Please dumb down "apically dominant" for me

[It's Kev]

Right, so the tree species isn't really relevant, i think, but i'm trying this out with a bougie and a citrus of some sort (possibly lemon, i found it next to the building and yanked it out a few months ago). The bougie is a really rough and ugly air layer that i scored for super cheap and chose because of its thickness.
So, each of them are trimmed at the top to boost lower growth, but each also has a whip, or taller branch to maintain the health of the tree.
i gotta add a rudimentary drawing or illustration of sorts, lets put that here.


NOW, if i just wire the top part down to be physically lower than the branches that i wanna grow out, is it better for the lower foliage to develop?

 

[nuttiest]

no, neither is better for lower foliage, you bend the branch to get new buds at new apex, which is top of bend. The lower part of bend then becomes sacrifice branch... unless you start to like it

 

[nuttiest]

if you want to strengthen lower branch faster wire it the closest to sun for a while

 

[Shibui]

NOW, if i just wire the top part down to be physically lower than the branches that i wanna grow out, is it better for the lower foliage to develop?

Bending the long apex down lower than other branches should help those lower branches grow stronger. I've done this a few times and it does seem to make a difference.

 

[Potawatomi13]

Apically dominant tree sends energy to most Sunward located part of tree to generate greater height but less energy to parts spreading sideways. Non AD trees spread sideways instead of mostly upward. (at least growing under "their" ideal conditions)

 

[leatherback]

Yes it will.

In short, apical dominant; Trees want to grow rall. To reach a tall state, the parts of the tree that are tallest and/or get most sun will get access to most of the resources, causing it to grow the strongest.

 

[It's Kev]

Thanks, it seems like I got the logic right then

My citrus had 2 light green spots yesterday that might only have been in my imagination, but then I rubbed off the new buds on the leader and bent it down. Today there are 7 buds, once the foliage hardens off I’ll chop it to just above that point.
It’s a bit too tall for mame, but it should make a nice little shohin broom one day.

 

[R0b]

Apically dominant means that the auxins produced by terminal bud suppress the growth of lateral buds and shoots. The stronger the apical dominance the more elongation and less ramification you will see.

Apical dominance - Wikipedia

en.wikipedia.org

The effect of bending and growth coming from the highest point is probably more related to phototropism. Where auxin also plays a role.

Phototropism - Wikipedia

en.wikipedia.org

 

[Wires_Guy_wires]

The effect of bending and growth coming from the highest point is probably more related to phototropism. Where auxin also plays a role.

I think it's even more related gravitropism ;-) in the sense that when one shoot senses it's closer to the ground, other shoots sense they're higher up and start growing too.

Gravitropism - Wikipedia

en.wikipedia.org

Apically dominant means that a plant favors(!) apical growth. But that doesn't mean that there's always a need to do anything with that apical growth to produce adventitious growth. Because those adventitious shoots also have an apex, which also compete for nutrients and energy. See sacrifice branches for instance; even though a tree is apically dominant and has a super huge apex, that doesn't mean that the bottom half stops growing. It depends a whole lot on the balance between the two areas.

 

[R0b]

I think it's even more related gravitropism ;-) in the sense that when one shoot senses it's closer to the ground, other shoots sense they're higher up and start growing too.

Gravitropism - Wikipedia

en.wikipedia.org

Apically dominant means that a plant favors(!) apical growth. But that doesn't mean that there's always a need to do anything with that apical growth to produce adventitious growth. Because those adventitious shoots also have an apex, which also compete for nutrients and energy. See sacrifice branches for instance; even though a tree is apically dominant and has a super huge apex, that doesn't mean that the bottom half stops growing. It depends a whole lot on the balance between the two areas.

I don’t think that the budding on top of a sharp bend is due to gravitropism. Light exposure reduces auxin concentration and biosynthesis so the exposed top of the bend will have less suppression of buds.

 

[It's Kev]

I think it's even more related gravitropism ;-) in the sense that when one shoot senses it's closer to the ground, other shoots sense they're higher up and start growing too.

Gravitropism - Wikipedia

en.wikipedia.org

Apically dominant means that a plant favors(!) apical growth. But that doesn't mean that there's always a need to do anything with that apical growth to produce adventitious growth. Because those adventitious shoots also have an apex, which also compete for nutrients and energy. See sacrifice branches for instance; even though a tree is apically dominant and has a super huge apex, that doesn't mean that the bottom half stops growing. It depends a whole lot on the balance between the two areas.

so with the balance thing, thats why the leader points downward to relax a while so the other growth can catch up.

but since it is now budding out where i want it to, i might as well chop off the top bit that i dont need anymore anyway, is that right?

think i'm over sensitive because i've had one too many trees that go "belly up" on me

 

[nuttiest]

so with the balance thing, thats why the leader points downward to relax a while so the other growth can catch up.

but since it is now budding out where i want it to, i might as well chop off the top bit that i dont need anymore anyway, is that right?

think i'm over sensitive because i've had one too many trees that go "belly up" on me

This one will disappoint you as well, citrus are hard to chop like this. This needs to go in a deep pot with organic soil and be vigorous before any cutting, like a whole year or more. Start root reduction when you are 75% there, bonsai pot and soil when you are 90% there.

 

[Wires_Guy_wires]

I don’t think that the budding on top of a sharp bend is due to gravitropism. Light exposure reduces auxin concentration and biosynthesis so the exposed top of the bend will have less suppression of buds.

Do you think there's a lot of difference in light levels, a couple inches apart? I think in sunlight, whole meters might make a difference but a couple inches would not make a difference. Gravity wise a couple inches matters a lot.

so with the balance thing, thats why the leader points downward to relax a while so the other growth can catch up.

but since it is now budding out where i want it to, i might as well chop off the top bit that i dont need anymore anyway, is that right?

think i'm over sensitive because i've had one too many trees that go "belly up" on me

Yes, you can chop off the higher part so that all energy gets directed to the new shoots. But waiting a little longer can't hurt.
From my experience with citrus, it wouldn't have needed a leader anyways. If you chop them hard or let them die from drought (happens indoors too often here in Europe), they usually bud all over.

 

[Paradox]

Apical means referring to or denoting an apex.
The Apex is the very top of the tree.

So apically dominant means the apex of the tree is where the dominant growth will be as stated because trees want to grow tall and do that by growing up out of the apex.
So yes, lowering the Apex below other branches should cause those other branches to take over and become apically dominant in a tree species that is apically dominant

Not all species are apically dominant. Azaleas for example are basally (bottom) dominant

 

[R0b]

Do you think there's a lot of difference in light levels, a couple inches apart? I think in sunlight, whole meters might make a difference but a couple inches would not make a difference. Gravity wise a couple inches matters a

Do you understand what phototropism is and what causes it at a cellular level and how this relates to apical dominance and bud growth?

If so let’s agree to disagree which is more important in driving plant growth. This varies per species and tissue anyhow.

 

[Wires_Guy_wires]

Do you understand what phototropism is and what causes it at a cellular level and how this relates to apical dominance and bud growth?

If so let’s agree to disagree which is more important in driving plant growth. This varies per species and tissue anyhow.

I do, yes. It was part of my studies and I worked on it for at least six months in a controlled setting. And let's agree to disagree then.

 

[Deep Sea Diver]

Wow, things are getting feisty here, eh? Perhaps we might focus on OP’s question.

Seems to me phototrophism and gravitropism might be too esoteric for the OP’s question to “dumb down apical dominance”.
( Not to say I never engage in such down in the weeds chat )

I’d kinda think just sticking with @Paradox‘s basic thought as a macro view would sum up a decent answer.

Also on the Practical side @Wires_Guy_wires alluded a basic bonsai view to just chop the top. Then let the plant grow out for now and choose favorites to craft a bonsai form once the growth hardens…..

cheers
DSD sends

 

[nuttiest]

Isn't it more like injury response than any of those terms?

 

[It's Kev]

Do you think there's a lot of difference in light levels, a couple inches apart? I think in sunlight, whole meters might make a difference but a couple inches would not make a difference. Gravity wise a couple inches matters a lot.

Gotta agree here, there wont be any at all, since i've been systematically chopping the tree over the last while, the leader that remains grew sideways anyway, and it's a 10inch long twig with some leaves at the end.

@R0b lets not deviate too far, light exposure is a whole new can of worms that i don't wanna open right now, lets stick to the physical altitude of whatever the tree thinks is the top.

My tree is in a deeper pot with nice top dressing for presentation, underneath that it's all organic soil and coffee grounds

 

[nuttiest]

Eeew coffee grounds... I stopped using them in compost because I became convinced they were bad for it, even though there is no reports of such, but have way more veggies that will grow in pure compost now. I use on some of the bonsai and they have invasive tomatos