Photosynthesis - Light, Absorption & Action Spectrum - YouTube

PHOTOSYNTHESIS ACTION SPECTRA IN ANACYSTIS …

Spectral dependence of photosynthesis and light absorptance in ..

Plants and other photosynthetic organisms use special molecules for absorbing light. These pigments have a distinctive color, or spectrum, that is known to leave an imprint on the light reflected off our planet's surface. A new database catalogues the diverse palette of light-absorbing biological molecules on Earth in order to better predict what the photosynthetic signature might look like on other planets.

T1 - PHOTOSYNTHESIS ACTION SPECTRA IN ANACYSTIS NIDULANS AS DETERMINED BY PHOTOACOUSTIC SPECTROSCOPY.

on the spectral dependence of photosynthesis and most ..

But plants aren't the only organisms that use sunlight on Earth. Kiang studies various photosynthetic bacteria that have an entirely different set of pigments for absorbing light. She compares the spectra from these pigments to try to understand what mechanisms drive the evolution of the light harvesting ability.

Photosynthesis and electromagnetic spectrum

As a reminder, photosynthetically active radiation (PAR) does not consider the spectral response of plants (FIG. 3); it simply represents the number of photons (quanta) per unit area per second within the range of 400 to 700 nm. With the availability of color-tunable LED modules for greenhouse lighting, horticulturalists will likely want to experiment with different SPDs for specific crops and flowering plants, as well as both the directionality and daily timing (photoperiods) of the luminaires. Regardless, being able to convert predicted and measured illuminance values to PPFD values for common light sources will certainly ease the communication problem between lighting designers and horticulturalists.

mr i explains: Action and Absorption Spectra of Photosynthesis - YouTube


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But Lindsey says we have to be careful about this type of speculation. Porphyrins and other details about Earth's photosynthetic chemistry may merely be "a consequence of numerous contingencies and frozen accidents — i.e., workable but perhaps non-ideal solutions that became locked-in early on and have never changed in the course of evolution."

LED Light Spectrum 101: Absorption spectra | …

As noted by McCree (1972a), neither PPFD (quantum flux density) nor YPFD (irradiance) are perfect measures of photosynthetically active radiation in that both systematically overestimate the effectiveness of blue light relative to red. As can be seen from FIG. 3, the error is greater for YPFD, which explains why PPFD measurements are preferred by horticulturalists. Nevertheless, they are useful in that they are independent of any particular plant species, and they can be measured both in the laboratory and in the field using a radiometer with a spectrally-calibrated quantum sensor such as the LI-190SA with LI-COR ().

LED Light Spectrum 101: Absorption spectra

Green light is also used in photosynthesis, as can be seen from the leaf action spectrum (FIG. 2). It has been established that green light drives photosynthesis more effectively than red or blue light deep within the leaf (Terashima et al. 2009). Further, the insects used in greenhouses as pollinators and biological control agents see best in the green and ultraviolet regions of the spectrum. More interestingly, changes of even 10 nm in the peak wavelength of green light can have dramatic effects on the growth of plants such as lettuce (Johkan et al. 2012).

Triplet excited state spectra and dynamics ..

In addition to using chlorophylls and carotenoids for photosynthesis, plants use these and other photopigments for a wide variety of functions. The phytochromes Pr and Pfr, for example, respond to 660 nm red and 735 nm infrared radiation respectively, and in doing so induce seed germination and flowering, regulate leaf expansion and stem elongation, and trigger photoperiod and shade avoidance responses (see Appendix A).

13/01/2011 · SpringerLink

Plants and other photosynthetic organisms use special molecules for absorbing light. These pigments have a distinctive color, or spectrum, that is known to leave an imprint on the light reflected off our planet's surface. A new database catalogues the diverse palette of light-absorbing biological molecules on Earth in order to better predict what the photosynthetic signature might look like on other planets.