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Abstract Detail


Physiological Section

Thorhaug, Anitra [1], Berlyn, Graeme P. [2].

Thalassia testudinumís spectral reflectance and partial absorption responses to blue, red, and white colored light at diminishing light intensities compared with Zostern marina responses.

The spectral reflectance and partial absorption responses of the seagrass Thalassia testudinum was studied under diminution of light incubations simultaneously with the mono-colors red and blue light plus white light. The 6 month seedlings and mature plants were exposed for 6 h (morning to mid-day) to randomly varied light intensity from 75% to 10% (Ashton-Berlyn apparatus) and two colors red and blue in collodion filters. The results at low light intensities (10 and 23%) showed the blue-light incubated specimens responded with high partial absorbance and low reflectance between 400 nm and 500 nm (the range of many accessory pigments) and far less activity in chlorophyll a in the 680 nm area than did those incubated at the same low intensities in the red or white light. Also the red-light-incubated specimens did not exhibit the same accessory pigment responses as the blue-incubated specimens in the 400 to 500 nm range except at the 450 and 480 nm wavelengths. The green edge effects shifted downward both with diminished light intensity and with color change from red and white to blue. At 23% the accessory pigment showed activation of high peaks of partial absorption and troughs of reflectance apparently indicating activated carotenoids and xanthophylls for Thalassia . The Zostera effect was not as pronounced as Thalassia, especially in the lower ranges 400-550 nm and in the wavelengths where green edge decreased with blue color and diminished intensity light. No response differences between age groups of Thalassia were found.


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1 - Yale University School of Forestry & Environmental Studies, 1359 SW 22 TER, Miami, Florida, 33145, USA
2 - Yale University, School of Forestry and Environmental Studies, Greeley Memorial Laboratory, 370 Prospect Street, New Haven, CT, 06107, USA

Keywords:
Thalassia testudinum
Zostera marina†
Spectral reflectance
partial absorption
red light
blue light
carotenoids
green edge
edge effects
xanthophylls
light dimunition
white light.

Presentation Type: Oral Paper:Papers for BSA Sections
Session: 39
Location: Wasatch B/Cliff Lodge - Level C
Date: Tuesday, July 28th, 2009
Time: 10:45 AM
Number: 39006
Abstract ID:227


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