| Porphyra,a model system of marine algae,is economically important and valuable for theoretical study. Based on the dimorphic life cycle of porphyra,this study focused on the germinating process of conchospore and the differences between the filamentous sporophyte and leafy gametophyte,and contained three parts:1) Germinating process of conchospore which linked the filamentous sporophyte and the leafy gametophyte of Porphyra,and influences of light on the process were studied and discussed. Only the attached conchospores generated cell wall and developed into leafy gametophyte,which indicated that the attachment was the trigger of the cell wall formation and the further development. Either cellulase or pectolase can prohibit the attachment,however they acted in the different ways,which indicated that the pectin played a crucial role in the initial attachment as the cellulose did in the permanent attachment. High intensity(200μmol·m-2·s-1)visible light with wave-length≥580 nm facilitated the division rate of conchospores.2) Large-scale bioinformatical analyses were performed in the combination of 11000 ESTs from filamentous sporophyte of Porphyra haitanensis and all the available algal data. PCK-type C4 carbon fixation pathway was suggested in P. haitanensis sporophyte and 44 gene candidates up-regulated in Porphyra sporophyte were screened.3) The differences of Rubisco content and its carboxylase activity between sporophyte and gametophyte of Porphyra yezoensis,P. haitanensis,Laminaria japonica and Bangia fuscopurpurea were studied. It showed that Rubisco content and its initial carboxylase activity were notably higher in their gametophyte than those in their sporophyte. That was to say,Rubisco content and its initial carboxylase activity were not relevant to the complexity but likely to the ploidy of the generation in the macroalgae. It was speculated that Rubisco played crucial roles during the transition of generations of macroalgae.
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