Photosynthesis Under Solid State Light. Setting the Standards .

Cannabis Sativa L ,needs light ..
A lot of quanta...

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And now the real "unknown world " ,regarding
Cannabis Sativa L .

The species' Circadian Rythms ....

Daily Light Integral and Pfr / Po....
Cannabis Sativa L . is way sensitive plant species ,
regarding duration of light and Far Red light Exposure ....

"Playing" with light regime and Far -red illumination ,
affects many aspects .
Really strongly.
In many of ways ,also.


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===============================================================


====================================================================

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As for the CS-RQE action Spectra ....
Read on ...

----
DETECTION OF CANNABIS PLANTS
BY HYPER-SPECTRAL REMOTE SENSING MEANS

ABSTRACT:
The dramatic increase of drug use, mostly hashish and marijuana, reinforces the demand for drug prevention and the need for accurate and updated information on cannabis fields. This study sought to evaluate the ability of Hyperspectral spectroscopy to discriminate cannabis from different scales and land use. The study was conducted in three stages: 1) Examination of the cannabis spectrum under laboratory controlled conditions from a short distance with field spectrometer and Hyperspectral camera under artificial light; 2) Remote sensing of the cannabis from an oblique view using static imaging spectrometer from 25m and 80m; and 3) Airborne Hyperspectral pushbroom sensor (AISA Eagle 400-1000 nm). This method of down/up scaling was found to be useful in understanding the meaning of spectral discrimination. Results of Principal Component Analysis (PCA) show that the spectral signal of cannabis (leaf and canopy) varied with distance from the sensor, however spectral bands with the most influence are in the range of 530-550, 670-680 nm and 705-720nm.

===============================================================
Development of Cannabis Spectral Signatures
And Cannabis Growth Simulation Model



=======================================================================
Spectral Discrimination of Cannabis sativa L.

...(...)...Leaves and Canopies
were in the 550 nm and 720 nm wavelength regions.
Spectral differences between marijuana and tree species
were larger than the differences between marijuana and
other herbaceous species. Again, the greatest differences
were near 550 nm and 720 nm. The “red edge” region
near 720 nm warrants further investigation. It may be
possible to exploit reflectances differences in the slope
of the red to near-infrared transition for species discrimination.
Canopy reflectance spectra of marijuana and several
representative species were simulated for a wide range
of LAI and background reflectances. Major differences
in canopy reflectance of marijuana and other plants were
observed near 550 nm, 720 nm, and 800 nm. Dense canopies
of marijuana were more spectrally discriminable
from other vegetation than sparse canopies. Thus, based
on measured leaf spectra and simulated canopy reflectance
spectra, we would choose several relatively narrow
(i.e., 30 nm or less) spectral bands in the green (550
nm), red (670 nm), “red edge” (720 nm), and the near-infrared (800 nm)
to discriminate marijuana leaves and
. canopies from other species.
=============================================================

.....




CS-RQE Cannabis Sativa dedicated action spectrum ,
points out easily, all of the above mentioned , pretty clear ....
Don't you think so ?

-Green ~547 nm ' droop '
-Red 674 nm "max rel. peak ' (!!! )
-Higher numbers of quanta absorbed & utilised ,
than those the other standards,
suggest ,between 700-720nm(FR )

Pretty easy ,to notice all those ...



"Herb's" wl specific ' biases' and 'preferences' ......

Case closed ?



Cheers.

One of the reasons I didn't do a 13hr on yet. More electricity for how much gain in yield?

Increased potency of plants in brighter conditions.

Good to know I'm on the right track when I read through these things...I got stuck on those two articles earlier.

I actually picked up a co2 exhale bag recently. Used them before with nice results I thought. After reading this..temp of 30c..small boost in co2..high light irradiance..can't wait to see the results. My minimal airflow should keep the co2 in the room and I've heard gorilla tents do a decent job of containing it.

Two more action Spectrums ....

Tazawa (1999)


Inada (1976-7 )

Far as I can tell that looks pretty darn well and done. A few trials of lessening nm in certain areas would hit a more ideal "specialized" flowering spectrum possibly..would love to see a grow with that spectrum..closest I can think of to that would be a cmh.

What's the spectrum chart of the spectral dot versus the new action spectrum I wonder..or even the 3000k 3070

Surprisingly, the amount of CO2 in human exhale is not to be underestimated. Normal exhale is 40000 PPM and if you hold your breath it can be as high as 80000 PPM. When the humid season comes to my area I shut the windows and run the AC and dehumidifier to keep humidity under control. If you have a good sized garden the CO2 levels can drop very low in those conditions so it makes a lot of sense to exchange the air in your living space with the air in your indoor garden. I have been very curious about the difference between the two air masses so CO2 meter is on its way for some testing

Positivity said:

Far as I can tell that looks pretty darn well and done. A few trials of lessening nm in certain areas would hit a more ideal "specialized" flowering spectrum possibly..would love to see a grow with that spectrum..closest I can think of to that would be a cmh.

What's the spectrum chart of the spectral dot versus the new action spectrum I wonder..or even the 3000k 3070

Click to expand...

One thing at a time ....
Step by step ...


Cheers.

1. Quantum Flux Analysis of Hypothetical Light Source ,
with an emission spectra ,according to CS-RQE -2014 action spectrum.

SSL light source with photon fluence rate of 1000 μmol m-2.s-1
-----------------------------------------------------------------------------------------
Quanta distribution absolute function.



Notes:

1)
Cannabis Sativa L. utilises plenty of blue photons at high irradiances.
( PAR 400-700 photon fluence rate of source = 930.9 μmol m-2.s-1 )
268.41/930.9*100=28.86 % of the quantum flux (mostly in Cyan )
And Guod was right all along ,about his choices ,regarding the blue leds and the Cool white ones.
As also for the deep reds.

Monos are back,ladies and gentlemen !
( Cyan !!! & deep-deep red ones !!! )


2) Most interesting is the multiplier factor resulting ,
used to convert quantum flux / fluence to Radiant Watt / irradiance and vice versa ..
4,65 umols /sec per Radiant Watt ....
Interesting ,enough ....




......................................................................................................................................................................................

Food for thought ...


Cheers .

2. Radiant Analysis of Hypothetical Light Source ,
with an emission spectra ,according to CS-RQE -2014 action spectrum.

SSL light source with photon fluence rate of 1000 μmol m-2.s-1.
Radiant power resulting at range 400-780 nm,from thr CS-RQE SSL spectrum is 214,85 radiant Watts .

(1000 umol/sec / 214,85 W = 4,6544 umols/sec/W )
-----------------------------------------------------------------------------------------
Absolute Radiant Power distribution function.

PAR 400-700 nm Radiant Φ = 203.33 W .....
35,14 % of power is in 'blue' 400-499 nm range .Mostly in Cyan .
( refer to CS-RQE_2014.text )



Notes


1) Sunlight max ....1120 W/m2
~43% falls within 400-700 nm PAR range ....
0.43 * 1120 = 481.6 Watts /m2 ...Max.
......
......


481.6 * 4.6 =2215.36 μmol/sec/ m2

http://en.wikipedia.org/wiki/Sunlight
http://en.wikipedia.org/wiki/Solar_irradiance
http://en.wikipedia.org/wiki/Solar_constant


Cheers.

Some of the deep red choices. Looks like a luxeon ex7 would be a nice bin to try. I'll stick with the oslon for now..it does have a bit wider nm range I think

Cyan is interesting. The blue attributes must be strong though?

Few charts then break time..lol

Positivity said:

Does appropriate photosynthesis spectrum include benefits of uv and ir levels?

I would assume ir since it's so important for normal flowering

This will be an interesting topic

Click to expand...

Positivity said:

Far as I can tell that looks pretty darn well and done. A few trials of lessening nm in certain areas would hit a more ideal "specialized" flowering spectrum possibly..would love to see a grow with that spectrum..closest I can think of to that would be a cmh.

What's the spectrum chart of the spectral dot versus the new action spectrum I wonder..or even the 3000k 3070

Click to expand...

Positivity said:

Is that spectrum appropriate for our plant species ?
From which latitude is that spectrum taken ?
Why?
For which type of plants that Standard is intended ?
For which types of cultivation ?
Where and when ?
Spectrum looks good except for flowering. fire: R u Sure about that ? ) So something like that you could possibly lead to fastest growing plants possible. Veg. Although the level of red may give more stretch in veg than desired..maybe not. The amount of blue would leave airier flowers I'd assume. So a modification of the perfect spectrum would be needed to suit morphological preferences of a particular plant

Din5031-.10....isn't it just a global action spectrum for a averaged vegetation type?

Bout' all I can muster..will read a bit more

Click to expand...

IR .......

Fr ....
Pfr/Pr and flowering ......




Check this :



At Transmittance curve .....At 22 September ,closing to the end of annual cycle ,cannabis plants ,
Transmit way less FR than in 5 of June ..Ok ?

Most probably due to leaves thickening and/or waxy photoprotective depositions ,on leaf surface,
after a long hot 'n shinny summer ,one should normally suspect ....

Ok ...Energy can't just get "lost " or"vanished " .....

Then that light should be reflected back !
Ain't so ?
..............

On the Reflectance curve ,at 22 September not only there's not an increaseof FR reflectance as expected ,
but actually is reflected back less of FR ...

Oh-ohhhh...
Huston,we have plenty of FR quanta missing in action..
Are they really ,missing in action ?


Who said that Cannabis needs red light for flowering ?

At 22 of September,actually plenty of red is reflected back

( Plants while maturing ,PS rates drop..
Ain't normal for plants to absorb and utilise red quanta as when in younger age ...
And guess what more ..
They ca not ' stretch ' anymore,either ....
Plants will soon be dying ...
But...
Then...
For which red light we're/ have been talking about ,actually ? )

FR !!!!!

Can you believe it ?

Stupid fuckin' HPS ....
For all what's worth ,best flowering lamps ,at plant's late age of plant would be Halogen or
even the almost extincted unefficient incandenscents !

Or ..maybe .the much more efficient 2700K ,high CRI Warm Whites ,present...
Or even better maybe ,,,,
The QD ones ..."The Halogen spectrum cobs' of Mole -Richardson,for example
..
With plenty of Neutral or cool white leds ..And cyan ones ...
Only blue/ cyan and Far red ,wls are used mainly in ( late ) flowering ,from Cannabis plants ...

.....

Nope..
None of these can be right ....
None ...

I can't really trust that CS-RQE is real ....
Although science,research and some 'weird coincidences' of numbers ,say otherwise ....

No..
Somewhere I've done a huge mistake ....

Click to expand...

...

Cheers.

-

Cyan wls ,stomatal aperture ,high irradiances and CO2 uptake ....

...............................
Just to make things ,even worse ....

And another great aspect of white phosphor conversion led/cobs is emerging ...

Spectral shift with dimming ...

Lots of current ? Lots of blue photons ...
Less current ...More red and FR photons ....

Dim your whites as flowering progresses ...



Less irradiance wiil do fine ,along with a bit more FR ....

I have long been a fan of 2-3 separate o/o switches

Why not minimize white by adding reds and blues once buds set?

I use the 2 @ 90w ufos that Jeff gifted (3500/5000) with no lenses.

I got the 2@ 3ft BML bars with a mix of 2700/3000 + ~ 5% @ 450 & 660 to add once buds set.

As these bars are currently in the SPYDR tent, I introduced a commercial 1 x 4 troffer panel @ ~ 40w WW, which in effect reduces the percentage of ~ 4500

As to light in June v September, even on the equator, the RH and temps change enough to trigger flowering

There is much natural interplay we do not know

There will always be a finer point

Pragmatism wins the day

Photosynthetic Quantum Yield Dynamics: From
Photosystems to Leaves

(...)
Despite blue light being widely used to excite PSII, it is the
longer blue wavelengths (460 to 500 nm) that strongly overexcite
PSII and not the blue wavelengths around 445 nm used here
(Evans and Anderson, 1987; Figures 6A and 7A). However, pure
blue light around 445 nm is expected to excite cryptochromes
more strongly than the sunlight- and shade light spectrum in our
treatments (Ahmad et al., 2002) and produces a phytochrome
signaling that is closer to that of the shade light spectrum
treatment than of the sunlight spectrum treatment (Sager et al.,
1988; Hogewoning et al., 2010c). So far little is known on the
role that nonphotosynthetic photoreceptor signaling plays in
photosynthetic acclimation (Dietzel et al., 2008. ) (...)

(...)
The absolute maximum quantum yield for CO2 fixation or O2
evolution has been a subject of debate for a long time (Govindjee,
1999). We found a maximum quantum yield of 0.093 CO2 fixed
per absorbed photon for the sunlight spectrum– and blue light
grown–leaves at 620 to 640 nm (Figure 2B; see Supplemental
Table 2 online). Correction for quantum yield losses due to imbalances
in photosystem excitation at these red wavelengths
increased the maximum value of a to 0.0955 for all three growth
light treatments. Since McCree (1972a) concluded that enhancement
effects are insignificantly small for white light, not
much attention has been given to the issue of enhancement
effects (i.e., the quantum yield of a combination of wavelengths
is higher than the sum of the parts) (Emerson et al., 1957).
However, we show that most wavelengths in the range 400 to
670 nm overexcited PSII slightly or more strongly, dependent on
the growth light treatment, while wavelengths in the range 685 to
730 nm strongly overexcited PSI (Figures 6A and 7A), as suggested
in the work of Evans and Anderson (1987). Also, leaves
tune their photosystem stoichiometry to the spectrum of their
growth environment, resulting in increased light use efficiency
see section above; Chow et al., 1990). So, while the longer
wavelengths (>700 nm) individually produce relatively low values
of a (Figure 2B) due to PSI overexcitation (Figures 6A and 7A),
there is no reason to assume that a would be suboptimal for
these long wavelengths in the presence of other wavelengths
that balance the photosystem excitation. Therefore, the contribution
of the longer wavelengths (700 to 730 nm) to the quantum
yield is expected to be significant when measuring the maximum
a with a broadband light source extending to the near infrared
(NIR). Our calculation showing a significant enhancement effect
on the value of a for both the shade light and sunlight spectrum,
and the larger enhancement for the shade light spectrum (Table 3),
confirms this expectation.
Enhancement effects have consequences for quantum yield
measurements. In some studies on the maximum quantum yield,
a quantum sensor (sensitivity 400 to 700 nm) was used to
measure the quantum flux of broadband actinic light containing
wavelengths >700 nm (Björkman and Demmig, 1987; Long
et al., 1993). When the wavelength range 700 to 730 nm is not
taken into account, quantum yields are overestimated because
the absorbed photon flux is underestimated, and, perhaps more
importantly, this wavelength range is the most important for
enhancement effects.
(...)

http://www.plantcell.org/content/24/5/1921.full

PetFlora said:

Does this suggest the ~ 730 should be available throughout.... and if yes, how much (?%).... or is using it at ~ 5-10 minutes after lights out sufficient?

Click to expand...

(...)
CONCLUSIONS
Adaxial surface reflectance of marijuana leaves exhibited
the typical healthy green leaf spectral signature of low
visible reflectance and high near-infrared reflectance. No
unusual or distinctive spectral features were evident
when the data were presented as reflectance. Leaf transmittance
also showed no surprises. Seasonal changes in
leaf reflectance showed a progressive increase in visible
reflectance of the 400–700 nm wavelength region. From
700–1000 nm the trends were less clear. Transmittance
differences over the visible region changed from a generally
positive difference to a negative difference as the
season progressed. Near-infrared transmittance showed an
increasing negative difference over time. The magnitude
of the differences were greater for transmittance
than for reflectance. N-fertilization effects were evident in
spectra of the marijuana leaves. The magnitude of the
spectral differences between N-treatments varied over
time with most differences occurring in the visible wave
length region. Lower N-treatments tended to have a
higher visible reflectance.

Spectral Discrimination of Cannabis sativa L.
Leaves and Canopies

And the much favored 660 nm red for flowering purposes ....





From :

FOLIAR PIGMENTS AND THEYR DYNAMICS DURING DIFFERENT
VEGETATION PHENOPHASES IN FIVE CULTIVARS OF CANNABIS SATIVA L.

And just to get an general idea of the accuracy of digitized graphs ...

An example ..
(In fact I'm doing it right now ...)

Manually digitizing a Cree's 2700K 80 CRI standard* phosphor's conversion spectral plot.
Nano per nano !!


(*Same phosphor blend of all 2700K 80 CRI leds of the brand/manufacturer.
Mostly serving for consistent CCT binning purposes .
Thus ,phosphor blends are kept same ,no matter the type of led/cob ,as 'standard' 'recipies-blends' )