Tissue Culture Of Astragalus Mongholicus Bunge

Radix Astragali is perennial herb of Leguminosae Papilionoideae plants, with high medicinal values and economic values. Recently, the number of wild plant resourses have become reduced, which can not meet the need of the market because of the excessive collection. Therefore, the rapid propagation has become one of the major messures to increase the quantity.The seeds of Radix Astragali selected from Longxi in Gansu province are used to establish the rapid propagation system in this paper.The steps of the establishment of rapid propagation system contained the sterilization and germination of seeds, the selection of explants, and the selections of callus medium in first and secondary induction, as well as the darkening inhibition medium and rooting medium.The sterilization of seeds and the germination rates of seeds are important to obtain sterile explants. The best sterilizing method were as follows, immersion in detergents for 10min, sterilization with 75% ethanol for 45s and 0.1% HgCl2 for 9.5min. And the rates of germination was 100%, without any pollution. In addtion, the germination rates of seeds in half-a-year and one-year low temperature storage, could obviously increased, with the highest germinatin rate of 100%, if pre-treament was done to immerse the seeds in distilled water for 10 hours.Cotyledon, hypocotyl and radicle of Astragalus mongholicus Bunge were used as explants to induce callus. The results showed that, cotyledon could not induce the callus on MS base medium with any grown regulators, but hypocotyl could induce the callus on MS base medium with 1.0mg/LNAA, that the rate of callus induced by cotyledon was lower with slight darkening, and radicle with higher induction rate but heavier darkening. And the rate of callus induced by cotyledon was the highest, with 70%. Therefore, hypocotyl was the best explant in callus induction.The kinds and proportions of hormone was the key factors in the experiment. The callus induction reached as high as 100% in the combination of 0.5/1.0mg/L6-BA and 0.15mg/L NAA in MS base medium. And in secondary culture, the same medium uesd as in first induction was still good to multiplication of callus. Moreover, Vc was useful in darkening inhibition, and the most effective condition to darkening inhibition was selected, which was as follows, an addition of 0.1mg/L Vc in medium, dark-culturing in the first 3 days, light culturing 10h/d for the rest of days, and with 10-day-generation. For rooting, the best conditin medium was 1/2MS+2.0 mg/L NAA with the highest rate of 83.3%, and there will be more and more roots if 0.3%AC was added.The growth trend of callus of Astragalus mongholicus Bung was tested, that was, the callus of Astragalus mongholicus Bunge could growth well in the 3rd or 4th generation, and multiplication could not occur in the 8th generation.