Callus Formation in Clones

Rubisco456

Member
Straight up: What is your opinion on the importance and the role that callus formation plays in the cloning process?

Do you use callus formation as an indicator of successful clones?
Do you care about callus formation?
Do you induce its formation?

I’ve been doing a lot of research on plant anatomy and cell culture for a grow that I’ll be working with and in my time working with the grower I’ve heard them say that the callus formation is the signal that they wait for to make the call that the clone is going to make it. I really like that idea because the callus will seal off the wound and can give rise to roots but I’m curious to know what the general community thinks about this technique or if it’s a widespread practice?

For those that are unfamiliar with the term Callus - callus, In botany, soft tissue that forms over a wounded or cut plant surface, leading to healing. A callus arises from cells of the cambium. When a callus forms, some of its cells may organize into growing points, some of which in turn give rise to roots while others produce stems and leaves. Thus a callus may be capable of regenerating an entire plant.
Here is a picture of callus in plant cell culture:
Callus in Cell Culture.png

Plant cells demonstrate the ability to be totipotent that is: a single cell in a plant can give rise to a whole other plant if given the correct hormones - unlike animals cells that are LOCKED into their roles (I know people are messing around with inducing some mammalian cells to be pluripotent) this is how plant cell culture is possible.
 

waterproof808

Well-Known Member
Technically, Dont all cuttings form a callus before rooting? It goes from root bumps to callus to roots.
I think what you are specifically referring to is the new IG trend started by "Slownickel" where he leaves the cut end outside of a root plug and a callus forms over the plant wound.
 

PJ Diaz

Well-Known Member
Unless it's tissue culture, I care more about roots than callus formation. Callus is made up of undifferentiated cells, meaning that they can form any part of the plant, roots or shoots.
 

StareCase

Well-Known Member
... Do you use callus formation as an indicator of successful clones? ...
I look at the tops of the clones cause those places that are healing from the cuts are below the level of the medium and I can't see them. Once the cuttings start showing new growth up top, the rooting was successful.
... Do you care about callus formation? ...
Nope. Trying to clone in plain water at first, I have seen the lower parts of the stem get little white bumps as the roots emerge. But now I can't see them cause they are buried in the Pro Mix. I care about the cuttings reaching towards the light after 14 days in the dome.
... Do you induce its formation? ...
Nope. Cloning is 30 minutes of actual effort followed by 20,130 minutes of leaving things alone. If I start opening my dome lid to try and do anything, I reduce the high humidity, drop the internal temperatures and really slow down the cloning. It's set and forget here.
 

waterproof808

Well-Known Member
I’m pretty sure OP is referring to this new trend on instagram where people let the end of their cut stick out through the medium and it makes a callus that supposedly seals the cut end to supposedly make it harder for pathogens to enter. FCDACF69-209A-4874-BE64-7CB2F2B64C09.jpeg
 

Star Dog

Well-Known Member
I wouldn't argue the point but I'm sure I see roots forming without calluses?

Iirc the callous only forms when the clones are taking longer to root?

Unless the little warty bits are considered a callous my clones have rooted before a callous forms.
Eta... I've checked a pic I'd say no callous.
_20221027_003811.JPG
Maybe I'm missing something?
 
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weedstoner420

Well-Known Member
Huh, I always thought it was spelled "callous" with an O, and could function as a noun or an adjective. But it turns out "callus" is the noun form, and "callous" is the adjective form...
Anyway, I'm another one who clones in dirt, so I really don't know what's going on down there until I see roots poking through.
 

mudballs

Well-Known Member
I wouldn't argue the point but I'm sure I see roots forming without calluses?

Iirc the callous only forms when the clones are taking longer to root?

Unless the little warty bits are considered a callous my clones have rooted before a callous forms.
Eta... I've checked a pic I'd say no callous.
View attachment 5218043
Maybe I'm missing something?
All roots on clones start as a callus/callous. They were just super tiny on urs.
 

Rubisco456

Member
I’m pretty sure OP is referring to this new trend on instagram where people let the end of their cut stick out through the medium and it makes a callus that supposedly seals the cut end to supposedly make it harder for pathogens to enter. View attachment 5218009
That's a great picture of callus in action, the question for me is how you induce roots from that?

I did not know this was a trend in IG - I really don't go on there much. Is this guy in a hydronic system in rockwool?
 

Rubisco456

Member
I wouldn't argue the point but I'm sure I see roots forming without calluses?

Iirc the callous only forms when the clones are taking longer to root?

Unless the little warty bits are considered a callous my clones have rooted before a callous forms.
Eta... I've checked a pic I'd say no callous.
View attachment 5218043
Maybe I'm missing something?
You bring up a good point about how small the callus can be, I find it hard to see finer structures on the stems when the clones are in EZcloners/wet with gelled rooting substances.

Do you think if I removed the clones from an EZcloner and dried them out to observe for small callus formation they wouldn't be too stressed out?
 

waktoo

Well-Known Member
Straight up: What is your opinion on the importance and the role that callus formation plays in the cloning process?

Do you use callus formation as an indicator of successful clones?
Do you care about callus formation?
Do you induce its formation?

I’ve been doing a lot of research on plant anatomy and cell culture for a grow that I’ll be working with and in my time working with the grower I’ve heard them say that the callus formation is the signal that they wait for to make the call that the clone is going to make it. I really like that idea because the callus will seal off the wound and can give rise to roots but I’m curious to know what the general community thinks about this technique or if it’s a widespread practice?

For those that are unfamiliar with the term Callus - callus, In botany, soft tissue that forms over a wounded or cut plant surface, leading to healing. A callus arises from cells of the cambium. When a callus forms, some of its cells may organize into growing points, some of which in turn give rise to roots while others produce stems and leaves. Thus a callus may be capable of regenerating an entire plant.
Here is a picture of callus in plant cell culture:
View attachment 5217946

Plant cells demonstrate the ability to be totipotent that is: a single cell in a plant can give rise to a whole other plant if given the correct hormones - unlike animals cells that are LOCKED into their roles (I know people are messing around with inducing some mammalian cells to be pluripotent) this is how plant cell culture is possible.


"Exogenous application of auxin and cytokinin induces callus in various plant species. Generally speaking, an intermediate ratio of auxin and cytokinin promotes callus induction, while a high ratio of auxin-to-cytokinin or cytokinin-to-auxin induces root and shoot regeneration, respectively (Skoog and Miller, 1957)."





 

PJ Diaz

Well-Known Member
What ppm IBA for clones is everyone using these days? I've just been using the cheap 1000ppm stuff for ever, but thinking about getting 3000ppm instead.
 

OldMedUser

Well-Known Member
What ppm IBA for clones is everyone using these days? I've just been using the cheap 1000ppm stuff for ever, but thinking about getting 3000ppm instead.
I had to look but the powder I use is 1000ppm or 0.1% but the gel I use is 4000ppm or 0.4% IBA. I tend to dip the dry stem into the gel then shake off excess then a dip in the powder and giving that a tap to knock off excess. I have tried just one at a time and nothing at all and still get 100% 9 times out of 10 tho the ones with nothing tend to take a few days longer. I screen fresh Promix HP through a 1mm mesh metallurgical screen, (same as mosquito screen), for my medium to make sure I have good stem contact with the moist medium. Poke a hole with a chopstick or something so the goop doesn't get rubbed off as I plant the stem then press it in from the sides with the blade on my little swiss army knife with a few squirts of water to seal it all up.

On the left is fresh unscreened.

ProMix03.jpg

Tried an experiment with extra holes in the little cups. Don't do that as they dried really fast and needed water every day even in the dome.

Clones010.jpg

To get back to topic I did see lots of callus forming and the roots coming out of them when I tried my new at the time DIY cloner. I left them in there when it was warm and root rot started but they grew fine in pots of promix.

Rooted08.jpg

:peace:
 

Rubisco456

Member
I was under the impression that it was important to stop pathogens from entering the clone and not as much for rooting. I could be completely off base though
Yes you are right that callus is generated to heal a wound, the tissue it's self is essentially a clump of un-differentiated cells from around the wound site. With the cells being undifferentiated they can be come basically any plant tissue they want, and in the case of the cut clones, roots arise from the callus that forms at the site of the cut. The reason I posted this was to get a sense of how important people treat callus formation as an indicator of clone health and if it means that they'll get strong rooting form those clones that have callus.
 

Spindle818

Well-Known Member
Yes you are right that callus is generated to heal a wound, the tissue it's self is essentially a clump of un-differentiated cells from around the wound site. With the cells being undifferentiated they can be come basically any plant tissue they want, and in the case of the cut clones, roots arise from the callus that forms at the site of the cut. The reason I posted this was to get a sense of how important people treat callus formation as an indicator of clone health and if it means that they'll get strong rooting form those clones that have callus.
Well I started letting the bottom of my clones stick a half inch out of the bottom of my cubes. They do callus up pretty quick, but the roots seem to sprout from higher up on the cutting and not from the actual callus. I’m not too sure about the correlation
 
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