| Sempervivum tectorum is a perennial succulent ornamental plant that spread widely in Europe. Its fleshy leaves have both pharmaceutical and health functions, the substance extracted from it can cure some skin diseases( such as faucitis, stomatitis, bronchitis, burn, scald, bite and sting, etc. ) and be helpful for skin nourishing, liver protection, furthermore, it can refresh oneself with it as tea. To establish the rapid propagation system, the fleshy leaves as explants were cultured in vitro. Researches on its in vitro culture, plantlets regeneration, characters of physiology and biochemistry and the histology of morphogenesis were conducted on the current paper. The results are as follows:1. Optimal mediums for Sempervivum tectorum in vitro propagation and the clone system were established. The research shows that the phytohormone is the key element for morphogenesis of in vitro culture.1.1 Callus can be induced on the medium added with 6-BA and 2,4-D and the medium added with 6-BA combined with NAA and IAA. However callus formed on the former medium is loosen than that on the latter one. The former is more difficult for bud differentiation whereas the latter is denser and it's easier for bud differentiation.1.2 Plantlets formed from the calli, which is induced from the fleshy leaves cultured on the medium added 2,4-D combined with 6-BA and the medium added with 6-BA 1 mg/L, NAA 1 mg/L and IAA 1 mg/L, after that transferred to the medium added with 6-BA 1 mg/L + NAA 1 mg/L or 6-BA, in a organogeny-type morphogenesis way.1.3 Plantlets can be induced directly from the cultured explants on the medium added with 6-BA 2 ml/L + NAA 0.2 ml/L, in a organ-type morphogenesis way. The GA3 added addictively on medium can shorten the duration of buds formation.1.4 1/2MS medium combining with NAA and IAA was optimum for rooting of plantlets, the active charcoal was also propitious to that. And rapid propagation system with high reproductive coefficient and reproductive rate was established.2. Research on vitrification during the in vitro culture of Sempervivum tectorum was proceed.The results suggested that vitrification can be effectively controlled by strengthening the illumination, reducing the inorganic salt content (to use 1/2MS medium), decreasing the temperature, inducing the content of the saccharose and agar, even adding of antibiotic.3. Anatomic structures of Sempervivum tectorum leaf.The Sempervivum tectorum is a typical xerophil, its leaves are characterized with cutin, density gland hair, and the stoma was composed with two kidney safeguard cells and two hook convoy cells, which effectively control the evaporation. The leaf anatomic structure indicated that mesophyll was without the differentiation of palisade and sponge tissue. And the mesophyll cell is large and function as water storage. The vascular bundles distribute parallel; trachea and sieve tube were small and wrapped with vascular sheath.4. Characters of physiology and biochemistry of Sempervivum tectorum in vitro cultureDuring the morphogenesis in organogeny way, the explants expanded and turned green initially, and embryonic cell lump formed on the surface of explants, and then grew into plantlet. The results indicated that all the testing indexes were increased during the formation of the organ in culture and did not reduce until the organ formed. In terms of the curve, the content of protein, amino acid, nucleic acid, soluble sugar, amylum and the bioaction of proteinase, mylase, peroxidase both changed consistent with the morphogenesis of this approach.5. Close relationships between the change of the characters of physiology and biochemistry and different development phase of organogeny-type morphogenesis approaches.The calli may be induced when the contents of protein, amino acid, nucleic acid, soluble sugar(dry-weight), were relatively higher, whereas the contents of amylum, Vc were relatively lower. During callus accretion the contents of protein, were relatively lower, whereas the contents amino acid, nucleic ac... |
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