Effects of growth irradiance levels on the ratio of reaction centers in two species of marine phytoplankton [Skeletonema costatum, Dunaliella tertiolecta, Algae]

Cells of two species of single-celled marine algae, the diatom Skeletonema costatum (Greve), Cleve, and the chlorophyte Dunaliella 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) in...

Full description

Saved in:
Bibliographic Details
Published in:Plant physiology (Bethesda) 1981-10, Vol.68 (4), p.969-973
Main Authors: Falkowski, P.G, Owens, T.G, Ley, A.C, Mauzerall, D.C
Format: Article
Language:English
Subjects:
Absorption spectra
Algae
Chlorophylls
Chloroplasts
Diatoms
Dunaliella tertiolecta
L cells
Marine
Molecules
Photosynthesis
Pigments
Plants
Skeletonema costatum
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Cells of two species of single-celled marine algae, the diatom Skeletonema costatum (Greve), Cleve, and the chlorophyte Dunaliella 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 $\text{P}_{700}$ 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.
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.68.4.969