The Three Red Algal Photosynthesis Pigment System Is A Comparative Study

This study was divided into three parts: Comparison between leafy gamephyte and free-living conchocelis of Porphyra haitanesis Chang et Zheng in on pigment compositions and isolation of phycoerythrin (PE), phycyanin (PC), phycobilisome, thylakoid membrane and photosystem. The leafy gamephyte and free- living conchocelis of P. haitanesis showed clearly difference in content of pigment. PE was their main pigment protein, and the PE content of P. haitenesis leafy gametophyte and free- living conchocelis were 2.9 and 4.2 mg/ g fw, respectively. The phycobilisomes from leafy gametophyte and free- living conchocelis of P. haitanesis had no significantly different in absorption spectra, fluorescence emission spectra and polypeptide composition. The thylakoid membrane of P. haitanesis leafy gametophyte had two kinds, which consisted of PSⅠand PSⅡ, respectively. The extrinsic proteins of PSⅡincluded five extrinsic proteins (33, 20, Cytc 550, 15, 12 kDa proteins). In comparison, the thylakoid membranes (B2 and B3) were isolated and purified from free-living conchocelis of P. haitanesis by sucrose density gradient ultracentrifugation. B2 and B3 showed similar absorption and fluorescence emission peaks, while B3 had a relatively higher O2 evolution rates and DCIP photoreduction activities. Intact PSⅡconsisted of four extrinsic proteins previously reported in other red algal PSⅡparticles (33, 20, cytc 550 and 14 kDa proteins). 2. The wile type and gametophytic blade mutant of Porphyra yezoensis Ueda from Porphyra farms in Rudong of China were compared in their composition of pigmentation and phycobilisome. The green mutant was characterized with lower PE and higher PC content in comparison with wide-type. Moreover, the green mutant was resulted from cytoplasmic mutation by crossing the mutant with the wild- type, while this cytoplasmic mutation was absent ofγ- subunit of PE, which was encoded by nuclear. 3. In order to investigate the possible effects of the ecological environment on photosynthetic activity and the major light harvesting complex, the oxygen evolution rates and compositions of phycobilisome from freshwater red alga Compsopogon coeruleus (Balbis) Montagne that could grow and reproduce in salinities up to 35 ppt, were studied. Results showed that C. coeruleus tolerated inorganic ion at a relatively lower concentration. The PE from C. coeruleus consisted ofα,βandγsubunits, which only carried phycoerythrobilin, phycocyanobilin and absence of phycourobilin, suggesting that PE from C. coeruleus was a new type.