caa a22 4500 445889845 CHVBK 20180317145612.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s11120-010-9612-2 doi (NATIONALLICENCE)springer-10.1007/s11120-010-9612-2 Photosynthetic carbon acquisition in Sargassum henslowianum (Fucales, Phaeophyta), with special reference to the comparison between the vegetative and reproductive tissues [Elektronische Daten] [Dinghui Zou, Kunshan Gao, Weizhou Chen] The photosynthetic oxygen evolution characteristics were examined in both vegetative (blade) and sexual reproductive (receptacle) tissues of Sargassum henslowianum (Fucales, Phaeophyta) from the Shenao bay of Nanao Island, China, to establish the mechanism of photosynthetic acquisition of inorganic carbon (Ci) in this species. In natural seawater (pH 8.1, ca. 2.2mMCi), irradiance-saturated net photosynthetic rate (NPR) was greater by 25.3% in blade than receptacle, whereas dark respiratory rate (DR) was 2-fold higher in receptacle than blade. NPR at pH 8.1 was nearly saturated with the 2.2mMCi for both blade and receptacle. However, the values of the half-saturation constant for Ci were sharply increased at pH 9.0. NPR was significantly affected, but DR was remained unchanged, with the variation of the pH values in seawater. The data from the final pH value derived from the pH-drift experiments and the comparison between the measured and theoretically estimated photosynthetic rates suggested that both blade and receptacle were capable of acquiring HCO3 − in seawater. The inhibitors experiments showed that a HCO3 − dehydration mechanism mediated by external carbonic anhydrase activity occurred in both the blade and receptacle tissues of S. henslowianum. The proton buffer TRIS had no inhibitory effect on NPR at normal pH value in natural seawater (pH 8.1), but it significantly depressed NPR at pH 9.0. This suggested that proton transport occurred at the outside of the plasma membrane facilitated the operation of the carbon acquisition at pH 9.0. It was proposed that the strategy of photosynthetic carbon acquisition at higher pH would prevent the alga from the damage of over-excitation and photoinhibition in case of sunshine and calm water. We concluded that the blade and receptacle tissues of S. henslowianum have similar mechanism of acquisition of exogenous Ci from seawater to drive photosynthesis; yet they are differentiated more or less with the photosynthetic properties. Springer Science+Business Media B.V., 2011 Sargassum henslowianum nationallicence Brown algae nationallicence Inorganic carbon acquisition nationallicence Photosynthesis nationallicence Receptacle nationallicence Marine macroalgae nationallicence Ci : Inorganic carbon nationallicence NPR : Net photosynthetic rate nationallicence DR : Dark respiration nationallicence CA : Carbonic anhydrase nationallicence AZ : Acetazolamide nationallicence DIDS : 4,4′-Diisothiocyano-stilbene-2,2′-disulfonate nationallicence TRIS : Tris(hydroxymethyl)aminomethane nationallicence APC : Apparent photosynthetic conductance nationallicence Zou Dinghui College of Environmental Science and Engineering, The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, 510006, Guangzhou, China aut Gao Kunshan State Key Laboratory of Marine Environmental Science, Xiamen University, 361005, Xiamen, Fujian, China aut Chen Weizhou Marine Biology Institute, Science Center, Shantou University, 515063, Shantou, Guangdong, China aut Photosynthesis Research Springer Netherlands 107/2(2011-02-01), 159-168 0166-8595 107:2<159 2011 107 11120 https://doi.org/10.1007/s11120-010-9612-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-010-9612-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zou Dinghui College of Environmental Science and Engineering, The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, 510006, Guangzhou, China aut NATIONALLICENCE 700 1- Gao Kunshan State Key Laboratory of Marine Environmental Science, Xiamen University, 361005, Xiamen, Fujian, China aut NATIONALLICENCE 700 1- Chen Weizhou Marine Biology Institute, Science Center, Shantou University, 515063, Shantou, Guangdong, China aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 107/2(2011-02-01), 159-168 0166-8595 107:2<159 2011 107 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer