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LIGHT ACCLIMATION IN PORPHYRIDIUM PURPUREUM (RHODOPHYTA): GROWTH, PHOTOSYNTHESIS, AND PHYCOBILISOMES 1
Author(s) -
Levy Israel,
Gantt Elisabeth
Publication year - 1988
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1988.tb04247.x
Subject(s) - phycobilisome , phycobiliprotein , biology , photosynthesis , botany , photosystem , p700 , acclimatization , photosystem i , photosystem ii , chlorophyll a , biophysics , cyanobacteria , genetics , bacteria
Acclimation to three photon flux densities (10, 35, 180 μE.m −2 .s −1 ) was determined in laboratory cultures of Porphyridium purpureum Bory, Drew and Ross. Cultures grown at low, medium, and high PPFDs had compensation points of <3, 6, and 20 μE‐m −2 .s −1 , respectively, and saturating irradiances in the initial log phase of 90, 115, 175 μE.m −2 .s −1 and up to 240 μE.m −2 .s −1 in late log phase. High light cells had the smallest photosynthetic unit size (phycobiliproteins plus chlorophyll), the highest photosynthetic capacity, and the highest growth rates. Photosystem I reaction centers (P700) per cell remained proportional to chlorophyll at ca. 110 chl / P700. However, phycobiliprotein content decreased as did the phycobilisome number (ca. 50%) in high light cells, where as the phycobilisome size remained the same as in medium and low light cells. We concluded that acclimation of this red alga to varied PPFDs was manifested by the plasticity of the photosystem II antennae with little, if any, effect noted on photosystem I.