Publication Abstracts

Kiang et al. 2007

Kiang, N.Y., J. Siefert, Govindjee, R.E. Blankenship, and V.S. Meadows, 2007: Spectral signatures of photosynthesis I: Review of Earth organisms. Astrobiology, 7, 222-251, doi:10.1089/ast.2006.0105.

Why do plants reflect in the green and have a "red edge" in the red, and should extrasolar photosynthesis be the same? We provide: 1) a brief review of how photosynthesis works; 2) an overview of the diversity of photosynthetic organisms, their light harvesting systems, and environmental ranges; 3) a synthesis of photosynthetic surface spectral signatures; 4) evolutionary rationales for photosynthetic surface reflectance spectra, with regard to utilization of photon energy and the planetary light environment. We found the "NIR end" of the red edge to trend from blue-shifted to reddest for, in order, snow algae, temperature algae, lichens, mosses, aquatic plants, and finally terrestrial vascular plants. The red edge is weak or sloping in lichens. Purple bacteria exhibit possibly a sloping edge in the NIR. More studies are needed on pigmentprotein complexes, membrane composition, and measurements of bacteria to draw firm conclusions about the role of the NIR reflectance. Pigment absorbance features are strongly correlated with features of atmospheric spectral transmittance: P680 in PS II with the peak surface incident photon flux density at ∼685 nm, just before an oxygen band at 687.5 nm; the NIR end of the red edge with water absorbance bands and the oxygen A-band at 761 nm; and bacteriochlorophyll reaction center wavelengths with local maxima in atmospheric and water transmittance spectra. Given the surface incident photon flux density spectrum and resonance transfer in light harvesting, we propose some rules for where photosynthetic pigments will peak in absorbance: a) the wavelength of peak incident photon flux; b) the longest available wavelength for core antenna or reaction center pigments; and c) the shortest wavelengths within an atmospheric window for accessory pigments. That plants absorb less green light may not be an inefficient legacy of evolutionary history, but may actually satisfy the above criteria.

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BibTeX Citation

  author={Kiang, N. Y. and Siefert, J. and Govindjee and Blankenship, R. E. and Meadows, V. S.},
  title={Spectral signatures of photosynthesis I: Review of Earth organisms},

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RIS Citation

ID  - ki08000d
AU  - Kiang, N. Y.
AU  - Siefert, J.
AU  - Govindjee
AU  - Blankenship, R. E.
AU  - Meadows, V. S.
PY  - 2007
TI  - Spectral signatures of photosynthesis I: Review of Earth organisms
JA  - Astrobiology
JO  - Astrobiology
VL  - 7
SP  - 222
EP  - 251
DO  - 10.1089/ast.2006.0105
ER  -

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