Effects of growth irradiance levels on the ratio of reaction centers in two species of marine phytoplankton

Journal Article · Thu Oct 01 04:00:00 EDT 1981 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.68.4.969· OSTI ID:5926987

Falkowski, P G ^[1]; Owens, T G; Ley, A C; Mauzerall, D C

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1. Brookhaven National Lab.

Cells of two species of single-celled marine algae, the diatom Skeletonema costatum (Greve), Cleve, and the chlorophyte Dumaliella tertiolecta Butcher, were cultured in white light of high (500-600 microeinsteins per square meter per second) and low (30 microeinsteins per square meter per second) intensity. For both algal species, cells grown at low light levels contained more chlorophyll a and had a lower ratio of chlorophyll a to chlorophylls b or c than did cells grown at high light levels. When photosynthetic unit sizes were measured on the basis of either oxygen flash yields or P/sub 700/ photooxidation, different results were obtained with the different species. In the chlorophyte, the cellular content of photosystem I (PSI) and photosystem II (PSII) reaction centers increased in tandem as chlorophyll a content increased so that photosynthetic unit sizes changed only slightly and the ratio PSI:PSII reaction centers remained constant at about 1.1. In the diatom, as the chlorophyll content of the cells increased, the number of PSI reaction centers decreased and the number of PSII reaction centers increased so that the ratio of PSI:PSII reaction centers decreased from about unity to 0.44. In neither organism did photosynthetic capacity correlate with changes in cellular content of PSI or PSII reaction centers. The results are discussed in relationship to the physical and biological significance of the photosynthetic unit concept.

• OSTI ID: 5926987
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 68:4; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550500* -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
AQUATIC ORGANISMS
BIOLOGICAL EFFECTS
CELL CULTURES
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
COMPUTER CALCULATIONS
DATA
DOSE-RESPONSE RELATIONSHIPS
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
INFORMATION
NUMERICAL DATA
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYTOPLANKTON
PLANKTON
RADIATIONS
SPECIES DIVERSITY
SPECTROPHOTOMETRY
SYNTHESIS
THEORETICAL DATA
VISIBLE RADIATION