Are there any naturally fluorescent plants?

What taxonomic background I have is mostly in zoology, and I could probably name a dozen different animal groups that have been shown to naturally fluoresce without thinking too hard. All I can find about fluorescent plants are cases where people have genetically engineered plants to make fluorescent proteins. There are of course fluorescent as well as bioluminescent fungi. Are there any naturally fluorescent plants? Thank you.

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chlorophyll fluoresces red under UV light. so i would think most plants are fluorescent to some degree.

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Other than induced fluorescence I don’t know of any examples of naturally fluorescing plants.

Fungi, on the other hand, have a number of species that naturally glow. Of course, those aren’t plants, but at least they’re not animals.

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You mean like this one?
https://www.inaturalist.org/taxa/168594-Schistostega-pennata/browse_photos

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That’s not really fluorescing though, is it? As I understand it, it’s reflecting light in a way that gives the illusion of glowing, but it’s not actually emitting any light.

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If you consider algae to be plants, there are some that are bioluminescent.

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Do you mean bioluminescence (glow in the dark) maybe instead of fluorescence (emit a different color when exposed to a certain wavelength of light)? I think all plants fluoresce - chlorophyll was already mentioned as a fluorescent molecule, and there are many phenolics and secondary metabolites in plants that fluoresce as well. I think pretty much everyone who has ever done fluorescence microscopy on plant samples knows about the issues with background noise that can be caused by this autofluorescence when trying to observe a genetically introduced molecule such as green or red fluorescent proteins.

However, when it comes to bioluminescence such as the glow of a firefly or the light emitted by some deep sea creatures, I am not aware of any plants that can do that unless genetically engineered by introducing the luciferin gene and provided with the appropriate substrate. The only “plant-like” organisms that I can think of that do that are some algae, specifically dinoflagellates, which aren’t even in the kingdom Plantae. They make ocean water glow in the dark when swirled up.

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Interesting. I knew that once long ago and had forgotten. Thank you.

This raises the question, when I go out at night with a UV light looking at fluorescent animals, why can I not see any red fluorescence from the plants?

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I’m interested in fluorescence rather than biolumenescence, and Plantae rather than algae, but you remind me I have seen fluorescent encrusting algae.

I often carry a UV flashlight with me when I’m out at night, and have happened upon a variety of fluorescing animals that I didn’t expect to fluoresce (geometrid caterpillars, for example). I haven’t come upon any apparently fluorescing plants. Do you happen to know, is this because I’m using the wrong excitation wavelength, I’m in the wrong region (California), or the fluorescence is too dim?

Some flowers fluoresce under Uv light, and some insects see such wavelengths more easily than we do. Look at a california poppy with a uv light (in the dark) to see how it looks to an insect pollinator.

As @pisum says above, chlorophyll fluoresces. Here’s a fun expediment I used to have kids do at after school science club.

Chlorophyll Experiment (2nd grade and up)

Chlorophyll turns bright red under UV light. Wearing goggles for safety, Kids will extract chlorophyll from spinach or other dark green leaves and examine the extract under UV light in a darkened room or closet.

Materials:
o Leaves for chlorophyll extraction
o isopropyl Alcohol (use with crushed leaves to extract chlorophyll
o Mortar and pestles to crush leaves into a mash*
o Filtration setups, jars/test tubes, coffee filters

Steps

  1. Write kid’s names on jars using Sharpies
  2. Use mortar and pestle to crush leaves – about ¼ cup
  3. Stir in a tablespoon or two of rubbing alcohol
  4. Place coffee filter into baby food jar so it forms a cone (roughly)
  5. Scrape leaf/alcohol mixture into a coffee filter
  6. Squeeze the coffee filter gently, allowing liquid to drip into jar or test tube
  7. Cap the jar or test tube
  8. Examine the chlorophyll extract under UV lighting in a dark room.

*if I had a time constraint, instead of using a mortar and pestle, I had the kids take turns mixing leaves and alcohol in a magic bullet or other blender.

chlorophyll fluorescence is not as strong as fluorescence from sources like manmade materials (which often shine very brightly under UV). so most likely, your light source is putting off enough light in the visible spectrum that the reflected visible light is overwhelming the fluoresced red light. this is especially true if you’re using an unfiltered 395nm UV light, since the noticeable purple glow from these lights can easily overwhelm the red from chlorophyll.

i mostly use a filtered 365nm UV light for looking for fluorescence in nature. it produces only a faint light blue visible light, but even that little bit of visible light, especially if reflected back (or possibly fluoresced back as blue?) by waxy or cellulose-y (lignin-y?) surfaces can hide the red from chlorophyll. so things like mosses, ferns, and legume leaves are probably going to give you a more noticeable red than things like grasses and magnolia leaves.

it’s also worth noting that the chlorophyll fluorescence will fade in intensity over time, though this property allows you to do something like a sun print, which can be fun.

just for reference, in my area, the only natural thing that i’ve discovered that fluoresces with intensity on par with manmade materials are some millipedes (especially their legs), which fluoresce a bright bluish green. lichens are a distant second in terms of intensity, though they probably have the largest diversity of colors – yellows, oranges, blues, greens, and even reds. next in intensity are some of the fleshy caramel-colored mushrooms in my area that fluoresce green, and this is on par in intensity as the red from chlorophyll. there are other things that fluoresce, but they tend to be less common or tend to be relatively small structures / relatively inconspicuous.

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The best wavelength for chlorophyll fluorescence is around 400 nm just at the boundary between UVA and violet/blue visible light. I think most UV/black lights are around 395 nm, so they should work. Fluorescence will be around 700 nm at the border to far-red and just barely visible to the human eye. Fluorescence microscopes have no problem picking it up, but the human eye may be challenged, especially if the environment is not dark enough.

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You don’t? I do see it from plants when I’m using my UV light. It’s not strong, but I do see it.

EDIT:

Last night I took one of my UV flashlights out and one my cameras. This is a comparison between a non-UV image (taken this morning) and a UV photo taken last night. The camera is a Sony a6500 with a 70mm Sigma Art lens. Had to push the ISO way up to get an image and the camera has trouble focusing with the UV light. I rotated the normal image to more-or-less line it up with the UV shot.

The UV light is a Jaxman U1n 365nm, which it looks like may have now been rebranded the U1c.

From poking around at things last night it looks like young leaves show more red than older leaves, and plants with thin protective membranes also show brighter than ones with thick memberanse. Mosses and algae are especially bright.

Also, a small spider. Had a lo of trouble getting it in focus, so it’s a bit off. This fellow is on a different plant with thicker, more waxy leaves and they don’t fluoresce nearly as strongly as the more delicate leaves on the false heather.

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:) let us not forget scorpions!:scorpion: They are amazing under UV light! And, the chemical that causes the fluorescence is very durable - even scorpion fossils may fluoresce.

Discussion
https://www.sciencedirect.com/science/article/abs/pii/S0003347211005069

Imagery:
https://duckduckgo.com/?q=scorpion+fluorescence&t=ipad&iax=images&ia=images

Almost any cuticle type material (fingernails, snake sheds, some exoskeletons, some shells) fluoresce noticeably, as do teeth, in very dim lighting under a black light.

If you get a black light, be aware that different wavelengths are not safe for human eyes. I used to know the wavelength range of safer UV lights, but I’ve forgotten.

This thread made me place an order for a UV flashlight. Curious what kind of glowing stuff I will find in my backyard :sunglasses:

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I think I read that birds see different wave lengths that us humans. I am almost sure that hummingbirds see flowers differently that us.

I expect you’re are right about bird’s vision. Here are interesting examples of what some flowers look like to us compared with how they look to a bee or bird.

https://duckduckgo.com/?q=flowers+under+uv+light+what+do+bee+see&t=ipad&iax=images&ia=images

I like this picture comparing human to bird vision, though it does not mention uv light.

https://www.pinterest.com/pin/572801646347465682/

Good job keeping it rated G :grin: