Thorhaug, Anitra , Berlyn, Graeme , Poulos, Helen .
The spectral reflectance indices compared for blue, green, orange, red, and white light diminution on Atlantic temperate Zostera marina, a seagrass.
Spectral reflectance's analytical power has two fundamental bases: 1. ) Einstein's discovery "light consists of particles", called photons. 2.)Feynman's discovery (1985) "light is not really affected by surfaces". As a photon becomes incident on a plant's leaf surface, this photon interacts with electrons throughout the leaf. The photon is then scattered while a new photon is emitted (electrons can absorb one photon and emit another photon). Consequently, the "reflected" light characterizes the signature of the light-absorbing elements of the leaf, the pigments. If light solely struck the leaf surface and bounced off, it would not show this characteristic reflectance spectra. Reflectance spectra have a fundamental identity in a species, but the quality and quantity of the reflectance of a species depends on the physiological state. Indices of spectral reflectance allow scale-able statistical delineation among physiological responses. Measurements are amenable to remote sensing of community health. We have previously used them over a variety of types of plants (from vascular alpine to desert and marine phyla). The seagrass, Zostera marina indices will be examined in detail for experiments using red,orange, green, and blue diminishing light intensities. We compare normal indices including PRI (photosynthetic efficiency), VAZ (viola, anthero, and zeaxanthins), red and green edges, Chl NDI and Chl NDVI ( chlorophyll normalized Vegetation Index), plus new indices created for the carotenoid and xanthophyll intensities and Gitelson's older carotenoid indices viewed in contrast to both in spectral reflectance and partial absorption curves. The comparison of white light indices to the colored light indices and intensities for SIPI, chl green edge, chl red edge, DD, and our new indices focused on Xanthophylls' responses will be delineated. Clearly seen are higher photosynthetic efficiencies at 23% light dimunition under all four colors with intense activation of specific pigments below 505nm and less activation of Chlorophyll. Blue light responses differed from red light responses.
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1 - Yale University, School of Forestry and Environmental Studies, 370 Prospect St, New Haven, ct, 06511, usa
2 - Yale University, School Of Foresty & Evironmental Studies, GREELEY LAB-370 PROSPECT ST, NEW HAVEN, CT, 06511, USA
3 - Wesleyan University, Environment Department, Science Tower 74, Middleton, CT, 06511
photosynthetic efficiency (PRI)
CHL NDVI ( Chlorophyll normalized Vegetation INdex
species reflectance signature.
Presentation Type: Oral Paper:Papers for Sections
Location: Union C/Hyatt
Date: Wednesday, July 11th, 2012
Time: 11:00 AM