It is shown that blue light-induced stomatal opening is mediated by the blue light

Light Regulation of Stomatal Movement
Plants have evolved multiple photoreceptor systems to monitor light quality, quantity and direction.
It is well known that stomatal morphogenesis is controlled by genetic as well as environmental factors and in general, an increase in light intensity results in an increase in stomatal index and a systemic signal from mature leaves determine the response.43,75–78 Light is perceived by various photoreceptors,79,80 and stomatal movements are regulated by both blue and red light.
The blue-light response of stomata appears to be strongly affected by red light, and the underlying mechanisms in the interaction between blue-light signaling and guard cell chloroplasts were recently reviewed in reference 14.

It is shown that blue light-induced stomatal opening is mediated by the blue light receptor phototropins (PHOT1 and PHOT2) and cryptochromes (CRY1 and CRY2).
81 Recent findings suggest that the light control of stomatal development is mediated through a crosstalk between the cryptochrome-phytochrome-COP1 signaling system and the mitogen-activated protein kinase signaling pathway.
82 Blue light is required for the activation of phototropins, plant-specific Ser/Thr autophosphorylating kinases, and the activated phototropins transmit the signal to the plasma membrane H+-ATPase for its activation.
80,83 Activation of the H+-ATPase is caused by the phosphorylation of a Thr residue in the C terminus with subsequent binding of a 14-3-3 protein to the Thr residue.84,85 Since phototropins are Ser/Thr protein kinases, it might be possible that phototropins directly phosphorylate the H+-ATPase. However, this has been shown not to be the case since it was demonstrated that protein phosphatase 1 (PP1), a major member of the PPP family of Ser/Thr protein phosphatases, mediates the signaling between phototropins and H+-ATPase in guard cells.86 Therefore, ABA is likely to inhibit the signaling molecule(s), including phototropins, PP1, H+-ATPase and other unidentified components.

It has also been suggested that the guard cell response to red light is in part an indirect response to red-light-driven intercellular CO2 uptake in the mesophyll.87 For example, it has been shown that chloroplast-containing guard cells in albino sections of variegated leaves do not respond to photosynthetically active radiation, but are sensitive to blue light and CO2, bringing into question a direct role of guard cell photosynthesis on red-lightmediated stomatal opening in intact leaves.35
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258058/

Any thoughts Beta?

Let's stick to science, not he said-she said.....Please!
shag

(I'll give it one more shot, let's hope this time is different.)

Stomatal opening as a function of spectrum is affected by ultraviolet, blue, green and red wavelengths.

In the case of green that's the reversal of blue light stomatal opening, so green light reduces (narrows) stomatal apertures after blue light increases (widens) stomatal apertures.

Blue light has by far the strongest effect on stomatal opening, it takes a lot more red light to have the same effect as blue light (somewhere around 10x the amount if I recall correctly).

In terms of blue light photoreceptors and effect on stomatal apertures, using the generalized phototropin action spectrum is likely a good route. However, there are specific blue spectrum action spectra for some plants that are used as a generalized action spectrum for stomatal opening.

I have uploaded all the action spectra I wrote about so you can see for yourself what they look like. The blue and green are most accurate, and there are other action spectra to choose from, as well. See the title of each figure to see what it's showing you. [EDIT: I can't seem to find the red light action spectrum of stomatal opening at this moment.]

The blue and green action spectra figure (the first one) shows both spectrum normalized, as does the last figure (phototropin action spectrum).

These are all the stomatal affecting action spectra we're digitizing into our spreadsheet so it computes these values for each light source that is analyzed. So for example, the spreadsheet will help choose a lamp that has greater positive effect on stomatal opening (wider) than another lamp.

Oh yea, nice link I don't think I've read that before.

Oh yea, for full reversal of blue light mediated stomatal opening when there's blue and green light present, by green light, it takes about a 1:2 ratio of blue:green photon flux (if I recall correctly, I have to check my notes).

Good info!
Thank you sir!
Let's try to keep this thread as clean as possible, Please
Or else I will then
No really, it is better clean....NO?

Peace to all!
Buds for all too.
Shag

@ Beta Test Team
So I got to thinkin'!
After tellin' the fire dept. the smoke was only from my ears, and they could all go now.

My thoughts were, I have my eye on a LED light which allows you to adjust red, blue levels ect.
I could turn off everything but blue light apply a foliar spray wait a while and then adjust it back to full spectrum.

Is there a scientific explanation to justify this or is this just a fleeting thought and I should move on?

Thanks Beta, for spending time in my threads!
shag

Well, the idea about opening stomatal apertures is sound (and using red light as well would be fine). But beneficial foliar sprays don't enter leaves by stomata in most all cases, except by humans applying herbicides or some pesticides. However, the cells and pores around the stomata are used by foliar sprays to penetrate the leaf, and using blue and red light may increase the pore swelling, for example.

So in a round about way you do seem to a have a sound hypothesis And testing it wouldn't be too difficult, actually pretty easily (leaf tissue testing post-spraying). I have never read of that hypothesis before, maybe it's novel.

But I would use red and blue light, not just blue. And foliar sprays penetrate leaves over the course of hours and days for most solutes. So those are some other things you should consider. As well as other factors that affect stomatal apertures, including RH, irradiance, plant-water status, CO2, etc.

I have a 400 and 600 watt 7200k metal halide lamps made by Plantmax. The light is very white and blue, and the plants growth rate is just incredible. I've only used them a few times, but compared to HPS which is mostly orange and red, the difference is night and day.

-Funk

FunkBomb said:

I have a 400 and 600 watt 7200k metal halide lamps made by Plantmax. The light is very white and blue, and the plants growth rate is just incredible. I've only used them a few times, but compared to HPS which is mostly orange and red, the difference is night and day.

-Funk

Click to expand...

you should bring them together with red bulbs and really watch the fire works.

Shaggy, in case you didn't see this in the other thread (https://www.icmag.com/ic/showpost.php?p=6720536&postcount=5), you may like this (and click that link, too):

Very little contribution to this thread, nothing in 6 years.