phytochrome manipulation

click80 · Jan 20, 2011

Cytochromes are protein molecules that harbor a chromophore, a color-absorbing molecule. Depending on the wavelength of light striking the plant surface, the phytochromes are converted between different states or forms. When the phytochromes receive red light (660nm) they become the Pfr type, which is active and allow flowering to proceed. If far-red light (730nm) is detected the phytochrome becomes the Pr type. The Pr type is a biologically inactive form and so flowering cannot proceed. An indoor gardener can use this principle to initiate flowering even in a light cycle of 14 or more hours. During the dark period of a plant’s life, they can be given a brief pulse of red light. This changes the Pr type into the Pfr form and allows flowering to begin. Interestingly, these same phytochrome proteins play a crucial role in seed germination.

anyone know if this works on cannabis...and if so where can a light be bought that has that narrow a range(660nm)

MTgrower · Jan 30, 2011

I have been using Kessil bloom boosters 70% 660 nm and 30% 635nm as supplemental lighting to my 1000W Sun Pulse 3K flowering bulbs with good results. I have not played with far red pulses to minimize dark period, but yes, the stuff about phytochrome is true with marijuana.

dextr0 · Jan 30, 2011

I found this where this guy explains some of it....what are u planing to do click if u dont mind me asking.

http://www.invalid.com/advanced-mar...cycle-phytochromes-florigen-manipulation.html
Florigen isnt well understood. But we do know it is effected by the type of phytochrome. Phytochrome is a pigment/flourophore that changes its type depending on whether it recieves red or infrared light. Red light converts phytochrome to the version that stops flowering. IR makes phytochrome the flowering type. Also naturally phtochrome will convert from the nonflowering to flowering type on its own. Exposed to any kind of light or not. This is why long dark periods promote flowering. All sativa and indica strains have this phytochrome complex. But diff strains need less darkness to flower so if you bred the right strains you could get a strain that would flower OPTIMALLY at 14 hrs. You can get most plants to flower at 14 hours light but not optimally, they take much longer.

You could also get a IR light/emitter. Then right when your lights turn off you could turn on the IR. This would speed the conversion of phtochrome from Nonflowering type to flowering type. You would only need to expose them to IR for 2 hours +/- (you need to experiment). Doing this I imagine you could run close to 20 hrs light.

Finally you could just breed in ruderalis strains. They dont depend on phytochromes to flower, they use another mechanism that works off of age. This is what makes the lowryders autoflower under 24hr light. The disadvantage is that ruderalis is very low yielding and the trait is passed on to lowryder relatives.

Hope all that typing helps, Lamp

click80 · Jan 30, 2011

thanks..

MTgrower said:
I have been using Kessil bloom boosters 70% 660 nm and 30% 635nm as supplemental lighting to my 1000W Sun Pulse 3K flowering bulbs with good results. I have not played with far red pulses to minimize dark period, but yes, the stuff about phytochrome is true with marijuana.

good im very interested in this....

gudkarma · Jan 31, 2011

me too... very very interested.

i'll check that RIU thread.

dextr0 · Jan 31, 2011

click80 said:
Cytochromes are protein molecules that harbor a chromophore, a color-absorbing molecule. Depending on the wavelength of light striking the plant surface, the phytochromes are converted between different states or forms. When the phytochromes receive red light (660nm) they become the Pfr type, which is active and allow flowering to proceed. If far-red light (730nm) is detected the phytochrome becomes the Pr type. The Pr type is a biologically inactive form and so flowering cannot proceed. An indoor gardener can use this principle to initiate flowering even in a light cycle of 14 or more hours. During the dark period of a plant’s life, they can be given a brief pulse of red light. This changes the Pr type into the Pfr form and allows flowering to begin. Interestingly, these same phytochrome proteins play a crucial role in seed germination.

anyone know if this works on cannabis...and if so where can a light be bought that has that narrow a range(660nm)

dextr0 said:
I found this where this guy explains some of it....what are u planing to do click if u dont mind me asking.

http://www.invalid.com/advanced-mar...cycle-phytochromes-florigen-manipulation.html
Florigen isnt well understood. But we do know it is effected by the type of phytochrome. Phytochrome is a pigment/flourophore that changes its type depending on whether it recieves red or infrared light. Red light converts phytochrome to the version that stops flowering. IR makes phytochrome the flowering type. Also naturally phtochrome will convert from the nonflowering to flowering type on its own. Exposed to any kind of light or not. This is why long dark periods promote flowering. All sativa and indica strains have this phytochrome complex. But diff strains need less darkness to flower so if you bred the right strains you could get a strain that would flower OPTIMALLY at 14 hrs. You can get most plants to flower at 14 hours light but not optimally, they take much longer.

You could also get a IR light/emitter. Then right when your lights turn off you could turn on the IR. This would speed the conversion of phtochrome from Nonflowering type to flowering type. You would only need to expose them to IR for 2 hours +/- (you need to experiment). Doing this I imagine you could run close to 20 hrs light.

Finally you could just breed in ruderalis strains. They dont depend on phytochromes to flower, they use another mechanism that works off of age. This is what makes the lowryders autoflower under 24hr light. The disadvantage is that ruderalis is very low yielding and the trait is passed on to lowryder relatives.

Hope all that typing helps, Lamp

This confuses me. Anyone else. Thoughts?

MTgrower · Feb 2, 2011

dextr0 said:
This confuses me. Anyone else. Thoughts?

Interruption of the dark period with red light will prevent flowering because it converts Pr into Pfr. Pr levels need to hit a critical level in order to initiate flowering (photoperiod dependent flowering).

At lights out, the Pfr converts spontaneously back to Pr over the course of about two hours.

Far red light converts Pfr back to Pr, so a pulse of far red will eliminate that two hour period of spontaneous conversion, shortening the dark period by two hours and allowing two extra hours of light.

According to Rosenthal, a flash of Far red light instantly changes the phytochrome. No need to run them for any period of time.

I hope that helped.

Seamaiden · Feb 2, 2011

What's the spectral difference between red and infrared? It would be very helpful if the people spoke in terms of specific wavelength.

dextr0 · Feb 2, 2011

I was saying that those two articles that me and click posted were in conflict because they were saying exactly the opposite (i think) about pr and pfr light. I just wanted to know what was right.

click80 said:
When the phytochromes receive red light (660nm) they become the Pfr type, which is active and allow flowering to proceed. If far-red light (730nm) is detected the phytochrome becomes the Pr type. The Pr type is a biologically inactive form and so flowering cannot proceed.

dextr0 said:
Red light converts phytochrome to the version that stops flowering. IR makes phytochrome the flowering type.

610 - 720 nm This is the red band. Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (promotes flowering and budding)
720 - 1000 nm There is little absorption by chlorophyll here. Flowering and germination is influenced. At the high end of the band is infrared, which is heat.

I found this in a book, u can see it here:http://books.google.com/books?id=8a...e&q=phytochromes and pf and pfr light&f=false

Advanced biology by Michael Kent

Photoperiodism and the detection of night length
Photoperiodism requires a mechanism for detecting the length of darkness. The best-known candidate for this job is a pale-blue light-sensitive protein called phytochrome. It exists in two interconvertible forms: Pr which absorbs red light (light with a wavelength of 660nm), and Pfr which absorbs far-red light (light with a wavelength of 730nm). Phytochrome is synthesised in its Pr form. Experiments with specific wavelengths of light show that Pr is converted into Pfr when exposed to red light, and that Pfr is converted back into Pr when exposed to far-red light or when in darkness. During the day, there is more Pfr than Pr because sunlight has a higher proportion of red light than far-red light. During the darkness of night, Pfr is gradually converted back into Pr. Thus the relative amounts of the two forms of phytochrome could indicate day length. It is thought that the balance between the two forms of phytochrome controls flowering in short-day and long-day plants. A build up of Pfr could stimulate flowering in long-day plants, whereas in short-day plants, Pfr could inhibit flowering.

Seamaiden · Feb 2, 2011

I had to go back and forth, but I read them as saying the same thing--that a shift in spectrum towards 730nm will induce transition of Pr into Pfr.

Is this how you're interpreting them?

Wait... fuck, rereading it, now I'm not sure I understand what I'm reading.

dextr0 · Feb 2, 2011

They are saying diff things.

http://books.google.com/books?id=8a...e&q=phytochromes and pf and pfr light&f=false
This is our answer though.
[I]Phytochrome is synthesised in its Pr form[/I]. Experiments with specific wavelengths of light show that Pr is converted into Pfr when exposed to red light, and that Pfr is converted back into Pr when exposed to far-red light or when in darkness.

gudkarma · Feb 3, 2011

MTgrower said:
Interruption of the dark period with red light will prevent flowering because it converts Pr into Pfr. Pr levels need to hit a critical level in order to initiate flowering (photoperiod dependent flowering).

At lights out, the Pfr converts spontaneously back to Pr over the course of about two hours.

Far red light converts Pfr back to Pr, so a pulse of far red will eliminate that two hour period of spontaneous conversion, shortening the dark period by two hours and allowing two extra hours of light.

this is what i was thinking.

this would allow you to flower plants faster & finish plants in less time.

i would love to have the chance to run 10 to 12 week strains in my set up built for 9 weeks max.

i wonder how this effects buds & bud development?

click80 · Feb 5, 2011

thanx

MTgrower said:
Interruption of the dark period with red light will prevent flowering because it converts Pr into Pfr. Pr levels need to hit a critical level in order to initiate flowering (photoperiod dependent flowering).

At lights out, the Pfr converts spontaneously back to Pr over the course of about two hours.

Far red light converts Pfr back to Pr, so a pulse of far red will eliminate that two hour period of spontaneous conversion, shortening the dark period by two hours and allowing two extra hours of light.

According to Rosenthal, a flash of Far red light instantly changes the phytochrome. No need to run them for any period of time.

I hope that helped.

sorry...death in fam...ill be home in a few days and will post more...for now here is a link to one source...and its recent 2009 i think...http://cshperspectives.cshlp.org/content/1/6/a001586.full.pdf

and one from zwenger http://www.scribd.com/doc/14571756/The-Biotechnology-of-Cannabis-Sativa

sorry to leave this hangin....my uncles are on the fucking endangered species list...3 in 1 1/2 yrs....thanx for all these replies...i ordered my tissue culture supplies and will be experimenting when i get back...there are applications of the subject of this thread in tissue culture[tc]...

click80 · Feb 5, 2011

its possible

gudkarma said:
this is what i was thinking.

this would allow you to flower plants faster & finish plants in less time.

i would love to have the chance to run 10 to 12 week strains in my set up built for 9 weeks max.

i wonder how this effects buds & bud development?

this research seems to indicate that by manipulating the pfr:pr ratio at the least can help control stem elongation where its not desired ie too control sativa stretch possibly.....

hmmmmmmm

click80 · Feb 7, 2011

dextr0 said:
I was saying that those two articles that me and click posted were in conflict because they were saying exactly the opposite (i think) about pr and pfr light. I just wanted to know what was right.

610 - 720 nm This is the red band. Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (promotes flowering and budding)
720 - 1000 nm There is little absorption by chlorophyll here. Flowering and germination is influenced. At the high end of the band is infrared, which is heat.

I found this in a book, u can see it here:http://books.google.com/books?id=8a...e&q=phytochromes and pf and pfr light&f=false

Advanced biology by Michael Kent

Photoperiodism and the detection of night length
Photoperiodism requires a mechanism for detecting the length of darkness. The best-known candidate for this job is a pale-blue light-sensitive protein called phytochrome. It exists in two interconvertible forms: Pr which absorbs red light (light with a wavelength of 660nm), and Pfr which absorbs far-red light (light with a wavelength of 730nm). Phytochrome is synthesised in its Pr form. Experiments with specific wavelengths of light show that Pr is converted into Pfr when exposed to red light, and that Pfr is converted back into Pr when exposed to far-red light or when in darkness. During the day, there is more Pfr than Pr because sunlight has a higher proportion of red light than far-red light. During the darkness of night, Pfr is gradually converted back into Pr. Thus the relative amounts of the two forms of phytochrome could indicate day length. It is thought that the balance between the two forms of phytochrome controls flowering in short-day and long-day plants. A build up of Pfr could stimulate flowering in long-day plants, whereas in short-day plants, Pfr could inhibit flowering.

yes...you are right...the excerpt i posted has to be a typo? i am sorry for not catchingg it....my thoughts on this are that it has to be a typo...

dextr0 · Feb 27, 2011

Was reading Ed Rosenthal's Marijuana Grower's Handbook today and ran into this:

pg 380.
Jump Starting Flowering

Long periods of uninterrupted darkness are nature's trigger to marijuana to begin flowering. This is measured chemically by phytochrome, which is deactivated by red light. The inactive form is refered to as Pr. In the absence of red light, with a peak at 666 nm (coincidence? I think not*) and effects from about 500-700 nm, Pr drifts into its active form Pfr, over a period of about two hours. This begins at dusk or when the lights are turned off. This transition period, during which Pfr has limited effectiveness, can be dramatically shortened.

Pr is sensitive to far-red light with a peak at 730 nm and is affected in a range of about 700-715 nm. In its presence it changes almost immediately to active form, Pfr. This effect is useful for shortening the two-hour time it takes plants to switch from inactive to active form.

Indoors after the grow lamps are turned off, expose the plants to far-red (730 nm light) which turns the Pr to Pfr much faster and induces flowering within a shorter dark period. You can provide far-red lighting using LEDs or some fluorescents. Far-red light can also be used to restore the active form of the hormone if the dark is interrupted by light. This may ameliorate the consequences of darkness interruption.

Outdoors, you have no control over dawn and dusk, but you can force flower out of season by using far-red lighting to increase the time the plants are under Pfr's flower-inducing influence by two hours. Plants receiving 15 hours of light and 9 hours of darkness react as if they were under a lighting regime of 11 hours of darkness because of the additional two hours of active hormone. Most plants initiate flowering under 11 hours of darkness, which is shortened to 9 after exposure to 730 nm far-red light.

gudkarma · Mar 1, 2011

dextr0 said:
Pr is sensitive to far-red light with a peak at 730 nm and is affected in a range of about 700-715 nm. In its presence it changes almost immediately to active form, Pfr. This effect is useful for shortening the two-hour time it takes plants to switch from inactive to active form.

Indoors after the grow lamps are turned off, expose the plants to far-red (730 nm light) which turns the Pr to Pfr much faster and induces flowering within a shorter dark period. You can provide far-red lighting using LEDs or some fluorescents. Far-red light can also be used to restore the active form of the hormone if the dark is interrupted by light. This may ameliorate the consequences of darkness interruption.

Outdoors, you have no control over dawn and dusk, but you can force flower out of season by using far-red lighting to increase the time the plants are under Pfr's flower-inducing influence by two hours. Plants receiving 15 hours of light and 9 hours of darkness react as if they were under a lighting regime of 11 hours of darkness because of the additional two hours of active hormone. Most plants initiate flowering under 11 hours of darkness, which is shortened to 9 after exposure to 730 nm far-red light.

these three paragraphs are the idea money!

i find this part particularly fascinating : "Plants receiving 15 hours of light and 9 hours of darkness react as if they were under a lighting regime of 11 hours of darkness because of the additional two hours of active hormone"

what i find odd is the rosenthal's tone & his use of conditionals (words like may, might, should).

he is putting it out there ...but really doesn't know the answer.

i'm also wondering if any of this is either universal to all MJ plants or do some strains react better to high Pfr.

Jsän · Mar 1, 2011

gudkarma said:
what i find odd is the rosenthal's tone & his use of conditionals (words like may, might, should).

he is putting it out there ...but really doesn't know the answer.

i'm also wondering if any of this is either universal to all MJ plants or do some strains react better to high Pfr.

Ed goes on to say in the book, that this "technique" still needs a lot of testing, and should be experimented on a controlled basis.
I had the distinct impression that it was relatively new information to him at the penning of the book.

He also brings in the opposite site of the equation.

Pure Blue (400-450nm) inhibits the Pfr/Pr conversion, but not as much as the Red Spectrum. this can be used to our advantage when sexing young plants. The blue light would be used during HALF of a 24/0 veg cycle. ....that is, instead of placing cuttings under a 12/12 cycle. The whole plant is placed under 12hours of veg spectrum (6500k) then instead of lights out, they get 12 hours of 400nm blue light.

The effect is pre-flowering earlier, without a full hormone change. so there is little to no stress to go back to full 24/0 veg. and no cuts to keep track of.
vegging will slow a bit during the 12 hours of blue light... stems will become stockier.

i plan on experimenting with this when my seeds come in. i have very little space to work with.

jack hairy · Mar 29, 2011

any specific brands of ir lights?
anyone ever use any?
so someone could set some lights up to turn on for a couple minutes at dusk, converting pr to pfr, triggering plant to flower, even in the middle of the summer with a 14 light 10 darkness schedule
the plant would see it as 14/12
then be able to flower outdoors in the sunniest time of year, and not have to worry about the late season.
even if you just used it to initiate flowering 2 weeks or a month earlier than usual, i bet it would help a lot of people

Desertboy · Apr 2, 2011

Very interesting thread,

would this

be what I want?

phytochrome manipulation

phytochrome manipulation

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click80

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Jsän

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phytochrome manipulation

phytochrome manipulation

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click80

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Seamaiden

Living dead girl

dextr0

Seamaiden

Living dead girl

dextr0

gudkarma

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click80

click80

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gudkarma

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Desertboy

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