I want to know.......... - Page 2 - Aquarium Plants

Carissa · 05-24-2008, 01:59 PM

Image:Spectra-Philips 32T8 natural sunshine fluorescent light.png - Wikipedia, the free encyclopedia

This shows the spectrum of a "natural sunshine" fluorescent bulb, it appears that many wavelengths are represented here. For comparison you can look at the wavelength of older type fluorescent bulbs here, they were less comprehensive.

Image:Spectrum of halophosphate type fluorescent bulb (f30t12 ww rs).png - Wikipedia, the free encyclopedia

Carissa · 05-24-2008, 02:07 PM

Quote:

Originally Posted by ceg4048

Intensity seems to have as much to do with the color change but each intensity value also has spectral components so that when a plant has grown to 8 inches tall even though it is under the same bulb it's receiving more red or more blue than when it was only 4 inches tall so this could trigger the pigment redistribution.

I think that it would be extremely difficult to test sunlight vs. other forms of light, since controlling for intensity would be very difficult if not nearly impossible.

essabee · 06-08-2008, 12:51 AM

All that I could find is :-

http://www.dsls.usra.edu/meetings/bio2001/pdf/043.pdf

Tom Barr · 06-08-2008, 01:37 AM

Quote:

Originally Posted by ceg4048

I see no difference in bushiness or legginess as a result of spectral variation. This makes sense because the spectral emission of the sun is wide and changes during the day being red(ish) in the morning blueish at midday, however due to the local environment of a plant at any given location, the spectral quality that plant receives can vary wildly from that of the sun due to shade or reflection. It would therefore be self defeating for a plant to only be able to use one or two narrow bands of light.

Cheers,

And this type of insight is sorely lacking in the hobby.
Folks seem to assume that the specta never changes throughout the day(ADA sale's pitches talk a lot about nature, then do things differently ironically).

So what real use are the spectras unless you measure them in situ?
While interesting, the plants generally adapt to the patterns and the overall range of PPFD/PAR seems to be the best correlation for growth.

Our own color perception also seems to be a large factor.

When people suggest natural systems as their model, they ought to stick with it.
Adding high levels of CO2 like industrial agriculture, is hardly "natural" or "using natures subtle sublime presence".

These systems and the sales pitches are plainly put: artificial.
The filtering from forest etc, other plants etc is hard to predict where it takes place in natural systems and how it impacts evolution. Many species are from lakes and marshes with no trees near.

Regards,
Tom Barr