Cleaning up a wound, the discussion continues…

After sharing the results of this experiment, I received an interesting comment from an individual whose horticultural knowledge I respect and seek at times. Here is the essence of his comment, which made me consider the fact that I didn’t consciously create a “control” in the experiment.

Brian,
Very interesting blog post today…

I saw a Lindsay Farr video a few years ago where he contended that recutting the suberized tissue accelerated the healing response. While it seems plausible, it never seemed to do anything beneficial for me. I am assuming you were influenced in an analogous way. What I don’t understand about why this could possibly work is that the first thing the cambium actually does is to reform the callus and then xylem grows behind the cambium and bark ahead.

Cutting away the suberized tissue leaves the a cambium exposed to dessication. Putting something over that prevents the dessication until the new (albeit thin) callus is formed, which takes only 3 or 4 days. I most often use a wad of sphagnum, or just polyethylene film, like you did. I’ve left it for months in a few cases and just a few days in others and never was impressed that there was any difference. I certainly saw no results like you showed in your blog today.

Ethylene is known to stimulate accelerated cambium growth and cutting certainly would stimulate some ethylene production (damage response). I’ve tried ethylene treatments to no avail, so I am truely dazzled by your result.

Soooooo, I must be missing something.
1. How many similar results with wound closure have you had like this?
2. Do you have any ‘heads up’ comparisons against similar wounds that weren’t under damp sphagnum or ‘cut paste’?
3. Can you offer any explanations about what I am missing/overlooking/not doing correctly?

Regards,
J.

Here are my answers to the questions:
3. I can’t explain what’s going on under wraps the way J does, so I thought readers would appreciate the description of events he provided above.

1. This was truly an experiment to see what would happen. Years ago I took a Kathy Shaner workshop, and we made some big, 3″ cuts on a large camellia. Kathy put some damp rags on the cuts and told me to keep them wet, that the humidity would keep the callus rolling. It did work to some degree, but camellia has really thin bark and heals very slowly. I didn’t have a “control” cut to compare it with in this case either.

2. Just by chance, I did get a photograph that showed some cuts on this Chishio maple made in April 2013. I sealed it with cut paste for the year, but it had fallen off by March 2014. Here is a shot of the cut made in April 2013:

2015/01/img_2444.jpg
And the same cut in January 2015; after 2 full growing seasons:

2015/01/img_2441.jpg

The uncovered callus has advanced about 3/16″ around the perimeter over 2 seasons’ time, while the covered cut advanced around 3/4″ in less than half of the time. Far from scientific, I’ll admit, but certainly worth repeating to test.

2015/01/dscf7182.jpg
The more I look at this tree, the more tempted I am to cut it down to about 1.5″ tall and get some real taper and movement in this puppy…hmmm…

Thanks for reading; comments always appreciated.

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6 thoughts on “Cleaning up a wound, the discussion continues…

  1. Well, I can certainly comment on one item J has mentioned Brian.
    Cutting of tissues certainly produces ethylene, but it’s not the hormone responsible for the creation of Callus tissue. I’m still in the infancy of my research into this in practice, but what you would need to promote callous tissue on a freshly cut wound is auxin, cytokinin, and Gibberlin. The ethylene in the case of cutting a branch is more a signal hormone that then produces these other hormones in meristematic cells, which then produce callus. The research that has been done on cloning plants from single callus cells or tissue cultures is most relevant, as the hormones that cause the callus tissue to multiply is very relevant to our work. Here’s a good overview, but better papers are available online.
    http://en.m.wikipedia.org/wiki/Callus_%28cell_biology%29

  2. Another thing this research can be extremely useful for is creating buds from callous tissue. As the situation stands currently, normal practice for bonsai will not produce buds from callus tissue, under any circumstances. But through this type of hormone research, we could produce buds from wound tissue, not only accelerating growth of the callus, but giving us branches in places where we would have to graft.

  3. These hormones are all available online, and I would encourage anyone with a scientific bent to experiment with them. What we talk about when we talk about wound closure and speeds is Callus formation and the rate at which cells divide to produce more tissue. Clearly moisture retention is one thing that promotes cell division in Callus culture, and that’s the entire purpose of cut paste. Other treatments that have shown to be effective are tinfoil, so it’s likely that callus cells also divide faster in a no light environment. But that’s about all we have In Bonsai culture. Figuring out the ratios of Auxin to Cytokinin to signal for rapid division at the cellular level would change the game wholly.

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