| The genus Zelkova, belongs to family Ulmaceae, has 10 spicies, of which 3 distribute in China. They are Zelkova schneideriana Hand. -Mazz., Z. Serrrata(Thunb.) Makino and Z sinica Schneid. Among them, Z. schneideriana is not only a broad-leaf hard-wood species, but also a high-value one for gardening. Due to its high quality with beautiful veins, and physical properties in timber, Z schneideriana is popular in both international and domestical market for indoors' decoration, furniture making, as well as for architectures and vehicles' making. Becused of uncontrolled commercial logging, Zelkova is now an endengour spicies and listed in 2nd class in the red book of endengour spicies in Chian.Up to now, there was no systematic research work on Zelkova reported, and only morphology describing, basical biological peroperties, sivilculture, nurses techniques contucted.. It is important to conduct a systematic studies on its ecology, and genetics, cell biology, and microprogate technology of Z. schneideeriana on the level of molecule and cell engineering, which can provide theory and technology for plant cell engineering and contemporarily provide industrialization technology for protecting and plantation the Zelkova recourses in China.Z,. schneideriana, Z. serrata and Z. sinica Schneid were the research material in our work. We developed a technology of tissue culture and regenerating saplings, observed and analyzed the process of cell splitting, chromosome characters of plants, callus and regenerated plant.. RAPD was applied to analyze the differences under DNA level among Zelkova plants, callus and regenerated saplings. The incompact callus was used to conduct cell suspension culture and then the cell-suspend-system and its dynamic was set up and studied. The conformation process of the culture callus and regenerated plantlet was analyzed.The results showed that there were distinct differences in characteristics of both morphology and biology among the three Zelkova species distributed in China, such as trunk color, leaf quality and shape, winter buds and their fruit shape and size, etc. Leaf-area coefficient had direct correlation with leaf morphology. Z. schneideriana Hand.-Mazz. and Z. serrata(Thunb.) Makino have a acuminate leaf with leaf-area coefficient of 0.735 and 0.728, while Z. sinica Schneid was trail-tine shaped leaf, with coefficient of 0.714. The leaf of Zelkova schneideriana was thiner than those of others . The weight of per-thousand-seed was 26.89g of Z. sinica Schneid, 15.86g of Z. schneideriana Hand.-Mazz and and 13.30g of Z. serrata (Thunb.), respectively.The cell of the three species was typical karyokinesis. Although they had the same chromosome number of 28, the build up of chromosome type were different. The formula of chromosome type wereas followed: Z.schneideriana 2n = 2x = 28 = 7m + 7sm; Z serrata 2n = 2x = 28 =13m +1sm; Z sinica 2n = 2x = 28 = 10m +4sm. Furthermore, the differences of their DNA build up could be distinguished immediately form the DNA extraction by improved CTAB method and by 8 primers which were screened out from 180 primers.WPM was the optimum media for inducting callus , subculture and regenerate of plant on Zelkova schneideriana. Induction and subculture of callus of Zelkova schneideriana was affected by sorts of auxin, its concentration, the source and season of the explant collection, illumination intensity and pH, etc. PVP and AgNO3 were effective to restrain browning of callus, and Vc had less effectiveness while active carbon had no effect.Regeneration plantlet was obtained from ex-plant of stem and mature embryo by means of direct organ-developing.. At first, a , bud developed from the explant and then an integrity saplings occurred by root inducement. The young stem of seedlings developed cluster buds on WPM+1.0 mg.L-1BA media, and mature embryo did so on WPM+2.0 mg.L-1BA+1.0 mg.L-1NAA media; the bourgeon of mature tree developed side buds on MS+3.0 mg.L-1BA media. The other explant such as cotyledon, hypocotyls, leaf, top-bud and stem, etc., devel...
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