[Rockhounds] OT: Blazes of light reveal how plants signal danger long distances

[Axel Emmermann]

Hi Kreigh & list,

Technically, if there is no light emitted as a result of excitation by light of a shorter wavelength, we cannot call this fluorescence 😉
Since the emission is caused by living things, I would rather call it bioluminescence.
Nitpicking even deeper, one could postulate that the plant probably releases some hormone or enzyme upon being wounded. So the emission would border on chemiluminescence as well. Very comparable with the luciferase/luciferin  mechanism that make fireflies light up in the dark.
I wonder if the signal is picked up by nearby plants apart from the own system as well... 
The writer fails to make clear if the protein that luminesces around the calcium ions needs to be made visible by some external UV source or if it produces the emission independently. 
In the latter case it's bioluminescence. If UV is needed, it's fluorescence. 

Nitpickingly yours
Axel

-----Oorspronkelijk bericht-----
Van: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> Namens Kreigh Tomaszewski
Verzonden: vrijdag 14 september 2018 5:47
Aan: Rockhounds at drizzle.com: A mailing list for rock and gem collectors <rockhounds at rockhounds.drizzle.com>
Onderwerp: [Rockhounds] OT: Blazes of light reveal how plants signal danger long distances

In one video, you can see a hungry caterpillar, first working around a leaf's edges, approaching the base of the leaf and, with one last bite, severing it from the rest of the plant. Within seconds, a blaze of fluorescent light washes over the other leaves, a signal that they should prepare for future attacks by the caterpillar or its kin.

The biosphere and geosphere are intertwined by fluorescence.

Read more at:
https://phys.org/news/2018-09-blazes-reveal-danger-distances.html#jCp

Kreigh
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