Studies On Rapid Propagation And Polyploid Breeding Of Withania Somnifera (L.) Dunal

Withania somnifera (L.) Dunal, plants of Withania in the Solanaceae family, can be found growing in India,South Africa,Pakistans and other places. The plant mainly has been used as an aphrodisia and liver tonic. Its activity in antibacterial,inflammation,cytotoxin,cellular immunitys and so on. A new study found that its activity in anti-cancer and radiation sensitizing. In addition, the Withania somnifera contains a lot of iron, can be used for anemia, its market prospects are very large with it used in the health and the application of medicine.At present, research about Withania somnifera were focused in its pharmacological applications, and the research about raising its medicinal ingredients by change their ploidy is still blank. In this study, Plant tissue culture and colchicines induction technology were applied. Firstly, to established rapid propagation system of Withania somnifera in vitro, provide theoretical support for industrial production for the nursery. Secondary,explore the optimum conditions to obtained tetraploid by colchicines induction technology. It is the bases of the research that ploidy breeding of Withania somnifera and to obtained single higher medicinal ingredients polyploid new germplasm.The result of rapid propagation research shows: The explants were dipped in the scour 10 minutes and washen 30min by tap water, then sterilized 15 seconds by 75% alcohol and 13min by 0.1% HgCl₂, rinsed 4-6 times by sterilized water. The appropriate medium for inducing buds from explants was MS+1.0mg/L 6-BA +0.2mg/L NAA, induction rate was 100% and mean of buds was 4.4. The best of multiplication medium was MS+0.5mg/L 6-BA+0.05mg/L NAA, multiplication coefficient reached 5.5. The best rooting medium was l/2MS+0.2mg/L IBA, the states of plantlets and roots were good. The induction rate was 100%, The surviving rate of plantlets was above 95% after transplanted to the ground.The inducing polyploid of Withania somnifera was carried out by immersing buds with colchicines. The result indicated that: It was the most effectively induced by immersing buds in 0.5% colchicine solution for 48h, which had the most tetraploid plantlets, inductive frequency was 13.79%. The leaf, stoma, guard cell characteristics of tetraploids and diploids Withania somnifera were compared. The result indicated that tetraploids leaves were thicker, but shorter and with lower leaf index. The thickness leaves of tetraploids were 162.7% of the diploids respectively; the length of leaves of tetraploids were 73.1% of the diploids respectively. The tetraploids with fewer stoma densities which were 55.83% of the diploids respectively, with bigger guard cells. The guard cells' length of tetraploids were 171.72% of the diploids respectively. The numbers of their chloroplast in the guard cells increased evidently and there were 188.87% of the diploids respectively.The tetraploid plantlets and diploid plantlets of Withania somnifera were carried out the low-temperature treatment, then their exosmosis rates of electrolyte and rates of damage of cytomembrane were compared. Under the same temperature, the electrolyte exosmosis rate and damage of cytomembrane of tetraploid plants were lower than diploid plants. It shows that the tetraploid Withania somnifera's cold resistance and anti-drought are stronger than these of diploid Withania somnifera.