Regarding the emerson effect as described: the activation of photosystem 1 and 2 at the same time; if we roughly describe photosystem 1s action spectra as being outside standard white leds spectrum (Violets and n-uva and far red, <450nm and >700nm) is there a s possibility to see a sorta emerson effect if only adding uva/violets? Has anyone studied this?
nice, just yesterday I thought I drop you a line for that info you've mentioned before. I looked, but couldn't find. It seems like the whole UVA situation is less scientifically available than UVB, and the fact there are so many different phytoreceptors there doesn't make it easier...
Well, I guess you know more than me about this, so I'd welcome it if we'd combine our resources/knowledge.
I do not know anything about UV exzitating PS I. When I decided to learn more "beyond PAR" I picked IR as first and decided to only venture into UV once I had this task done. But as always, things get bigger and out of hand. I'm currently learning up on the various forms of Phytochrome Far-Red - especially the photo
stable-form and its reaction. Can increased stretching translate to increased budmass once the stretch is over?
I'd have a few very interesting reads for you, but unfortunately it's in german. Mostly books about photobiology or plant physiology. There are some studies, but these can only be used to support a general statement. I'm away from using studies to form a generalized opinion as I've seen now too many conflicting results on the same matter. For example, there is a famous study around which informs us that Nitrogen in flower will decrease THC! BS!!!! This study was debunked by a follow-up study, correcting the mess. But went unnoticed.... :/
I do also feel that the EE is greatly misunderstood. Because of Wikipedia -.-
The increase in photosynthetic activity is only a side-effect - primarily mentioned @ popular sources because it's been the information to proof that there are 2 separate photosystems at large. This is caused by a RED-SHIFT (on paper) enabling the usage of FR photons into photosynthesis at the presence of PAR photons. The reason is:
(I need to make this short otherwise it would fill pages)
PSII + its antenna LHCII is much larger in chlorophyll-content than PSI + its antenna. PSII also contains more accessory pigments. The differences in absorbance are around cyan, red/orange and darkred.
The difference in cyan is left out as Carotenoids only deliver about 30-50% of its energy to the Reaction Center (RC), the rest is wasted, but even if one would want to use it it would be too narrow 5-10nm even for monochromatic diodes. Problem: Temperature can change the absorption spectra a little. Heat equates to more red-shift in these cases, as the phononic or vibronic energy increases, also the Pi-electron orbitals widen + interconnect with one another....
Outside in nature plants encounter a changing spectrum day by day, and the 2 photosystems can be understood as a means to optimize its light harvesting abilities.
If PSII is increasingly exzitated over PSI (for example, under white light diodes) then about 30% of the LHC II -antenna can wander towards PSI, and support it with energy. This process takes about 1-4 hours to complete (this is a huge problem as it can completely goof up the results of studies trying to analyse photosynthesis rates)
If we now saturate PSI with enough photonic energy then the LHCII can stay @ PSII - and then the max amount of netto photosynthesis can be reached. But it takes a huge amount of photons <680nm for this, as you can see from the generalised spectrum of the sun. The 3-4 special darkred super-chlorophyll-macromolecules which sit close to the RC p700 of PSI absorb around 700-740nm with peaks 710 718 etc so the 730nm diodes will not fully touch them....
The good news is that PSI cannot be over-excited as this will only lead to an electron-backflow via the cyclical-electron-transport-mechanism.
The FR photons can also subtract heat fromt he system (shield its RC from excessive heat @ high umol rates) but can also lead to a decrease in initial (top) leaf PS rates, but overall PS + biomass acquisition is increased. The addition or combination of green + FR light drives sub-canopy PS rates...
Actually I'm writing on a detailed guide about this phenomenom (as the EE is only an "effect") but in order to understand it, one needs to understand the whole photosynthetic process, esp. the Z-schematic and the LH-supercomplexes.
But then these FR photons also act on the Pfr system and some results (biomass, flowering time, ripening) could even be attributed to this stimulus, and not increased PS rates. But who can say what is responsible for what, when it comes to the end-product?
There's a tent, a pot, a seed, and a grower... and something good to smoke in 3 months... but everything in between may just be broscience
I'll upload some sources tomorrow, it's already late here
