New Grower Cannabis and its response to light (a discussion about leaf lift)

Ok guys, i am in a chatty mood this morning and i wanted to gather some fresh information for the soon to come Art of The Auto section.

During my years of growing i have noticed a phenomenon in my plants that i could never really explain other than pure health and response to the light that they were growing under, and that is leaf lift. You see it after the lights come on and they stay that way all day, as if they are praying to the light that they are under.

Most outdoor growers probably see this more than the indoor guys do but, i think that if the environment is right. Youll see it inside just as much as you would outside. To me i always saw it as the plant activating its suction method of moisture from the soil. Now this is completely my thoughts and there is no scientific evidence behind that but they lift during the day and then as the day progresses they drop and by lights off they are relaxed and down again. I think during that process they are drawing the water they need for the next day, and then buy morning or lights on they are back up to repeat the process.

Most of the time we see this during the start of flower and then all the way through until they are finished. Its something amazing to see and if they are really happy in their homes they really put on the show. Now ive said what i think that the process is FOR but the thing is WHY?? Something has to trigger that movement and i think it has a lot to do with spectrum of the light as well as how much light it is getting. Ive seen it under HPS, MH, and LED so i know that it can be replicated. Its just something awesome to see.

So what are your thoughts AFN?

This is some of the most aggressive i have ever seen of my plants

 

[pop22]

Yet you can see this in plants that clearly are not receiving too much light. I can raise my light to 30 inches and have a ppf of 300 and see this response. I know a little about light avoidance, take that statement literally, lol just a little I've not read in depth in a while ) and I'm not convinced that this is what is happening, at least not in most cases. I even see this response in my greenhouse, and being translucent, the light is somewhat attenuated and almost completely diffused. Yes, it may still be high levels of light or maybe not

I know that, besides changing the orientation of the chloroplasts, the leaves will rotate up to 90 degrees from horizontal. I would think, the plant will expend the minimum energy needed to accomplish the task. I suspect it takes less energy to rotate the leaf than to raise it vertically. Also, it looks to me like increased turgidity. This is merely an observational assessment, I've not looked into this aspect.

I think this plant response we see is more complex than we know. It makes me wish we had more Cannabis specific scientific data across multiple subject. This damned prohibition has put Cannabis way behind in the research curve!

Actually that is valid but not well explained. It is known as "light avoidance" a protective mechanism well known. I am not sure that cannabis leaves "praying" fits that mechanism exactly, but it plays into the process at some point. Our plants are typically well over the saturation point for photosynthetic radiation, and the plant will cool itself by thickening leaves to block some radiation, among other processes in it's tool belt. The Auxin compound is made in the leaves, it is light avoidant, and moves to the shady side of the leaf, this tightens up the petioles so the leaves stand up and you see an increase in transpiration because the increasing photosynthesis requires more water molecules to split and get H atoms for making NADPH and ATP.

If the plant has excess ATP it will slip into light avoidance mode and start storing it for later use and slow down on transpiration

 

[Son of Hobbes]

Yet you can see this in plants that clearly are not receiving too much light. I can raise my light to 30 inches and have a ppf of 300 and see this response. I know a little about light avoidance, take that statement literally, lol just a little I've not read in depth in a while ) and I'm not convinced that this is what is happening, at least not in most cases. I even see this response in my greenhouse, and being translucent, the light is somewhat attenuated and almost completely diffused. Yes, it may still be high levels of light or maybe not

I know that, besides changing the orientation of the chloroplasts, the leaves will rotate up to 90 degrees from horizontal. I would think, the plant will expend the minimum energy needed to accomplish the task. I suspect it takes less energy to rotate the leaf than to raise it vertically. Also, it looks to me like increased turgidity. This is merely an observational assessment, I've not looked into this aspect.

I think this plant response we see is more complex than we know. It makes me wish we had more Cannabis specific scientific data across multiple subject. This damned prohibition has put Cannabis way behind in the research curve!

What kind of people would be able to better answer that question? I'm 100% game to approach anyone in the industry to come on and talk with us about some of these subjects (and most people are surprisingly willing to talk about this stuff if they are approached; nerds love nerding out when there are other nerds there to nerd with, ya know?) -said as an ex D&D dice-tosser.

 

[Rev. Green Genes]

I know that, besides changing the orientation of the chloroplasts, the leaves will rotate up to 90 degrees from horizontal. I would think, the plant will expend the minimum energy needed to accomplish the task. I suspect it takes less energy to rotate the leaf than to raise it vertically. Also, it looks to me like increased turgidity. This is merely an observational assessment, I've not looked into this aspect.

I think this plant response we see is more complex than we know. It makes me wish we had more Cannabis specific scientific data across multiple subject. This damned prohibition has put Cannabis way behind in the research curve!

It is very complex. Every system interacts with others in strange feedback loops; and in surprising ways. The key player in this Auxin, it effects every aspect of growth and is absolutely playing all leaf systems at once before also having effects by way of it's absence in roots and shoots. Turgidity, yes, another part to play in this. Turgor pressure is up with increased transpiration and I'm not sure which one causes the other. I used to know. It seems like turgor also has to do with opening and closing of stomata

What kind of people would be able to better answer that question? I'm 100% game to approach anyone in the industry to come on and talk with us about some of these subjects (and most people are surprisingly willing to talk about this stuff if they are approached; nerds love nerding out when there are other nerds there to nerd with, ya know?) -said as an ex D&D dice-tosser.

Please! I live for this stuff.

 

[Rev. Green Genes]

chloroplast movement in Elodea



here is the overall picture in a chloroplast

 

[The Iconoclast]

Phototropism is not 'growth' towards the light, it's bending towards the light. The side of the cells that don't get the light become less rigid and are able to change their shape causing the plant to point towards the light. Changing shape is not 'growing'. That's my understanding of the situation.

 

[Tony21]

What kind of people would be able to better answer that question? I'm 100% game to approach anyone in the industry to come on and talk with us about some of these subjects (and most people are surprisingly willing to talk about this stuff if they are approached; nerds love nerding out when there are other nerds there to nerd with, ya know?) -said as an ex D&D dice-tosser.

That would very, very cool man, People from Apogee, Osram, Asentek, Cree, universities and such
https://www.wur.nl/en/Research-Results/Themes/theme-food-production/photosynthesis.htm

 

[Flipper]

Interesting thread, thanks.

 

[MrOldBoy]

Ok, I’m still left confused about all this. I have 2 Chrystal Aurora Autos that is growing from beans I got from New420Guy Seeds. These 2 plants spent 10 days under a 4 bulb T5 fixture with 6500K bulbs running 24/0 and about 3”-4” above them. They started in 16oz solo cups filled with FF Happy Frog soil nixed with FF Light Warrior seed starter soil and served only distilled water with myco added to it. They looked like this when I went to transplant them......

View attachment 942761 View attachment 942762

Then, I went to transplant them into 10 gallon grow bags with Happy Frog soil on the top half and FF Ocean Forest on the bottom half of the bag. I watered the 2 plants prior to transplant with distilled water with 1/3 strength House & Garden Root Excelurator Gold mixed in. I remove the bottom of the cups with a razor plate and make skits up the side. Then, I drop the cups I to a home made to fit them perfectly , complete a couple of the slices in the cup and pull the remnants of the cup out of the soil - a virtually stress free transplant method. I did the transplant about 2hrs before dark. This was their first night outside and they were in a partially shaded spot to give them some protection from the scorching sun here. The following morning I went to check on them and found them “praying” but otherwise looking great. They have been growing well but they remain in that praying stance 24hrs a day. It kinda freaked me out and I found this thread hoping to determine if they’re adjusting to outdoors OK. I think that they are but I’m still not sure; and I damn sure don’t u derstabd why they’re suddenly doing this when they were looking like a photo perfect indica under the fluorescents.

Here’s how they look today......

View attachment 942763 View attachment 942764

So, ARE my 2 girls fine? What’s causing them to do this suddenly?

Yes absolutely fine .... they are beautiful specimens ..... mine looked same at that age, good luck with grow and nice handling of those transplants .....

New to thread, thnaks for your posts .... here’s a girl that has prayed 24/7 and she looks great and is forming buds ..... PAR readings were around 400 and now she has grown a lot, she’s 33 days old in pic .... anyway grown a lot and was under 5000k first 25 days and now 4000k and next week I exchange lights and she’ll be at 3000k ..... Light is on a rail ..... registers PAR at 900 last night and I think she can handle more .... other plants are running 500-600 PAR (PPFD) .....

Gotta tell ya all, there’s a lot of smart folks here at AFN and I’ve gotten a good education .... Thanks AFN.

Sam’s Crack 33sih day’s old

Strawberry Nugs. 33ish days old

 

[autoguy]

Ok guys, i am in a chatty mood this morning and i wanted to gather some fresh information for the soon to come Art of The Auto section.

During my years of growing i have noticed a phenomenon in my plants that i could never really explain other than pure health and response to the light that they were growing under, and that is leaf lift. You see it after the lights come on and they stay that way all day, as if they are praying to the light that they are under.

Most outdoor growers probably see this more than the indoor guys do but, i think that if the environment is right. Youll see it inside just as much as you would outside. To me i always saw it as the plant activating its suction method of moisture from the soil. Now this is completely my thoughts and there is no scientific evidence behind that but they lift during the day and then as the day progresses they drop and by lights off they are relaxed and down again. I think during that process they are drawing the water they need for the next day, and then buy morning or lights on they are back up to repeat the process.

Most of the time we see this during the start of flower and then all the way through until they are finished. Its something amazing to see and if they are really happy in their homes they really put on the show. Now ive said what i think that the process is FOR but the thing is WHY?? Something has to trigger that movement and i think it has a lot to do with spectrum of the light as well as how much light it is getting. Ive seen it under HPS, MH, and LED so i know that it can be replicated. Its just something awesome to see.

So what are your thoughts AFN?

This is some of the most aggressive i have ever seen of my plants

I would also add this ,

ATP/ADP cycle is a important factor in the quantity of energy stored at night for use during the day,...



Just adding 1 hour of sleep will boost the times it last( phototropism), plants that run out of energy still do photosynthesis...just without energy or enthusiasm...

 

[Waira]

good stuff! This came up elsewhere, so I'll copy my post to here as well,... excellent video's too!

...." I can't remember where, but I read that this angling of leaves is usually about making minor adjustments to light intensity.... Think of the leaf as the solar panel it is, and how directly, squarely it faces the light to get the maximum exposure possible; the best posture for this is with the rays hitting straight on, no angle at all,... conversely if it's a bit too much, in the leaves' case, altering the face angle so as to make the light hit more obliquely will reduce the sheer intensity striking it; the sharper the angle, the less directly (squarely) the light hits,.. this affects the heat absorption as well of course, and all the implications for VPD, etc., associated with that.... We experience this ourselves every day, dawn and dusk right, so called "weak" sunlight.... color spectrum changes then too but that's another topic altogether!
....So is the common pre-sunset/lights out drop in petiole posture that looks like over/underwatering symptoms (it's not, leaves stay same shape, it's the petioles only that "relax"), which was sorta explained by AutolowRyder, which I now frikkin' forget where...... I wanted to ask him more anyway, so I'll PM him to see if he can expand on this,.. but it's some sort of physiological "gear-shifting" response very basically put...."