34 Photosynthesis

Abstract

Arabidopsis photosynthesis has not been studied in a systematic manner; rather, many investigators have applied their particular expertise to Arabidopsis because of the oft-stated advantages in genetic and molecular studies. Consequently, the information available on Arabidopsis photosynthesis is very detailed in a few areas and totally absent in many others. In this review, I have considered photosynthesis from a functional perspective, referencing those papers that provide information on the biophysics, biochemistry, and physiology of the energy transduction and CO₂ assimilation processes. This account, which cites most of the individual papers on Arabidopsis photosynthesis, can therefore serve as a starting place for individuals interested in pursuing either the molecular mechanisms or genetics of this topic.

THYLAKOID MEMBRANES
Chlorophyll
The earliest Arabidopsis mutants were identified on the basis of a visual phenotype, and plants deficient in chlorophyll b were among the first characterized (Röbbelen 1957). Similar mutants were described by Hirono and Rédei (1963) and Kranz (1973). The chlorophyll b mutants grew more slowly than wild type and had reduced levels of accessory pigments, but no measurements of any photosynthetic parameter were made. In addition to plants deficient in chlorophyll b, several mutants with temperature-sensitive alterations in chlorophyll content have been selected (Markwell and Osterman 1992). In all cases, the specific biochemical defect leading to the absence of chlorophyll b or to alterations in chlorophyll content is unknown.

More recent analyses of Arabidopsis chlorophyll b mutants found that such plants lack the photosystem II (PSII) light-harvesting chlorophyll-protein (LHCPII) complexes (Rühle et al....