| Gynura divaricata DC., a perennial herbage of Compositea, is a kind of wildvegetable which is rich in nutrition. It has the function of reducing bloody sugar as therich flavone in its young stem and leaf have been extrcted and determed. So far,cutting is a main propagation method to this species because it is hardly flowering andfruiting; but it isn't so efficient as to tissue culture. So, it is necessary to establish itsmass clonal propagation technique system for its germ plasm conservation andreproduction. In order to reveal the mechanism and to know the process oforganogenesis, the morphology and AEOs activities have also been studied. The mainresults are as fellows:1. The difference of total flavone contents between stem and leaf of G. divaricata,which were cultivated in both field and pot respectively, has been researched byspectrophotometry. The results show that the linearity of OD510 of rutin, whichcontents range from 0.00μg·mL-1 to 51.352μg·mL-1, is good; r=0.9994; theaverage recovery is 98.36%, and RSD is 1.20% (n=5). The contents of tatal flavone ofthe plant cultivated in field is higher than that in pot; it is higher in the leaf than in thestem; it is also different in different development phases of leaf: 3.338% in the youngleaf, 1.1813% in the mature leaf and 1.338% in the aged leaf.2. In vitro micro-propagation system of G. divaricata has been established. Theculture conditions including basic media, explant typies, inoculation methods andlight intensities etc. have been ptiomized. The best combination of factors and levelsby orthogona design and its repeat tests of the micro-propagation taking young leaf asan explant have been studied. The results are as fellows: the best medium for densecallus inducing is MS(improved)+6-BA 2.0 mg·L-1+NAA 2.0 mg·L-1+KT 0.4mg·L-1+3% Sucrose, for amplification is MS(improved)+6-BA 3.0 mg·L-1+NAA 0.1 mg·L-1+3% Sucrose, and for root inducting is 1/2MS(improved)+NAA0.3 mg·L-1+3% Sucrose. The survial rate of the plantlets is more than 93%. The rapid propgation system of this species has been established: axillary budsproliferating in the medium [MS(improved)+6-BA 1.0 mg·L-1+NAA 0.1 mg·L-1+3% Sucrose], then, cutting with stem and shoot. The rooting rate is above 90%, andthe multiplication coeffecent is at 20.77 in the system.3. The organogenesis of G divaricata has been studied. First, the histologicalchanges of shoots have been observed termly by olefin slice of leaves induced fromthe calli. The results show that the adventitious buds are origined from the calli whichare dedifferentiated from the cells at the edge of leaf cuts. The meristerm nodules andvascular nodeles are occurred when the explantles have been cultured for 15 days;bud primodia, which are origined from the outer calli, having no direct relationshipwith vascular nodel, are occurred after 20～25 days; and the adventitious buds areoccurred after about a month. Second, the development of the adventitious root hasbeen observed by Anatomy method. The results show that adventitious roots comefrom the root inducing primodia which origined from the inter-cambium after 12 days;there are any latent root primodium in the stems of the plantles.The devolopment period from callus induced from leaf to bud can be divided intosix phases. Regulary changes of the activities of SOD, CAT, POP in the period are asfollows:The activities of SOD & POD are going up from the time of callushappenning to the time just before buds occuring, then, dropping down when tinybuds have occured. The CAT activity is falling during the period of inoculation toplenty calli happenning; then, increasing when the tiny buds have come out of thecallus surface; but, decreasing again when the adventitious buds have formed.
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