LM301H vs LM301H-EVO
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Prawn Connery
Well-Known Member
Oh, I have a minor issue with THC level comparison between then and now, and that's because a lot of the testing done 40-50 years ago used seeded samples with a lot of stalk and leaf and dubious curing methods . . . Have a look at what @sfw1960 posted – that's wat they were testing. I also remember when I scored weed as a kid I had to ask "Is it head (flowers) or leaf?" No-one would even think to smoke leaf these days! (Still gets you high.)
Charles U Farley
Well-Known Member
I would absolutely love to see what journal those studies came from, as that is an incorrect statement.
That is one of the greatest obstacles for doing double blind LSD research, or any psychedelic research for that matter. Every participant knows exactly who got the real thing and who got the placebo, so it's impossible to obtain objective information on the effects of psychedelics from the participants.
Yea, maybe look at the data before you try to be scientific and mask hypothesis as theories.
Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects - Neuropsychopharmacology
Growing interest has been seen in using lysergic acid diethylamide (LSD) in psychiatric research and therapy. However, no modern studies have evaluated subjective and autonomic effects of different and pharmaceutically well-defined doses of LSD. We used a double-blind, randomized...
doi.org
30 % of placebo doses were misidentified as LSD (even high dose). Furthermore the doses themself are not correctly idefied in many cases which points at the dose effect relationship not being as strong as people hope it to be. You can find many more studies if you are interested. The old studies should be especially interesting in that regard.
Prawn Connery
Well-Known Member
Anyway, I'm guessing we have all smoked a lot of pot in our lives and are all in a good position to judge how high we've been. This is not the same as asking someone who has never smoked pot to rate their high.
We are also getting a bit off track (or maybe not), so maybe we should be having that argument about whether higher-energy photons (blue/violet/UVA) stimulate secondary metabolite production, including cannabinoids.
We are also getting a bit off track (or maybe not), so maybe we should be having that argument about whether higher-energy photons (blue/violet/UVA) stimulate secondary metabolite production, including cannabinoids.
Sure you can. I thought for months after my first trip that I had a dud and nothing happened, despite ...you know... the windows turning pink and wobbly. I even have a written note being convinced of it 6 weeks after.
My point is that even a simple binary question (have you taken LSD) can't be answered reliably. And then to go the stretch and say that a different drug effect 30 years later is because the drug changed and not because the subject changed is difficult in my mind.
We can now discuss the data extensively (eg is looking at the mean useful when discussing subset analysis), look at other studies etc. but that's beside my point.
Prawn Connery
Well-Known Member
Your point is valid. Up to a point. But I've already pointed that out
I'm a little confused when you say "the windows turned pink and wobbly" – an observation that appears fully cognisant – yet try to quantify this by saying you weren't sure "anything happened". I mean, you just told us something happened.
I'm just trying to be objective here. You took LSD and it had an effect – which you have noted – even though you didn't believe you took LSD at the time. (I'm assuming you now know you took LSD because you have just told us.)
That is exactly my point about the study you posted.
But I also take your point that experiences are subjective.
I was a little confused too. I understand the notion but trying to be objective is not particularly useful in this case
Charles U Farley
Well-Known Member
Anyone who has taken anything more than a _micro_ dose of real LSD knows there is absolutely no mistaking it's effects.
Kassiopeija
Well-Known Member
Yes, and with green light. Green photons are absorbed by interacting chl-b molecules which are only present in PSII. You may know the sub-canopy spec largely devoid of blue and red. Here, GL drives PSII and FRL PSI, since FRL is more prelavent the PSII enlarges to increase its light-harvesting capacity to arrive at a balanced photosystem stoichiometry.
No, you are not familiar with the EEE because you just confirmed a multitude of errors.
Also the last review you posted doesn't support your theories at all (I just read it). Most of these studies with WL vs other SPDs was with monochromatic specs. That doesn't work. Plants possess photoreceptors that respond to UV-FR/IR (280-780nm) and not many plant species grow correctly if too many regions are fully neglected. That review confirms it, but doesn't go at length to study established growlight specs and their variants like -G, +R, +B, or +R&DR to 6500-3000K base whitelight.
The EEE is an experimental artifact that shows what happens when an overexcited PSII is put into a balanced stoichiometry by the addition of FRL. The overexcitation causes a local electron-buildup at the binding site of these 2 systems. Plants can deal with this also in another way - antenna travel, then PSII delivers a bit of its energy to PSI. That's why in practical terms you cannot see this enormous enhancement in proportional biomass gains. At the end of the day a photon is a photon and regardless of color/frequency each does the same workload given it's on the PAR/ePAR range (it's not THAT simple actually, there are many fine details but is still true under this argument and alot of experiments putting PPFD to biomass in approx linear correlation confirm this).
The FRL photoprotective effect is due to the inclusion of phononic energy as necessary addition of photons >700nm in order to drive p700, the reaction center of PSI. All other wavelengths rather leave a surplus energy that needs to be quenched. The special red forms exist in a ring around the PSI core and so, can quench latent heat from there (it's the most crucial part, if the RC gets damaged the whole antenna complex cannot trap energy anymore). So this is important esp. when plants don't build up much photoprotective screening pigments like they can reactively do in the UV/B/G bands.
I'd love to see Teknik develop some nice 690-710nm diodes, they may be able to drive PSI without excessive stretching, plus have a higher absorbance. I'd put my money on it.
First, to base all your assumptions onto the chlorophyll-absorption peaks when dissolved in diethylether isolated in a flask is wrong. Yes this can tell us something about the strength of absorption BUT IN VIVO alters this, due to the spatial arrangement and various proximity of these porphyrinrings, sometimes enabling a shared orbital of the Pi-electrons and altered excitation states. So we have dimeric, trimeric or quattrimeric chlorophylls (plus some accsessory pigments) completing the absorption over a much broader range, and esp. when sampled over a much higher case incident (due to the Detour-effect) to almost homogenous uniformity within PAR, as evidenced by the McCree curve. In other words photoautotrophs just use mainly the rather narrow chlorophyll chromophore as a base building block to harvest quite dynamically and plastically over a huge bandwidth. That is why the photosystems have each +100 such molecules arranged like a funnel with the charge separating trap in its mid (or end).
The cited Bugbee control specs were often in use in either science, or, e.g. cloning. The RB actually has a super ontight SPD directly set to these native chlorophyll max peaks (high absorbance). It's rather that Bugbee's FR SPDs don't target these, so your argument is contradictory to your own "theory". In reality the FR photosynthetic effect has its max at ~730nm.
There may be a large fraction of this carbon gain due to the photomorphogenic effects of phytochrome increasing lighted out leaf surfaces / interception / photochemistry / penetration as it is impossible to disentangle all these effects in a life grow scenario. But that doesn't matter. His methods were quite rigorously and the net carbon gain has been documented. Multiple times.
Photosynthesis happens on many layers - chlorophylls / photosystems / chloroplast / leaf / plant, and science presents oftentimes only 1 snapshot out of these intertwined "dimensions".
But photomorphogenesis, to steer a plant's structure by light recipe, can critically supercede this all in importance. A bit of better photosynthesis doesn't help much when a stretchy sativa grows way too high or a stocky indica doesn't expand and needs an eternity to fill the footprint.
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cdgmoney250
Well-Known Member
I’m not sure I’ve put forward any theories other than questioning the total yield/cannabinoid efficacy of supplemental FR light in the presence of a “broader” spectrum of white light.
What I should have said, is “I’m fairly familiar with the general concept of the Emerson Enhancement Effect”…
ie- The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to light of wavelength 680 nm (deep red spectrum) and more than 680 nm (far red spectrum). When simultaneously exposed to light of both wavelengths, the rate of photosynthesis is far higher than the sum of the red light and far red light photosynthesis rates.
And my statement you quoted was indeed in error. I conflated the general mechanism of the EEE and FR role in photoprotection, assuming they only happened in tandem. Upon further reading, it does appear that FR light can ehnhance photosynthesis in certain species below the saturation of the photosynthetic apparatus (low ppfds), like @Rocket Soul mentioned previously. But it also appears that at higher light saturations (up to a limit) Far-Red light can actively reduce non-photochemical quenching by keeping Photosystem 1 in an exited state, helping keep PS I & II in a balanced state of electron donation, like you had mentioned regarding FR light and photoprotection. I confused the 2 mechanisms, sorry.
I’m not sure where you’re getting this? I’ve looked at a multitude of absorption and action spectrums of Chlorophylls/accessory pigments (with different methods of measuring) and compare them to known photosynthetic quantum yield charts, to try to gain a comprehensive understanding of how spectrum effects plants. This is such a dynamic process, that the only assumption I typically make is that sunlight is a known benchmark for plant performance, and to make my comparisons accordingly.
Again, I don’t know what theory I’ve put forward other than questioning the efficacy of added FR to a better balanced broad spectrum white light. My point in mentioning the spectrums used in the Bugbee studies, was that there was inadequate coverage of the photosystems action spectra to draw conclusions that would relate to real world conditions (sunlight/broad spectrum white light/high ppfd). I can expand more on this idea if you’d like.
I agree with you that plants have evolved to utilize most of the sunlight spectrum, and that (overly simplified) a photon is a photon.
Obviously spectral quality/flux will effect the balance/efficiency of both PS I & II and all the accessory pigments, as well as photomorphology.
But keeping in mind that we as cannabis growers are typically looking for the highest yielding dry weight of flower, as well as the highest cannabinoid content, what is the best spectral balance/flux levels to achieve those goals? I’m pretty sure that question has yet to be answered.
I’m glad my posts have at least been amusing to you. I’m not a scientist, nor do I have any higher education regarding plants, light , or really anything related to growing. I’m just a hobbyist who likes to read to gain a better understanding of cause and effect in the grow room, as well as as trying to optimize the growing space/environment.
If I make a mistake or misunderstand something, just let me know as I’m here to learn, share, and better understand how to grow the most dank of buds.
With all of that said, here is a link to a study about the effects of supplemental FR light (730nm at different flux levels) to a background of broad spectrum white light (Cree 3500k 90CRI). Basically what Bugbee should have done in their study, IMO. This study was done on Cannabis in 2022, and at least “their” results culminate just about all of the talking points I’ve been trying to make in this thread. Not saying that these results are conclusive or the end-all solution. But the results are along the lines of what I would expect based on my own personal tests, results of others from the forums, and countless hours of reading through studies and about plant physiology, and why I ask the questions that I ask. Enjoy.
cdgmoney250
Well-Known Member
Here’s the juicy parts from the study for those who don’t want to sort through 60 something pages.
Spectrums used
A yield reduction would obviously be a negative outcome for any producer especially considering we did not see any significant differences in cannabinoid or terpenoid content. If more samples had been sent off for analysis, the author suspects there would have been a significant reduction in cannabinoid content. Based on the samples that were analyzed and the observed leaf senescence, a reduction in cannabinoid content would be likely.
Spectrums used
A yield reduction would obviously be a negative outcome for any producer especially considering we did not see any significant differences in cannabinoid or terpenoid content. If more samples had been sent off for analysis, the author suspects there would have been a significant reduction in cannabinoid content. Based on the samples that were analyzed and the observed leaf senescence, a reduction in cannabinoid content would be likely.
Rocket Soul
Well-Known Member
Sorry, reading this back myself after finishing; its a pretty long and rambly thing, i dont blame anyone for not getting my point, its almost the definition of tldr...
I skimmed the study a bit, enough to recognize having read it before and remember it and what i thought about it; i may have missed something so might be wrong. But here we go:
The problems i had with it was the following: it uses a base spectrum of 90cri which is already somewhat rich in far red. Second thing: it tests for something that almost no lightmaker does: adding only far red to a white spectrum. Its like far red on far red, with no red added below 680.
If i understood shade avoidance correctly: its not really far red that causes it: its the ratios of red to far red that is key. Adding only far red will increase that ratio and thus increase shade avoidance syndrome. But what we see in most lights with far red added is that its actually a red supplement with both 660 and 730nm in a ratio where 660 out weighs 730. Most of the time in ratios of about 3-4 to 1, red to far red ratio. If we check standard white spectrums we see that these ratios of red to far red is really similar to what we get in standard white. So while youre adding far red youre still maintaining similar ratio of red to far red.
Another thing to keep in mind is that shade avoidance syndrome decreases tolerance to high light intensity. Would the decrease in yield of plants suffering from SAS be related to decreased tolerance to light intensity, with the knock on effect of lower photosynthesis or would it be related to morphological effects of SAS, as in a plant who believes its living in shade simply diverting growth potential from flowers towards longer and stretchy stems? I dont know and i dont even know how youd construct that experiment.
With cannabis its always hard basing yourself on only science as the grower will generally try to grow as well and as much as they can. While in a study the grower will try their utmost to make the two or more test conditions to be as similar as possible in order for validity of the experiment. Those two situations are not the same, in our grow we are free but biased agents (we will allways try to grow as best we can) while in an experiment we try to avoid that. Two situations that arent the same and i dont think we can just assume that the results of an experiment based on a totally hands off approach (no adjusting the grow once it started) is going to be the same as a hands on, do whatever you can to grow as well and as much as you can.
My own conclusion or maybe more of a hunch:
Spectrum will have more influence the lower the light intensity, both on yield and on morphological change. As intensity increase the influence of spectrum diminishes and intensity is more important for yield. Up to a point; when we come up towards the limit of how much light we can give to a plant before it starts getting saturated or whatever we call the process that make it hard to grow at +1000 ppfd. At this point spectrum starts having more importance again but not really by itself: at this point the spectrum is important by facilitating higher light tolerance, allowing us to reap the benefits of the light intensity. I wouldnt be surprised if the study mentioned above would get different results if we did it at 100ppfd, 500ppfd as in the study, or say 1200ppfd, while maintaining the ratio of standard white light and far red the same. But again, this is just my hunch, please dont ask me for references.
Also there seems to be some processes in plant physiology that seems to be dependant on relative values, as in percentage of red/blue/green in the spectrum. But other processes seems to be dependant on absolute values(iirc the study correctly it was about stomata aperture, blue light and added co2 but not sure) : not how much of each color in relation to eachother but an absolute value, as in once you have a ppfd of blue light of say 100ppfd the plant would start reacting and open the stomata and increase transpiration. This while at 50ppfd of blue light you wouldnt get half the amount of stomata aperture. Like the plant needs a specific value to trigger the reaction, not a percentage value. Why is this important? It means you may have different results studying one process at 400ppfd and 800ppfd even if the spectrum was kept the same, that 400ppfd would not give you half the reaction as 800ppfd. So each study may not be able to give general conclusions from at all types of light intensities. Im not saying i can prove this but it is my impresion from reading whats probably too many papers online. So i think its really easy to get stuck in arguments about spectrum where infact two sides may be equally right just basing themselves on differing grow conditions. Its a big mess tbh. The more you read and you try to understand the more you see patterns. But also the more you see the limits of scientific method applied in the real life; the conclusions from one paper are valid for a very certain specific set of conditions which we will never really recreate in our own grow, due to its specificity and due to the fact that when we grow we try to grow as best as we can, not as consistent to a set of experimental conditions.
cdgmoney250
Well-Known Member
I’ll try to keep this short considering I’ve been writing novels just to try to share my perspective on things.
I had to touch up on it, but it looks like shade avoidance is primarily a function of R:FR ratios as well as total Blue/ B:G ratio. But R:FR is the main antagonist it seems.
For our discussion purposes, it would have been nice had the study been done using say a 3500k (80CRI) that didn’t have as much red in the spectrum. That said, it’s a very similar format to the Bugbee study, as well as others, regarding adding FR wavelengths to a control spectrum. I just think that the spectrum used in the 2022 Tennessee study, more resembles a grow spectrum than the controls used in the Bugbee studies. While true their isn’t any supplemental deep red added, I appreciate that fact just for informational purposes regarding supplemental FR to broad spectrum light. In my opinion, most of the reason that grow light manufacturers add supplemental DR (660) to their fixtures, is because they are using “Electrically Efficient” spectrums like 3500k (80CRI) or 3000k/5000k (80CRI). These spectrums lack high levels of DR/FR altogether, which is why supplemental RED/FR is likely necessary to achieve a more natural expression from the plant and increase photosynthetic efficiency.
I had to touch up on it, but it looks like shade avoidance is primarily a function of R:FR ratios as well as total Blue/ B:G ratio. But R:FR is the main antagonist it seems.
These are more or less the same conclusions that I have also come to. The “best” spectrum for the plant is likely dynamic and based off things like spectral quality/distribution, flux levels, light angle, plant species, and phenotype. But, like you mentioned, once the light levels reach saturation the plant will be looking for the most efficient way to deal with any excess energy (light/heat) while reducing photoinhibition. I believe this is where where green/yellow light really deliver in terms of whole plant photosynthesis, not only deeper into the lower canopy but deeper into the leaf tissue as well.
Rocket Soul
Well-Known Member
Blue/green ratios is something we never really talk about, but also an important measure. By what mechanism would this determine SAS, please link cause i really find it interesting.
Blue and green both have their own reactions in the plant. The effect of blue on morphology is shorter internodes and and smaller leaves, and some cellular stuff. Note that the blue reaction looks the opposite of what happens in SAS. Heres the kicker, green reverses the effect of blue light. Depending how the science determined that B/G ratios influence SAS it may be true but it may also be that B/G ratios seems to influence SAS by reversing the opposite of SAS. I hope im clear enough, i have the feeling im not always the most clear and concise writer. Also, im sorry, i realize my error in asking for source when i dont provide one myself. Im a messy reader and student, good at memorizing something when i feel like i understood it but bad at remembering where i read it. Im sure KP has some references to material.
cdgmoney250
Well-Known Member
@Rocket Soul THIS study talks primarily about R:FR ratios, which are essentially phytochromes in the active (Pr) or inactive state (Pfr). This article also touches on Crytpochrome blue light response and B:G ratios to determine shade avoidance.
www.ncbi.nlm.nih.gov
To my understanding, high proportions of Green light and FR light in the lower canopy will cause the chloroplast to change their ratio of Clorophyll- a:b to produce more Chlorophyll-b, which changes the action spectrum of the lower canopy to absorb more Cyan, Green, Yellow and Orange wavelengths. These wavelengths have lower absorption in the upper canopy and have a higher likely hood of being reflected, or transmitted to the lower canopy.
VVV- This article talks primarily about green light and photosynthesis, but also talks about the B:G ratio regarding shade avoidance responses and stomatal stimulation (I think). There were so many I’ve read through recently.
https://academic.oup.com/jxb/article/68/9/2099/3857754?login=false
Shade Avoidance - PMC
The presence of neighboring vegetation modifies the light environment experienced by plants, generating signals that are perceived by phytochromes and cryptochromes. These signals cause large changes in plant body form and function, including ...
www.ncbi.nlm.nih.gov
To my understanding, high proportions of Green light and FR light in the lower canopy will cause the chloroplast to change their ratio of Clorophyll- a:b to produce more Chlorophyll-b, which changes the action spectrum of the lower canopy to absorb more Cyan, Green, Yellow and Orange wavelengths. These wavelengths have lower absorption in the upper canopy and have a higher likely hood of being reflected, or transmitted to the lower canopy.
VVV- This article talks primarily about green light and photosynthesis, but also talks about the B:G ratio regarding shade avoidance responses and stomatal stimulation (I think). There were so many I’ve read through recently.
https://academic.oup.com/jxb/article/68/9/2099/3857754?login=false