Screening And Evaluation Of Chemical Mutagenesis Plant Of Desmodium Styracifolium (Osbeck) Merr.

Desmodium styracifolium is originated from dried aerial parts of D. styracifolium in Family Leguminosae. With the effects of disinhibiting dampness and relieving jaundice, promoting diuresis and relieving stranguria, D. styracifolium was usually applied for the treatment of jaundice, red urine, heat stranguria, urolithiasis, difficulty and pain in micturition, edema oliguria and so on. With the widely application of D. styracifolium, its consumption is increasing and wild resources cannot meet the market demands. Increased the planting area and enlarge the scale of artificial cultivation is the effective way to alleviate supply and demand contradiction. Screening excellent breed and improving the quality of medicinal materials and production is another problem to be solved. In this paper D. styracifolium seeds were soaked in Na N3, EMS and colchicine respectively, and the effects of chemical mutagenesis on seed germination, agronomic characters, physiological property, medicinal materials quality and yield, genetic polymorphism were evaluated. The main research results were summarized as follows:1. Na N3 could reduce the germination rate, germination potential and inhibit the growth of root and hypocotyl of D. styracifolium seeds. EMS significantly decreased seed germination rate, the inhibition varies with time and increases with the increase of concentration, EMS has significant effects on seed root length, inhibits the growth of hypocotyl. After soaked in colchicine, it appeared three types, such as inflated stem and long root, inflated stem and short root and stem with the head inflated treatment group. Soaked in 15 g/L Na N3 for 3 h, 15 g/L EMS for 8 h or 1.0 g/L colchicine for 16 h could be the optimum dosage.2. This test obtained 9 types of 13 D. styracifolium variation plants, such as dwarf plant(V-1, V-6, V-10), seedlings branch plant(V-2, V-11), thick ground diameter plant(V-3, V-8), long plant height(V-12), more branches plant(V-5), more branches,internodes short and dwarf plant(V-4), seedlings branch and thick ground diameter plant(V-7), long plant height and thick ground diameter plant(V-9), long plant height, thick ground diameter and more branches plant(V-13). The induction rate of Na N3, EMS and colchicine respectively was 5%, 4%, 4%.3. Chemical mutagen leaded to membrane lipid peroxidation of D.styracifolium, and promoted the leaf soluble sugar and MDA content accumulation, and it could reduce cell osmotic potential to save water to resist stress damage. Na N3, EMS and colchicine were significantly effect on leaf soluble protein content and POD, SOD activity, compared with control have increased and decreased, the possible reasons as follows: the activities of plant to a certain extent of damage, but still within the scope of the regulation; reduced activity to the damage will eventually broke the metabolic balance, and enzyme activity was irreversible decline, and the ability of scavenging free radicals decreased and dynamic balance disordered, then causing irreversible damage.4. Chemical mutagenesis had significantly influence on chemical components(total flavonoids, total polysaccharides, schaftoside) content and medicinal material yield of Desmodium styracifolium, and it could be a method to obtain high quality and high yield breeding Desmodium styracifolium. V-4 plant’s leaves and stems total flavonoids content were the highest, respectively is 43.73 mg/g and 24.50 mg/g. V-10 plant’s leaf total polysaccharide content in the highest, reached 14.38 mg/g. V-2 plant’s stem total polysaccharide content was 25.40 mg/g; V-4 plant’s leaf schaftoside content is the highest, reached 0.74% and V-1 plant’s leaf schaftoside content is 0.133%. Comprehensive consideration, V-4 plant’s seeds can be used as a wide selection of high quality materials. V-2, V-3, V-5, V-7, V-9, V-13 plants’ output is far higher than control group, its seeds can be used as breeding high yield materials.5. Mutagenic treatment leaded significant difference on the molecular level of D. styracifolium. Mutagenic plants’ SRAP molecular markers analysis polymorphism ratio was extremely high, reached 96.45%. Cluster analysis tree results showed that the molecular moisture variation in size order was V-13 > V-7> V-6> V-11> V-10> V-12> V-9> V-8> V-4> V-5> V-3> V-2> V-1, and the effect on Na N3 was little than EMS and colchicine.