Questioning Peter Adam's theory on natural dwarfing

[bonsai barry]

In his book "The Art of Flowering Bonsai," Peter Adams states that "By placing bonsai in the sunlight, the shortening effects of the ultraviolet rays on plant growth can be used." (p. 7)

and

"Good air circulation 'exercises' the tree and ... this has a slight dwarfing effect." (p. 7)

I've never heard that sun or wind could dwarf a tree, in fact, I doubt that it is accurate. Can anyone substantiate?

 

[buddhamonk]

I guess both will cause the plant to grow more and isn't it what we want to do. We don't want to dwarf our trees

 

[Alain BERTRAND]

I've never heard that sun or wind could dwarf a tree, in fact, I doubt that it is accurate. Can anyone substantiate?

UV dwarfism is something well proved in mountains. I 'd guess that at low altitude, increased exposition to sunlight would rather mean increased growth for most trees (if water is not liminting).

 

[jk_lewis]

Sunlight will reduce leaves; dunno about the "exercise" though on a slim trunk, it MAY help thicken it slightly.

 

[bonsai barry]

UV dwarfism is something well proved in mountains. I 'd guess that at low altitude, increased exposition to sunlight would rather mean increased growth for most trees (if water is not liminting).

Interesting. I'd like to find a source for this information. It's not that I doubt you, but I work as a naturalist at high elevations, and I've never read that info before. If its true then I'd like to incorporate it in my week-long back packing trips when I talk about high elevation environments.

The plants and shrubs are naturally smaller in these regions but I've always attributed it to:
1) A short growing season (usually between six and eight weeks in the High Sierra... probably six to eight days this year!)
2) The natural selection of genetically smaller plants that are favored in an area of limited soil and resources.

If anyone can provided sources to the ultraviolet rays and plant dwarfism, I'd be grateful.

 

[bonsai barry]

I did some online research which suggested that utraviolet light might have a small effect on stunting growth of some plants (it seemed mostly to effect annuals):

Source 1
Both plants and phytoplankton vary widely in their sensitivity to UV-B. When over 200 agricultural plants were tested, more than half showed sensitivity to UV-B light. Other plants showed neglible effects or even a small increase in vigor. Even within a species there were marked differences; for example one variety of soybean showed a 16% decrease in growth while another variety of the same soybean showed no effect [R.Parson]. An increase in UV-B could cause a shift in population rather than a large die-off of plants . (http://www.nas.nasa.gov/About/Education/Ozone/radiation.html)


Source 2
Dr. Brent Pemberton has found that exposing plants such as impatiens, tomatoes and cucumbers to ultraviolet B, (UV-B) treatments for a few hours slows their foliar growth and stem length without reducing color or other favorable characteristics.
"Simply put, it acts as a growth regulator and stunts them somewhat, but with bedding plants this may be desirable," said Pemberton, who is based at the Texas A&M University Research and Extension Center at Overton. (Writer: Robert Burns (903) 834-6191,d-burns@tamu.edu Source: Dr. Brent Pemberton (903) 834-6191,b-pemberton@tamu.edu)

Source 3
Conclusions/Discussion The pea pods from the UV Blocked environment were also the heaviest and had the highest number of peas per pod. A surprising result was that some of the pots in the Control Group environment produced no peas. Also, a mold developed on the plants in the UV Light Blocked environment. This is probably because ultraviolet light is necessary for the production of vitamins which inhibits the mold growth. The plants in the UV Light Blocked environment were likely unable to produce the vitamins to stop the growth of the mold.
http://74.6.117.48/search/srpcache?...a&icp=1&.intl=us&sig=JqxIUowpqLuYGuwXXeFRKg--

My apologies to Mr. Adams. It appears that ultraviolet light does impact growth .... somewhat.

 

[Alain BERTRAND]

I'd like to find a source for this information. It's not that I doubt you

It seems you are pretty much right when doubting and I must thank you for that.
Although there is a wealth of research papers fact that increased UV radiations decreases plant growth in general (see this a synthetic presentation), I haven't been able to find any paper attributing part of mountain dwarfism to increased UV radiation.

I 'd swear that I am not the inventor of the concept of "UV induced mountain dwarfism" and that I must have read it in somewhere which does not exclude the fact that the author could have presented as proved knowledge something that was just an hypothesis ???
In any way, it is much safer to modifiy my answer to :

" Plant growth reduction by UV radiations is well demonstrated. I 'd guess increased exposition to sunlight would rather mean increased growth for most trees (if water is not limiting)."

Sorry for the mistake.

Edit :Bonsai Barry posted his second post on the subject while I was writing my answer.

 

[Bonsai Nut]

I did some online research which suggested that utraviolet light might have a small effect on stunting growth of some plants (it seemed mostly to effect annuals):

Interesting that phytoplankton is mentioned. I have read a number of papers on coral bleaching and the acclimatization methods of various marine invertebrates. Size is not really relevant (since it is impossible for corals to change size) but TYPE and direction of growth is impacted. Additionally, many pigments in marine invertebrates have the ability to block UVR. The more UVR you are exposed to, typically the more pigment that is generated. In the case of many corals, they become darker and/or more colorful. Humans have the same response

 

[treebeard55]

I have heard David DeGroot, curator of the Pacific Rim Collection, state that light at the red end of the spectrum promotes legginess, blue-end light promotes compactness. (He didn't use the term "dwarfing.) David, I believe, is careful about his plant science -- better be, really, to keep the job he has! I believe him.

 

[jk_lewis]

Interesting. I'd like to find a source for this information. It's not that I doubt you, but I work as a naturalist at high elevations, and I've never read that info before. If its true then I'd like to incorporate it in my week-long back packing trips when I talk about high elevation environments.

The plants and shrubs are naturally smaller in these regions but I've always attributed it to:
1) A short growing season (usually between six and eight weeks in the High Sierra... probably six to eight days this year!)
2) The natural selection of genetically smaller plants that are favored in an area of limited soil and resources.

If anyone can provided sources to the ultraviolet rays and plant dwarfism, I'd be grateful.

I doubt that anyone can.

But another reason for small trees at elevation is wind, ice and snow.

 

[Bill S]

Less sun = bigger leaves, as they enlarge to try to get enough of the sun to promote the photosynthesis, so wouldn't the converse fit your question?? More sun = smaller leaf.

 

[rockm]

The more intense the exposure to UV, the more compact some plants become. Doesn't have to happen at higher elevations. If you doubt it, grow a trident maple in shade, compare leaves, shoots and leaf internodes with one grown in full sun....

http://www.ehow.com/list_6716266_effects-ultraviolet-light-plants_-growth.html