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Author Topic: Necrotic tissues and color changes in graft joints  (Read 10493 times)

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Offline robinast

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Necrotic tissues and color changes in graft joints
« on: Monday, 05 August 2013 - 08:14:12 »
When regrafting from Pereskiopsis, I, more often than not, notice necrosis in graft joint - even in case when the graft looks healthy and has grown pretty well. Non-necrotic color changes are present as well - but not as often. Do you have the same experience?
I regrafted about 30 plants from the Pereskiopsis stock and NONE of them was without any necrosis in graft joint. I wonder if this is common - or due to my conditions (winter temperatures in my greenhouse are lower than optimal for quite a lot of species, incl Pereskiopsis, and I do not water my plants about 6 months...)
The following photos are from three Astrophytum asterias plants, all having grown nicely and healthy looking. One of the plants had only a few necrotic spots (not seen on the photo) and a strong reddish coloring. The actual diameters of the cuts are 2.6...3.4 cm.

Lower cuts:


Higher cuts:


Closer photos (a few necrotic spots now seen on the third plant's cut as  well):


« Last Edit: Monday, 05 August 2013 - 08:25:59 by robinast »
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline danskibsted

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Re: Necrotic tissues and color changes in graft joints
« Reply #1 on: Monday, 05 August 2013 - 08:29:50 »
Hi Harri,
I see this on around 5% of my astro/ario on pereskiopsis grafts.
When I graft digitostigma's, I see this problem on nearly all plants. I have no clue what causses this...

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #2 on: Monday, 05 August 2013 - 08:37:22 »
5%? Then you're a lucky man! As I wrote, I have 100% in case of plants kept overwinter in the greenhouse. I do not remember how about the plants regrafted before they go dormant. Have you noticed this also in case of any other temporary rootstock? It seems to me that the Selenicereus hybrid I use, has this problem as well - but not so sharp. I'll regraft some plants from the Selenicereus hybr. rootstock soon and I'll keep an eye on it.
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #3 on: Monday, 05 August 2013 - 10:14:10 »
Necrosis in Selenicereus/A. asterias graft joint. Plant had not grown already about two years - though had never lost turgor.

Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #4 on: Monday, 05 August 2013 - 11:07:44 »
Discocactus crystallophilus on Selenicereus stock (nicely growing):


Discocactus nigrisaetosus on Selenicereus stock (nicely growing):


Discocactus nigrisaetosus on Selenicereus stock (not growing and loosing turgor):


Ah, do you see the mistake I've made here with these plants? I have to say that actually, it's been a rule rather than an exception with. :-[ Time to change the way I treat the grafted plants! And I wouldn't have noticed it at all if I had not planned to make photos and post them here on the forum...  ::)
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline andrea.a

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Re: Necrotic tissues and color changes in graft joints
« Reply #5 on: Monday, 05 August 2013 - 12:20:20 »
Today and yesterday I regrafted 20 Arios (different species and cultivars) from Pereskiopsis to Echinopsis. I noticed around 50% had that problem you are talking about.
Before regrafting I, little by little, cut away all the brown and hard tissue. It was also difficult to cut with a sharp blade.
These graftings were never kept at lower temperature than 18°C.
The strange thing is that there was no corrispondence between brown spots and growth: some of the biggest and healthy looking plants had the biggest spots.

Many people talk about suberification of the tissue between scion and some stock, above all Pereskiopsis. I read abous Opuntia compressa to be one of the best stock because it never creates this hard tissue.
 Now I have some O. compressa, I'll try as soon as they will be big enaugh.

It is hard not to use Pereskiopsis for seedlings graftings, results are great! I was just thinking to start regrafting before, when scion is no bigger than 1 cm.

Andrea.

Offline danskibsted

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Re: Necrotic tissues and color changes in graft joints
« Reply #6 on: Monday, 05 August 2013 - 14:40:20 »
5%? Then you're a lucky man! As I wrote, I have 100%

Sometimes I regraft older pereskiopsis grafts, and I do not see more brown spots on these compared to the young ones... 2 weeks ago I regrafted some 4 year old horizonthalonius from pereskiopsis to trichocereus, and they were all nice and green on the inside.
I'm wondering if this could have something to do with the way you sterilize your equipment before you make the seedlinggraft?

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #7 on: Monday, 05 August 2013 - 15:21:19 »
I'm wondering if this could have something to do with the way you sterilize your equipment before you make the seedlinggraft?
Well, I think I work very clean, sterilizing blade with alcohol after EVERY cut. And if the problem were in sterility, the grafts just wouldn't take and start rotting, I think. And the 1st year's growth is good or very good (I usually regraft only on the second year).
But what I've made wrong all the time, I guess, is that I let shoots of rootstocks grow after the first winter. Initially, I remove them very thoroughly - but after the scion is growing well and is pretty big already, I do not pay much attention to the shoots. Yes, finally I do remove them indeed(and use for propagation) - but it's not uncommon that I let them grow up to, say, 10 cm long. Now, if you look at the last pictures closer, you see that necrosis appears above and only above the shoots of the rootstock. Principally, it could easily be that it's just the other way around and shoots emerge because of this necrosis - but I do not think so. This way or another, from today on, I'll not let the shoots of rootstock grow any more.  :)
Would be interesting to make an experiment and graft something not very valuable to Pereskiopsis or/and Selenicereus. Say, (2x)120 grafts. And then (after every two month) to cut 10 of them into pieces. This way, the dynamics of developing necrosis could be observed during two years... But who has 120+ rootstocks for wasting this way? At least I don't! :)
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline Simon

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Re: Necrotic tissues and color changes in graft joints
« Reply #8 on: Monday, 05 August 2013 - 15:30:06 »
Interesting thread.
I find this a lot in my pereskiopsis grafts too. It seems that as long as there is some healthy vascular system growing through the necrotic layer then the scion grows very well regardless.
When a graft is made there is always a necrotic layer of cells in stock and scion because some cells are cut through. The graft union forms and becomes functional when meristem cells in the vascular bundle of stock and scion de-differentiate into callus cells and grow through the necrotic layer. The callus cells then re-differentiate as they divide to become the type of cells that make the new vascular system connecting stock and scion. This is actually why you have to align the vascular bundles of stock and scion when grafting, because this is where the most meristem cells capable of de-differentiation into callus and re-differentiation into vascular tissue types are located in plant stems.

I think that in grafts with stocks that have fleshy stems the necrotic layer gradually gets absorbed or slowly grown out wards as the graft-union widens till it becomes that bark like stuff you see in that area sometimes. In the case of pereskiopsis the union is very narrow and widens very little over time so maybe the necrotic layer becomes trapped within the graft union. It could also be something to do with genetic incompatibility between stock and scion or maybe even a physical incompatibility because the scion wants to grow fleshy and thick at the union and the stock wants to grow narrow and woody. This would be particularly true of a species like Digitostigma that wants to grow thick down to a tap root. And I confirm Dan's observation that it is very common with Digitostigma.
One last thing is the pink tissue, I have seen a lot of that as well and I don't think it is necessarily graft related cause I have seen it in Ariocarpus that have been grown own root from seed. Looking at you photos I now think it is probably something to do with the plant trying isolate the infection. I had been wondering for a long time what caused that pink tissue.
Robinast, all your posts are very interesting, good to have you on the forum. I don't think that leaving the shoots is to blame, although it could make it worse, but I have seen this on grafts that I took care to remove the shoots from. Also I agree with your point that it is not caused by unsterile grafting because I am very careful too and I still get a lot like this.
« Last Edit: Monday, 05 August 2013 - 16:19:19 by Simon »

Offline Carlo & Daniele

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Re: Necrotic tissues and color changes in graft joints
« Reply #9 on: Monday, 05 August 2013 - 16:53:49 »
hello guys! really interesting 3d!
We met too this problem, but not in high %. Could it depend also on humidity and the place you keep the grafts immediately after graftings?
We are carefully too with sterilization (we use peroxide for it), but we noticed we have generally less problems with winter graftings than with summer grafts. Then it occurs more with digitostigma as you said and ariocarpus too, less common with myriostigma plants.

Then another question, the vascular tissue on ariocarpus; many times when you cut, it is a mixture of scion and rootstock (peresk for example), when you regraft it on a permanent stock you cut lower (where you can find mixed tissue, pink parts and so on) or do you cut the ario a bit higher, where you can find a more differentiated tissue (almost all ario tissue)?
Carlo & Daniele

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #10 on: Monday, 05 August 2013 - 17:13:43 »
I find this a lot in my pereskiopsis grafts too.
Do you use also some other species as a temporary rootstock? If yes, do you observe the same effect? I see it on my Selenicereus grafts as well.
It seems that as long as there is some healthy vascular system growing through the necrotic layer then the scion grows very well regardless. 
Yes, this seems to be true: these dead areas seem not to be dangerous as far as the vascular bundle still functions. There seems not to be evident correlation between the amount of necrotic tissues and graft's growth.
I think that in grafts with stocks that have fleshy stems the necrotic layer gradually gets absorbed or slowly grown out wards as the graft-union widens till it becomes that bark like stuff you see in that area sometimes.
Would be extremely interesting to compare Pereskiopsis and f.e some Opuntia (vascular system of which is very different) as a rootstock then...

I also think that at least partly, the necrosis we observe is due to some physiological incopatibility. Actually, it's just a miracle how succsessful the grafts are in the Cactaceae family! Is there at least one specias seedlings of which can't be succsessfully grafted onto Pereskiopsis? I haven't heard about it...  :)
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #11 on: Monday, 05 August 2013 - 17:22:21 »
Could it depend also on humidity and the place you keep the grafts immediately after graftings?
No idea actually... Young seedlings' grafts I try to keep always in close to 100% humidity. And I observe the problem after overwintering - as I regraft only on the second year...
Then another question, the vascular tissue on ariocarpus; many times when you cut, it is a mixture of scion and rootstock (peresk for example), when you regraft it on a permanent stock you cut lower (where you can find mixed tissue, pink parts and so on) or do you cut the ario a bit higher, where you can find a more differentiated tissue (almost all ario tissue)?
It occurs also f.e in case of Astrophyms or Aztekiums, so I think it's just a common problem. While regrafting, I always remove any necrosis I notice and if ever possible, also the mixed tissues. Sometimes it means that the graft is only a few mm thick...  :)
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline Carlo & Daniele

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Re: Necrotic tissues and color changes in graft joints
« Reply #12 on: Tuesday, 06 August 2013 - 01:51:20 »
While regrafting, I always remove any necrosis I notice and if ever possible, also the mixed tissues. Sometimes it means that the graft is only a few mm thick...  :)

Yes we do the same but not always...and well it's true that you can leave only few mm to graft.
It would be interesting to know if leaving or not leaving the mixed tissue could affect the frost resistance of the stock+scion in winter, for example while regrafting from peresk to harrisia (that has a better behaviour).
Carlo & Daniele

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #13 on: Tuesday, 06 August 2013 - 06:40:50 »
Some more photos. All the plants were growing normally. Initially, I thought about re-rooting them with a short piece of rootstock - but in the light of this thread, I regrafted them instead.

Astrophytum asterias on Echinopsis (Trichocereus) bridgesii (the dark spots on the upper part of the first photo are merely a debris, not necrotic changes in the plant's tissue):



Astrophytum asterias on Harrisia bonplandii:


Astrophytum asterias on Harrisia bonplandii:
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

Offline fanecchissimo

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Re: Necrotic tissues and color changes in graft joints
« Reply #14 on: Thursday, 08 August 2013 - 18:34:13 »
i think alcool can't kill most fungi spores. but i think the problem is not sterility!

Offline bouldering

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Re: Necrotic tissues and color changes in graft joints
« Reply #15 on: Monday, 12 August 2013 - 01:08:36 »
Does anyone have rooted specimens made from peresk. grafts? How are they after few years? I grafted some OOIBO this spring and I assumed I will simply root them after two years with some peresk cut off from the stock. Now I see it can cause more trouble than I thought.

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #16 on: Monday, 12 August 2013 - 13:08:29 »
Does anyone have rooted specimens made from peresk. grafts? How are they after few years?
Well, about ten years ago or so, I re-rooted several, maybe 6...8, A. asterias cv grafts with a short Pereskiopsis stock. The plants did not grow much bigger and by now, none of them has survived. The Pereskiopsis simply died and so the graft as well. Thus, I would not recommend Pereskiopsis as a permanent rootstock. Other may have different experience, at least I have read/heard about grafts that live on Pereskiopsis stock for years and years.
Some pictures from my collection:
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Offline hans

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Re: Necrotic tissues and color changes in graft joints
« Reply #17 on: Tuesday, 20 August 2013 - 04:26:06 »
could hebbben with rootstocks that are getting cut year on year. making
this phenomenon is also known to seedling rootstocks?

Greetings Hans

Offline Carlo & Daniele

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Re: Necrotic tissues and color changes in graft joints
« Reply #18 on: Tuesday, 03 September 2013 - 01:18:12 »
a plant found today:

Carlo & Daniele

Offline robinast

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Re: Necrotic tissues and color changes in graft joints
« Reply #19 on: Tuesday, 03 September 2013 - 05:15:34 »
Luckily, this can be regrafted...
Some pictures from my collection:
http://e-aiand.com/kollektsioon/index.php

 

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