| Dioscorea zingiberensis C. H. Wright of dioscoreaceae is an important medical plant growing only in our country by reason that Diosgenin in its rhizome is one of the most important sources for steroid hormonal medicines, which is called "Pharmacentical Gold" by medical field. In order to find out the efficient path to rapidly propagate D.zingiberensis, optimize the nurture conditions and assortatively breed out the new varieties of polyploid, whose content of sapogenin and biological production may be higher than diploid, the embryonal axis of seedlings, rhizome of the highly content species and leaves, internode segments and protocorms of test-tube seedlings are used as explants in this experiment to induce callus. Consequently, regeneration system was established and complete plants were also produced from callus in differentiation culture. Furthermore, by chemical-inducing mutation, autotetraploid plants were attained. In addition, the protocol for transplanting test-tube plantlet of D.zingiberensis was also discussed in this paper. The following is the major results of this experiment.1. The valid pathway to enhance the germination rate of the seeds of diploid D. zingiberensis was studied and the steri le materials with the satus seedl ings were also gained.The germination rate of seeds was apparently raised by the following means: firstly, we immersed seeds for 15-20 hours in the warm water of 35癈 to soften the seed coat, then, to immerse the seeds for 30 minutes with such hormones as GA3 whose concentration is about 20-50 ppm and finally, when we plant the seeds in fine sands, the germination rate amounted to 62%.A large number of compact calli can be attained with the caulicles of satus seedlings being inoculated to the medium of MS added 6-BA2-4mg/l, and then a large number of plants can also be gotten after subculture.2. The regeneration system of D. zingiberensis has been established and the technical conditions were also been optimized.The explants of leaves, internode segments and protocorms can all be induced to loose calluses on the medium of MS added 2,4-D, but different explants have different rates of induction. The induction rate of leaves is very low, 25% at the best; Internode segments can be induced 50% loose callus on the medium of MS+2,4-D6mg/l, and yet protocorms can be induced above 93% loose calli on the medium of MS+2,4-Dl-6mg/l. However, loose callionly produce a few of regeneration seedlings on differentiation medium and thus, not fit for establishing tachytelic propagation system.The explants from leaves, internode segments, protocorms and caulides can all be induced to compact calli on the medium of MS added 6-B A, but different explants also have different rates of induction. The rates of induction of leaves and internode segments are comparatively low amount to 26.7% and 33.3% respectively; protocorms and caulicles can produce a large number of compact calli on the medium of MS+6-BA2mg/l. And the callus can produce plants whose branches and leaves are flourish on the differentiation medium of MS+6-BA2mg/l+KT0.5mg/l. Splitting branches which cling to protocorms and transplanting them onto the rooting medium of MS+NAA0.5mg/l+IAA0.5mg/l can get a high rooting rate of 87.5%, and transplanting survival rate can get to 53.7%.Our research results indicated that the survival rate of transplanting of test-tube seedlings can be apparently enhanced when add a little of rooting medium to soil.In short, the pathway that the explants of protocorms and caulicles are induced compactcalluses on the medium of MS added 6-BA2mg/l is the most efficient in isolated culturingand rapid propagation of D.zingiberensis.3. Autotetraploid plants were attained through chemical induction.By immersing the compact calluses with contagious buds into 0.05% colchicines for 72 hours, mutation rate of 33,3% were obtained. The muted plants have been proved to be autotetraploid D.zingiberensis with fine traits through cytology identification and field culti...
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