| Scytosiphon lomentaria (Lyngbye.) Link attach to Phaeophyta, which is widelydistributed in the coastal areas from Liaodong Peninsula in the north to Hailing Islandof Guangdong Province in the south.The heteromorphic generations of S. lomentariacomposed of macroscopic erect gametophytes and microscopic sporophytes. Themature thalli of S. lomentaria are erect, cylindrical, tubular and constricted, up to15-70cm long and3-10mm wide. S. lomentaria is popular around coastal residents inChina, Japan and Korea, because of its delicious tastes, good mouthfeel and highnutritional value. Meanwhile, S. lomentaria also has a high medical value with highactivity in antioxidant, antitumor, antivirus and antibacterial aspects. In addition, S.lomentaria also plays an important role in ecological remediation, antifouling andremoving the excess nutrient elements in seawater. Taken together, S. lomentaria is apotential algal resource with promising perspective involved in high utilization valuein the near future.The sporophytes of S. lomentaria are the object of germplasm preservation,while the gametophytes are the object of cultivation. The spores released bysporophytes turn into mature frond which has a great economic value after a series ofdevelopment. Thus,in this paper, on the basis of preliminary study of the life historyof S. lomentaria, regarding spore and young gametophyte of S. lomentaria asexperimental subjects, the development process of gametophyte is recordedcontinuously and the research of the effects of environmental factors on sporeattachment, germination and the growth of young gametophyte are put emphasis on.The results would provide theoretical basis and technique support on sporelingsdevelopment in factory of S. lomentaria. In addition, ultrastructure of the filament ofS. lomentaria was also observed with the transmission electron microscopy in thispaper, which aims to accumulate initial material for the cytology study of S.lomentaria. The results were as follows:1. The development of gametophyte of S.lomentaria was divided into fivephases: spore attachment, spore germination, cell division, holdfast generating, erectsporelings producing and development of sporelings. Meanwhile, morphologicalfeatures of each phase of gametophyte development were described in detail. Theresults showed that many sprouts could form on the surface of the holdfast, with theresult that one gametophyte has more sporelings instead of one. In addition, we alsofound that synechia would form between contiguous holdfasts after its formation.2. Light intensity, temperature, salinity and pH all have an obvious significanceon spore attachment of S. lomentaria.(1) The optimal light intensity for sporeattachment was found at54μmol/(m2·s), at which the attachment amount per unit areawas the highest.(2)7-22℃was the appropriate temperature for spore attachment and19℃was the most suitable temperature for spore attachment, higher temperaturewould reduce the swimming ability of spores.(3) The optimal salinity for sporeattachment was30and spore of S. lomentaria would die under the condition of lowersalinity (≤24) and higher salinity (≧40).(4) Within6.7-9.7of pH, there was justdifferent in quantity of attached spores, but no distinction in spore activity,8.2was themost suitable pH for spore attachment.3. Light intensity was the necessary condition for spore germination. Spores ofS.lomentaria would germinate within18-126μ mol/(m2s). The optimal lightintensity for spore attachment was found at54μmol/(m2·s), while the sporegermination would be inhibited even be killed at higher light intensity[≥108μmol/(m2·s）]. Cell division of young gametophytes showed widely adaption to lightintensity[18-126μ mol/(m2s）], but the speed of cell devision differ with lightintensity,54μmol/(m2·s） was the ideal light intensity for cell division.4. Temperature has an significant influence on spore germination and celldivision.6-15℃was the optimal temperature for spore germination, they had similarquantity of germination, however in this range, the higher temperature the higher speed of germination.12℃was the most suitable temperature for the earlydevelopment of gametophytes, at which holdfast produced firstly.5. Sporelings of S.lomentaria could develop well under the condition of9-90μ mol/(m2s）, but it showed different relative growth of body length (RGR) atdifferent light intensity. The best light intensity for the growth of sporelings was36μmol/(m2·s）. While the growth of sporelings would be suppressed at higher lightintensity[≥108）μ mol/(m2s)], at which the plasmolysis of cells of sporelings wouldhappen even caused the breakage of gametophytes.6. Temperature has a significant influence on the growth of sporelings ofS.lomentaria.6-12℃was the appropriate temperature for the growth of sporelings,but there would have the longest length of sporelings under the condition of12℃,which is the most suitable temperature for development of sporelings, While the RGRhad a tendency to increase gradually with the growth of gametophytes at6℃. Inaddition, higher temperature (≥15℃) could damage sporelings, with themanifestation that atrophy of sporelings and breskage of sporelings even the death ofgametophytes. The damage was exacerbated by the increase of the temperature.7. Ultrastructure of filaments of S. lomentaria was observed by transmissionelectron microscope which gave us a clear vision of the ultrastructure of the importantorganelle in cell, for example,cell nucleus, cell wall, chloroplast, pyrenoid,mitochondria and golgi body. Results showed that cells of S.lomentaria had morethylakoids than cells of other phaeophytes. This indicated the strong photosynthesisability of S.lomentaria. In addition, the electron micrograph showed plenty ofphysodes secreted by golgi body, proved that filaments of S. lomentaria had activemetabolism during rapid amplification. |
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