Effects of radiation on plant morphology

Speaking of getting out of Dodge- gee wiz, Bill and Mark, you two done beat me to the draw. I was just planning on posting information on the Tradescantia plant family's ability to act as an effective bioassay for radiation. Small world Dodge City. Another good reference is @ Wikipedia:
http://en.wikipedia.org/wiki/Tradescantia

The Wikipedia article presents a nice overview of the Tradescantia family of plants, and its sensitivity to radiation and ability to serve as an effective bioassay for ambient radiation levels.

Actually, both of your informative comments nicely compliment the Wikipedia article. And, guess what, more referencing to research in the Wikipedia article's Reference section:

Ichikawa, Sadao (1972). "Somatic Mutation Rate in Tradescantia Stamen Hairs at Low Radiation Levels: Finding of Low Doubling Doses of Mutations". The Japanese Journal of Genetics 47 (6): 411–421.
The Genetics Society of Japan

Laboratory of Genetics, Faculty of Agriculture, Kyoto University
Abstract:
"Somatic mutation rates from blue to pink were studied in the stamen hairs of Tradescantia ohiensis KU 7 clone, a blue/pink heterozygote, exposed to 100 to 510mR/hr gamma rays or to 12mR/hr scattering radiation. The results obtained supported the previous finding of the sensitive genetic responses of this botanical system, demonstrating that the genetic effect could be detected with this system at a radiation level as low as 3.60R total exposure (also possibly only 0.96R) given at a low exposure rate of 12mR/hr. Pooling the present and previous data, a somatic mutation rate of 3.88 or 3.43×10-4 pink mutant events per hair per R was obtained for gamma-ray irradiation during hair development. The somatic mutation rate calculated for scattering radiation was even higher than this (1.25×10-3). The doubling dose of the somatic mutations at the specific locus was calculated to be 13.8 or 15.6R when irradiated with gamma rays during hair development, and the corresponding value with scattering radiation was 4.29R. Lower doubling doses could be calculated based on published data from the stamen hairs of the same and three other Tradescantia clones irradiated more acutely. These low doubling doses seem to throw doubt on the safety standards of radiations."

And, the summary of SADAO ICHIKAWA's above article:
"Somatic mutation rates from blue to pink were studied in the stamen hairs of Tradescantia ohiensis KU 7 clone, a blue/pink heterozygote, exposed to 100 to 510 mR/hr gamma rays or to 12 mR/hr scattering radiation. The results obtained supported the previous finding of the sensitive genetic responses of this botanical system, demonstrating that the genetic effect could be detected with this system at a radiation level as low as 3.60 R total exposure (also possibly only 0.96 R) given at a low exposure rate
of 12 mR/hr. Pooling the present and previous data, a somatic mutation rate of 3.88 or 3.43 X 10 pink mutant events per hair per R was obtained for gamma-ray irradiation during hair development. The somatic mutation rate calculated for scattering radiation was even higher than this (1.25 x 10-s). The doubling dose of the somatic mutations at the specific locus was calculated to be 13.8 or 15.6 R when irradiated with gamma rays during hair development, and the corresponding value with scattering radiation was 4.29 R. Lower doubling doses could be calculated based on published
data from the stamen hairs of the same and three other Tradescantia clones irradiated more acutely. These low doubling doses seem to throw doubt on the safety standards of radiations."

Note: If you go to the above Wikpedia.org link and in the References section click on: "Ichikawa, Sadao (1972). "Somatic Mutation Rate in Tradescantia Stamen Hairs at Low Radiation Levels: Finding of Low Doubling Doses of Mutations". The Japanese Journal of Genetics 47 (6): 411–421." That link will enable you to get to Sadao Ichikawa's research article.

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Angusmerlin's final comments:
Turns out the the famous weed, the 'Wandering Jew' hails from the Tradescantia plant family. And, guess what? It's in my backyard. Every morning, now, I go out and check the color of my backyard's Wandering Jew stamens. Let me tell you, those little rascals are really tiny, and a wee bit difficult to see. Happily, so far, the stamens appear to be nice and blue. But, now that I have read Sadao Ichikawa's research article, I realize that I need to check more carefully, because it may be just one, or two stamens spaced between the regular blue that will turn to the irradiated mutated pink color in the presence of the radiation. Hum-m-m.

Well, for those of us, who cannot afford to buy a geiger counter, the Tradescantia plant family may present a cheaper, alternative geiger monitoring system.

Boy, I sure hope those little blue flower stamens don't turn pink!