Study: Sugar demand, not auxin, is the initial regulator of apical dominance

[a senile fungus]

What would be your goal?

Collection of anecdotal evidence

 

[Rocketman64]

Thats what I thought as well but again a newb when it comes to anything other than time release nutes and praying (seems to work for the most part lol). I would really like to to go kind of au natural for the auto's, so by adding some kind of sugar I would think it would help with the all around health of the soil. That hopefully would help the plant get required nutrients without hitting the spot on a regular basis. I just thought the study may explain why some soil growers say they get good results using molasses. Also the enzymes people use in hydro, are they not used to convert dead plant material into sugars? If I'm getting way off topic I'm sorry and just tell me to get the hell off this thread lol.

Check out some information on Mycorrhizal networks if you really want to keep it simple when it comes to soil life. You'll be amazed how easy it is to maintain a proper soil balance with the correct ingredients. Molasses is nice but I prefer it in my cookies!

 

[waterdawg]

Check out some information on Mycorrhizal networks if you really want to keep it simple when it comes to soil life. You'll be amazed how easy it is to maintain a proper soil balance with the correct ingredients. Molasses is nice but I prefer it in my cookies!

I will do that. Thanks! Its unfortunate that growing 6 plants here could get you 6 months in jail! The days of using the garden hose in my back yard are gone

 

[Uncle Ben]

I hope we still have a group of younger people with the same kind of thirst for unanswered questions that my generation has. I suspect they're out there but they currently have their faces stuck in their cell phone worried about somebody's post on Facecrap, in my opinion.

Facebook and Twitter, what a complete waste of time.

Ever watch Water's World on the Bill O'Reilly show? He'll interview youth, the ones you speak of at a beach, political event, street and ask simple questions like, "who is Joe Biden" or "who was our first president", "what does the 2nd Amendment provide for"? Maybe 1 in 10 can answer such basic questions. Then they expect you to give them an answer when they demand it rather than doing some simple research.[/quote]

 

[cannaculturalist]

I certainly didn't post this to troll. I am rather disappointed that the posting of a scientific article would yield such a suggestion. I have better things to do with my time than argue with stoners on the internet. I am just a curious bloke that likes to explore the natural world. I had no expectation that this was going to change anything for anyone, nor should it have changed anyones existing practices if they've already shown to be plenty effective. Nice to see some actual discussion of the science rather than just people hurling shit at each other. Whatever flips your switches.

 

[Thorhax]

Significance

It is commonly accepted that the plant hormone auxin mediates apical dominance. However, we have discovered that apical dominance strongly correlates with sugar availability and not apically supplied auxin. We have revealed that apical dominance is predominantly controlled by the shoot tip’s intense demand for sugars, which limits sugar availability to the axillary buds. These findings overturn a long-standing hypothesis on apical dominance and encourage us to reevaluate the relationship between hormones and sugars in this and other aspects of plant development.

......Our data support a theory of apical dominance whereby the shoot tip’s strong demand for sugars inhibits axillary bud outgrowth by limiting the amount of sugar translocated to those buds.

"A theory". Let's be clear cause some folks tend to rush to conclusions and link this to that. The buds they refer to are not flowers for starts, they are dormant foliar buds which I refer to in my 4 main cola ditty. You take out the apical dominant points and those sugars/auxins/Cuero Gold shots are redistributed, which backs up my never ending preaching that the top, the most active growing part of a plant/tree/shrub is gonna get mother nature's goodies. IAA also plays a strong role.

When it comes to cannabis, there are many varieties that seem to put on good nugget development at lower levels in the shade, which I showed in my "no light" thread.

Moreover, artificially increasing sucrose levels in plants represses the expression of BRANCHED1 (BRC1), the key transcriptional regulator responsible for maintaining bud dormancy, and results in rapid bud release. An enhancement in sugar supply is both necessary and sufficient for suppressed buds to be released from apical dominance.

I never found any reference to how, when, and where sucrose was applied in the study and in what form.

http://www.pnas.org/content/early/2014/04/04/1322045111.abstract

https://www.facebook.com/FESPB.EU/posts/278091662359052

Isn't sucrose a carbohydrate? I know carbohydrates supply the quickest energy... Could this theory show that these quick energy carbs is part of what makes the side branches grow faster. Of course it would obviously be in conjunction with auxin.

 

[a senile fungus]

Isn't sucrose a carbohydrate? I know carbohydrates supply the quickest energy... Could this theory show that these quick energy carbs is part of what makes the side branches grow faster. Of course it would obviously be in conjunction with auxin.

Basically, auxins are a hormone that suppresses, or opposes, axillary bud development. This hormone is produced by the tallest growing shoot tip, or the most "apically dominant."

The traditional school of thought is that the most dominant top was sending down these auxins to the axillary bud sites and suppressing them from growing. This study suggests that it may not be auxins that play a sole role in axillary bud site suppression, but actually that the amount of sugars that are available to each budsite may be what's causing the axillary buds to remain dormant, in conjunction with the hormones. The presence of sugars in an axillary bud site is "sufficient and necessary" to release a budsite from its bind of apical dominance.

This makes sense I think because the main cola is going to be using a lot of sugars and will want to inhibit the other colas from growing so that it can continue to take advantage of having a large portion of the plant's total sugar count to itself. The fact that it is using up a lot of sugars means that there won't be many sugars leftover for axillary buds, and those axillary buds will be suppressed, both by the auxins, but more importantly by lack of available energy.

Basically sugars move faster through a plant than auxins do and so when you top a plant, the signal for the dormant side bud sites to start growing isn't necessarily from the hormone auxin, but from a surge of sugar availability within the plant.



If you feel/see the need to correct me please do... I'd like this to remain productive and educational

 

[cannaculturalist]

I think of it this way; that he apical shoot is growing the most and using up the sugars being produced for shoot development - from the leaves, a portion of which is for roots and he rest of the plant body. So I suggest it is about prioritising the resources and that reduces the supply to the axillary buds to conserve energy. If in ample supply, lateral shooting does occur on its own account in some plants - but surpressed unless the top shoot is damaged, and having an element of redundancy.

So the quest is, what about giving the plant extra sugar to encourage the side shoots? Well, maybe it's not so simple. It would depend on the path ways and whatever controlling mechanisms are involved. If what I pose of a priority of plant resources is correct, then introducing additional sugars to the plant would not necessarily elicit the response of induced branching, again depending on species.

With this kind of research and then the posing of future questions requires one to think in terms of the plant more than just what we can do to fiddle with some process we don't yet fully understand.

 

[a senile fungus]

I think of it this way; that he apical shoot is growing the most and using up the sugars being produced for shoot development - from the leaves, a portion of which is for roots and he rest of the plant body. So I suggest it is about prioritising the resources and that reduces the supply to the axillary buds to conserve energy. If in ample supply, lateral shooting does occur on its own account in some plants - but surpressed unless the top shoot is damaged, and having an element of redundancy.

So the quest is, what about giving the plant extra sugar to encourage the side shoots? Well, maybe it's not so simple. It would depend on the path ways and whatever controlling mechanisms are involved. If what I pose of a priority of plant resources is correct, then introducing additional sugars to the plant would not necessarily elicit the response of induced branching, again depending on species.

With this kind of research and then the posing of future questions requires one to think in terms of the plant more than just what we can do to fiddle with some process we don't yet fully understand.

I think this study helps to show why topping has the effects that it does, ie topping above the second node produces four tops, third node produces six, fourth is eight etc.

I also think, (don't shoot me) that it could explain much of the plant/bud site behavior when we defoliate.

I think this could have many applications and am excited to see more similar research and thought stemming from this.

 

[Thorhax]

I think this study helps to show why topping has the effects that it does, ie topping above the second node produces four tops, third node produces six, fourth is eight etc.

I also think, (don't shoot me) that it could explain much of the plant/bud site behavior when we defoliate.

I think this could have many applications and am excited to see more similar research and thought stemming from this.

Significance

It is commonly accepted that the plant hormone auxin mediates apical dominance. However, we have discovered that apical dominance strongly correlates with sugar availability and not apically supplied auxin. We have revealed that apical dominance is predominantly controlled by the shoot tip’s intense demand for sugars, which limits sugar availability to the axillary buds. These findings overturn a long-standing hypothesis on apical dominance and encourage us to reevaluate the relationship between hormones and sugars in this and other aspects of plant development.

......Our data support a theory of apical dominance whereby the shoot tip’s strong demand for sugars inhibits axillary bud outgrowth by limiting the amount of sugar translocated to those buds.

"A theory". Let's be clear cause some folks tend to rush to conclusions and link this to that. The buds they refer to are not flowers for starts, they are dormant foliar buds which I refer to in my 4 main cola ditty. You take out the apical dominant points and those sugars/auxins/Cuero Gold shots are redistributed, which backs up my never ending preaching that the top, the most active growing part of a plant/tree/shrub is gonna get mother nature's goodies. IAA also plays a strong role.

When it comes to cannabis, there are many varieties that seem to put on good nugget development at lower levels in the shade, which I showed in my "no light" thread.

Moreover, artificially increasing sucrose levels in plants represses the expression of BRANCHED1 (BRC1), the key transcriptional regulator responsible for maintaining bud dormancy, and results in rapid bud release. An enhancement in sugar supply is both necessary and sufficient for suppressed buds to be released from apical dominance.

I never found any reference to how, when, and where sucrose was applied in the study and in what form.

http://www.pnas.org/content/early/2014/04/04/1322045111.abstract

https://www.facebook.com/FESPB.EU/posts/278091662359052

EXACTLY!!!! i think that this study just shows another reason topping works.

 

[Thorhax]

I think this study helps to show why topping has the effects that it does, ie topping above the second node produces four tops, third node produces six, fourth is eight etc.

I also think, (don't shoot me) that it could explain much of the plant/bud site behavior when we defoliate.

I think this could have many applications and am excited to see more similar research and thought stemming from this.

However i do not think that it has something to do with defoliation. it wouldn't make sense for sugars to rush to the big fan leaves.

 

[chuck estevez]

However i do not think that it has something to do with defoliation. it wouldn't make sense for sugars to rush to the big fan leaves.

Actually, the leaves are what makes the sugars, it's called photosynthesis.

Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the sun, into chemical energy that can be later released to fuel the organisms'

 

[cannaculturalist]

Ok well here's a question. If this is describing why topping works, then how might this work in regard to LST, bending the plant to encourage lateral growth. Is this purely a tropic effect or partly related to the auxin/sugar flow?

 

[a senile fungus]

However i do not think that it has something to do with defoliation. it wouldn't make sense for sugars to rush to the big fan leaves.

Actually, the leaves are what makes the sugars, it's called photosynthesis.

Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the sun, into chemical energy that can be later released to fuel the organisms'

There was another study posted on the site which suggested that some larger fan leaves may actually be competing for nutrients with the bud sites. This goes back to the sink or source debate. Leaves are the primary and most efficient and productive location where photosynthesis takes place. If a leaf stops to produce so much, or so efficiently, there will come a time when that leaf will no longer be a source of carbs, and will become a sink. If this is the case, the leaf will be a competitor. So removal of said leaf will not cause net loss of carbs and any energy going into that sink leaf will continue in the ductwork to other parts of the plant.

That study along with this one, for me, suggests that selective removal of leaves (not completely stripping a plant of all leaves) may be a way to redirect plant resources.

I will continue to play around with this idea...

 

[a senile fungus]

Ok well here's a question. If this is describing why topping works, then how might this work in regard to LST, bending the plant to encourage lateral growth. Is this purely a tropic effect or partly related to the auxin/sugar flow?

I would think that it is a relationship between sugar availability and auxins suppressing the lower lateral shoots.

When you LST you might change which shoot is actually the tallest. The tallest will typically be dominant and use the most sugars. Also, by spreading the branches out you are opening the plant up, possibly allowing more sugar production by leaves and therefore changing sugar concentrations within the plant. Maybe this change in sugar production allows the axillary buds to have more access to sugar and to leave their dormant state and become competing colas...

Note: This is all speculation and rambling. I may not actually know what I'm talking about...

 

[Uncle Ben]

This is a shot of my grapevines March of this year breaking bud. They are pruned/topped to what's called Vertical Shoot Positioning or VSP. It takes years to produce properly selected fruiting spurs on the permanent cordon arms (and I'm still tweeking)....we're talking spurs at least a fist apart so there's some room for air movement and light into the canopy, about 2-4 buds per spur, about 5-7 spurs per 3' arm, denubbing the stuff that pops daily that comes off the side and below the arms, etc. Not for the faint of heart.



.....and this is what happens come harvest.



Once you master topping and pruning, you rule the world!!!!

(sorry, couldn't resist)

 

[Rocketman64]

So, in the harvest pic- all the foliage we're seeing originated from the spurs you have spaced apart on the cordon arms? Forgive my ignorance but are spurs also producing the buds for the grapes themselves or do they come later from shoots off the spurs? Thanks for the info YouTwitFace.

 

[neo12345]

we're talking spurs at least a fist apart so there's some room for air movement and light into the canopy,

(sorry, couldn't resist)

Why would you need to get light in to the canopy?

 

[Uncle Ben]

So, in the harvest pic- all the foliage we're seeing originated from the spurs you have spaced apart on the cordon arms? Forgive my ignorance but are spurs also producing the buds for the grapes themselves or do they come later from shoots off the spurs? Thanks for the info YouTwitFace.

Yes, all that from the spurs. It gets to be a jungle and anything over 6.5' I top. I also have to trim the laterals before netting. Every time I cut, it induces more foliage from the axis of the branches. I try to keep it neat and clean. Some just let the foliage go all over the place, but they don't net either. Many resort to getting cases of shotgun shells and eliminating the bird pop.

I've had what's called 'bull canes' come from those spurs, we're talking shoots up to 10' long.

The spurs have winter dormant buds. Budbreak is in spring and the flowers/fruit is abundant along the new shoots about 6" above the cordon wire.

 

[Uncle Ben]

Why would you need to get light in to the canopy?

As detailed in previous posts, to increase fruit and wine quality. Do some research on wine grapes.