| Scytosiphon lomentaria (Lyngbye.) Link attach to Phaeophyta, which is widely distributed in the coastal areas from Liaodong Peninsula in the east to Hailing Island of Guangdong Province in the south, and usually grow in collection on bedrocks, stones of mid and low-tide region during April to June. S. lomentaria has a typical cylindrical form and covered by brown mucilaginous layer, always lives in cluster. The length of thallus of S. lomenraria can grow up to20-50cm with diameter of2-5mm in nature, but in artificial culture, the thallus can reach to60-110cm. S. lometaria is characterized by constricted gametophytic erect thalli and sporophytic filament, crustose and cushion-like thalli, which has the life cycle of alternation of heteromorphic generations. Three forms of sporophyte can transform with each other.S. lomentaria is a kind of algae with delicious taste and high nutritional value. Meanwhile, it shows high activity in antioxidant, antitumor, antivirus and antibacterial fields. It has been proved that the extract from S. lomentaria can be put in clinical applications. In addition, as a large alga, S. lomentaria also plays a role in repairing the ecological environment, antifouling and enriching the excess nutrient elements in seawater. Therefore, S. lomentaria is a new type of cultured algae with great potential to develop.The rapid amplification of filaments and sporangia efficient induction are key techniques in S. lomentaria culture. Thus, in this paper, on the premis of understanding the life history and biological characteristics of S. lomentaria, with the germplasm of S. lomentaria preserved by our laboratory, the research of the effect of environmental factors on filaments amplification and sporangia development are put emphasis on. The results can provide theoretical basis and technique support on seeding of S. lomentaria. In addition, the sensitivity of S. lomentaria to commonly used antibiotics were studied in this paper, which supplied theoretical statistics to axenic culture.The results of this thesis were as follows:1. Under the condition setting in the experiment, the optimal temperature, light intensity and photoperiod for filaments of S. lomentaria rapid amplification were22.0℃,72.0μmol/(m2·s) and14L:10D.2. Salinity has significant influence on amplification of filaments of S. lomentaria, a low(16) salinity could cause cell death of filaments of S. lomentaria, while too high(48) could restrain the growth of filaments. Filaments of S. lomentaria got most rapid amplification rate at salinity32.3. Under the condition setting in the experiment, different concentration of NH4+(18.0-54.0mg/L) and NO3-(30.0-90.0mg/L) can be absorbed by the cell of S. lomentaria as the nitrogen source and promote filaments of S. lomentaria growth. But under the condition of same molar concentration of N, NO3-was more conductive to promote filaments amplification than NH4+, and the best concentration of NaNO3was60.0mg/L. Both organic and inorganic phosphorus can be used by filaments of S. lomentaria as the phosphorus source. Under the condition of same molar concentrate of phosphorus, inorganic phosphorus was more conductive to promote filaments amplification, and the optimal concentrate of NaH2PO4was3.0mg/L.4. Three metallic elements (Mn、Mg、Fe) has promoting effects of growth of filaments of S. lomentaria, in which Fe has significant influence on growth of filaments of S. lomentaria. Once Fe element was depleted or insufficient, the cell of filaments turned to green and cytoplasm appeared to be constricted which suggested the filaments were in dysplasia status. The optimal concentrations metallic elements (Mn、Mg、Fe) to promote filaments amplification were0.4、2.0、0.4mg/L.5. Low concentration of vitamin (Vb1、Vb2、Vb12) role in promoting growth of filaments of S. lomentaria, while the high concentration of vitamin shows no toxic effect on cells of filaments of S. lomentaria. Among them, high concentration of Vbi and Vbi2show no effect on the rate of growth of filaments, but the high concentration of Vb2could restrain the growth of filaments. The medium supplemented with appropriate doses of vitamin has positive effect on growth of filaments of S. lomentaria.6. Filaments of S. lomentaria got different growth rate under the condition of different medium. With different medium setting in this experiment, ES medium was most suitable for filaments rapid amplification.7. The requirement of environmental factors during the inducing stage and developing stage of unilocular sporangia in filaments of S.lomentaria is different. High light intensity [>57.6μmol/(m2·s)] is not conductive to formation of unilocular sporangia, and the low light intensity condition is necessary for sporangia inducing.14.4-28.μmol/(m2·s) was the ideal light intensity for sporangia inducing, while28.8-43.μmol/(m2·s) was the optimal light intensity for development of sporangia of S. lomentaria. The most suitable temperature for sporangia inducing was20.0℃and17.0℃was best for the development. Long photoperiod is not conductive to induce and development of sporangia, and10L:14D was the suitable photoperiod for the formation and mature of sporangia. Under the condition of short photoperiod, different photoperiod gradient (6L:18D,8L:16D and10L:14D) showed no promoting effect on development of sporangia.8. Spore releasing of S. lomentaria showed widely adaption to temperature (7.0-27.0℃), but the quantities and the speed of spore releasing differ from temperature. Results showed,12.0℃was the most suitable temperature for spore releasing. Light intensity has significant influence on spore releasing, and72.0μmol/(m2·s) was optimal for spore releasing. A smaller quantity of filament biomass could not meet the requirements of spore-collection, while the excessive quantity of filament biomass could restrain the releasing of the spores.0.8mg/mL was the optimal filament biomass for spore releasing of S. lomentaria.9. The influence of antibiotic on growth and development of sporophyte of S. lomentaria showed that low concentration of Ampicillin (<100μg/mL) and Streptomycin (<100μg/mL) has positive effect on growth of sporophyte of S. lomentaria, while the high concentration (>100μg/mL) could suppress the growth of filaments even cause the death of sporophyte. With different effect of Ampicillin and Streptomycin, low concentration of Kanamycin (10-200μg/mL) showed suppression on growth of filament and cause the death of sporophyte. This effect was exacerbated by the increase of the concentration of Kanamycin. |
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