowest death rate, and some 26.0% variant plant were discovered. The treatment of adding 0.03% colchicines in the medium acquired the best inductive effect, the variant plant was up to 34.0%. The longer the treatment time and the higher the concentration of colchicine were, the stronger side-effects were. Compared with immersing explants, the side-effects were more serious and lasted longer by adding colchicines in medium, the death rate was still high in subculture.There are obvious differences between polyploid and diploid plant. The morphology of polyploid showed the following features:its stems were thick and short; leaves were wide and thick; the internodes were short. The stomata and guard cells diameter were increased, and the number of stomata per unit leaf area of the leaf was obviously reduced. The chromosome numbers of diploid cell was 2n=2x=38, while teraploid cells was 2n=4x=76.