Nature has always served as Mankind’s early warning system — the canary in the coal mine, and possibly, the spiderwort in the nuclear plower plant. You may not think of garden plants as particularly active, but many have unique “behaviors” that are somewhat entertaining, and at times even useful. The ephemeral blooms of Tradescantia, also known as spiderwort, among other fun names, have special sensitivities: the tri-petal flowers open and close based on the weather and light levels; when it is really hot, the flowers close, but on an overcast or rainy day, they seem to glow. But the most exciting Tradescantia trick is that it will change flower colors when exposed to low levels of radiation, among other pollutants. It is fairly easy to find bloggers exclaiming the virtues of Tradescantia in detecting radiation (some groups even guerilla plant Tradescantia around nuclear power plants). They claim that Tradescantia flowers generally turn from blue to pink when exposed to low levels of radiation. This claim is both over- and under-inclusive. First, there are about 70 Tradescantia species native to North America, with flowers in several, naturally-occurring colors: blue, purple, white, pink, magenta, white with purple stripes, and even more varieties native to other parts of the world. Some are just natually pink. But it is true: scientists have discovered that cells of the tiny hairs on the stamen of the Tradescantia ohiensis KU 7 clone turn from blue to pink when exposed to various forms of radiation in the laboratory, and other scientists have found that other species of Tradescantia display this chameleon trait in the wild too.
I have seen a clump of flowers on my own Tradescantia hybrid suddenly turn from purple to pink, even while others on the same plant remained purple. Curious. However, this “warning system” is of limited practical use. It turns out that the flower is sensitive to many common pollutants, like car exhaust and cigarette smoke too. So seeing my blue spiderwort turn pink means … the city air is polluted; which is about as useful as seeing through the sweat dripping from your brow that the spiderwort has closed it petals to tell you it is hot outside. Nonetheless, the plant’s ability to detect radiation will no doubt be of some use in the lab and perhaps one day in the field. It is one more area where Nature’s genius can provide answers for Mankind.
Note: Tradescantia is another one of those plants with fun common names, like spiderwort and snotweed; but given it’s usefulness to science, I think it deserves a more respectful moniker than “snotweed.”