Albinism in plants
The other day, while chasing birdies for the Forest Service, I encountered a pretty wildflower along an abandoned logging road. The plant was small purple-fringed orchid, Platanthera psycodes. It was unusual in that the flowers were white rather than the normal lavender to reddish-purple one generally encounters.
I posted a picture on my Facebook noting that it was a “light specimen.” My friend and botanist Pat Cox commented that it looked like “an albino form.” For some reason, I had never thought about white flowers being albino, but it makes sense.
First to clarify a little — in this instance it is the flower that is albino, not the plant. You can easily see the green stem and leaves. It’s easy to see how albino plants would have a tough time of it, because it would mean they had no chlorophyll and without chlorophyll there is no nutrient production (photosynthesis) in plants. But, believe it or not there are some albino plants.
One of the better-known instances is a group of albino redwoods out in California found in Henry Cowell Redwoods State Park and Humbolt Redwoods State Park; these albinos are totally without pigment, all the foliage is white. They survive because they are sprouted from the rootstock of normal parents.
It got dizzying after a while trying to sort through all the genetics involved in albino or albiflora flowers, but albinism is generally a mutation that occurs in the chemical pathway that creates the color pigments. It is a recessive trait — remember that from genetics, dominant and/or recessive? So in order to get an albiflora form the plant must have a pair of recessive genes (a/a) because two dominant genes (A/A) would, of course produce the dominant color and even (A/a) produces the dominant color because the A is, well, dominant.
Now, in nature, plants can be self-pollinated, cross-pollinated or either/both. Albiflora plants that are self-pollinating would continue to produce albiflora forms – they would continue to pass on the a/a traits. The occurrence of albiflora forms in cross-pollinating species seems to depend on the luck of the draw up and until the time when albino flowers become common enough that insects would likely encounter different albinos in their daily foraging. But current research seems to point to another difficulty in cross-pollination of albiflora forms — the fact that insects seem to eschew white or albino flowers when normally pigmented flowers are available.
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Many “white” wildflowers are actually a pale representation of the dominant color. I’m not sure exactly how the color gets watered down because obviously recessive genes are present but not dominant. Then there is nutrition and soil type and many other factors. I think many people are aware that increasing acidity of the soil will turn your cultivated hydrangeas bluer in color. Then there are flowers like water lilies that get their whiteness from the structural makeup of the flower. The cell structure of some flowers creates the white color by reflecting the entire color prism. I believe water lily is an example of this.
After communicating a little with Pat, I feel the orchid I saw was indeed and albino, basically because of the pure white of the flowers and no hints or tinges of color were seen anywhere.
(Don Hendershot is a writer and naturalist. He can be reached a This email address is being protected from spambots. You need JavaScript enabled to view it..)
