Strange to be introducing a new project on my conclusion post, but it’s a cool one!
While waiting for pea plant project parts to arrive, I revisited another project that Monica Gagliano had done with the Mimosa pudica: https://youtu.be/Xm5i53eiMkU?t=2m45s. For those of you too impatient to watch a video (like me!) the Mimosa pudica is a plant that is
“known for its leaf-folding behaviour in response to physical disturbance.” Basically, its leaves fold up and/or its stem falls when it receives a strong enough stimulus:
(For excellent background reading on the Mimosa pudica, go here.) Basically, the new kid on the block is shy, sensitive, bashful. But with some training, could they become less so? Can they habituate to a certain stimulus?
“Habitu-they can!” is what Monica Gagliano et al. said in their paper, “Experience teaches plants to learn faster and forget slower in environments where it matters.” She dropped some 56 mimosas 60x in a row, 7x a day, to see if they’d stop closing their leaves after a while, when they ‘learned’ the stimulus wasn’t harmful. She measured leaves before and after as the measurement of response.
Sofie, a high school intern with us, built this plant dropping machine and ran some pilot tests:
Unfortunately, we got banned from the closet to drop the plants. Last weekend, I dropped 12 plants in my apartment, 9 in the experimental group and 3 in the control group. 60 times, 7 times a day. 3,783 is the number of times I would take a plant and drop it.
- Drop control plants once, 8 hours apart.
- Drop experimental plants 60x at time 0, after 10 minutes, after 1 hour, after 2 hours, after 4 hours, and after 6 hours.
- Then give them a new stimulus: in our case …
Yes. We shake the plant. The idea behind this is that the leaves will close right up again because it’s a new stimulus.
- Finally, drop it 60 more times after 10 minutes (once the leaves have opened up). Since it’s a familiar stimulus that they have hopefully learned is not dangerous, we’d expect plants to open up again.
But as always, we need to compare it to a control. Putting all the data together, here is what we find:
Want to see Monica Gagliano’s results to compare? Of course you do.
There are several important differences between my data and Monica Gagliano’s data.
- Her control plants closed a lot more in that first drop.
- She noticed learning during the first 60 drops, meaning the leaves started opening up in the middle of the 5-10 minute period when they were being dropped. My plant students, not so smart. They peaked learning at 2 hours and then seemed to forget most of it quite quickly. Hmm… not so much different from my human students…
- Her plants showed a strong response to the dis-habituation stimulus. They really didn’t like Swift’s suggestion to Shake It Off. My plants seemed to treat being shaken the same as being dropped. (Monica Gagliano’s protocol was to put them on a 250rpm shaker for 5 seconds. 250 rpm:
Her data is statistically significant. Mine? To be determined….
Qualitatively, what I noticed was that the plants seemed to exhibit maximum learning at 2 hours. They seemed to habituate to the force of stimulus rather than what the stimulus was (explanation for similar response to dishabituation). Also, notice how high plants 1-3 are in my graph post dis-habituation (upper right corner of my graph)? That’s because I only dropped them once, instead of 60 times, much like the control. I should probably take that out for my poster, but I wanted to show you all.
Anyway, if the plant’s brain is in its roots, as Darwin proposed, who knew that dropping plants on their heads would help them learn?
I’ll leave it here, but I’d like to thanks some people for helping me carry out my projects. Couldn’t have done without them:
And of course, all the people at the BYB office: Zorica, who would take extra care for the plants and go out of her way to help us; Katie, who would always make space for me crowding her space at the 3D printer; John, for lending out his beloved tools; Caitlin, for being patient with my late blog posts; Will, for his awesome mustache; Sanja, for help with getting me reimbursed; Greg, for being captain of this fellowship experience!
So much more to share, and I’m still waiting on one more data result, but goodbye for now!
But Why Plants?
Recording an Action Potential from a Sensitive Mimosa!
With the Introduction of the The Plant SpikerBox, you can, for the first time ever, explore plant behavior and electrophysiology at home or in the classroom. But wait…. Plants? Why are neuroscientists interested in… plants…?
What has a brain?
When we work with young students, we often begin by asking them “What has a brain?” You get your typical responses, like “I have a brain,” “my dog,” “my cat,” etc. Then we ask them to clarify, how are they defining that category, and often we hear the response “They move on their own!” This is true, and the mechanics behind movement in brained creatures is a fundamental element of neuroscience and electrophysiology. But, there are living creatures without neurons that move: Plants!
Certainly you’ve seen a plant growing towards the sun, opening up its leaves or petals during the day for better exposure or pollination, but what’s more, there are some plants which exhibit rapid movements in response to direct stimulation. We created the Plant SpikerBox to record the electrical activity of these plants! Like the Neuron or Muscle SpikerBox, the Plant SpikerBox is a kit which is designed to make electrophysiology preps easy, so that students and teachers can focus on the science and experiments and not be bogged down by technical issues.
Disclaimer: Venus Flytraps do not have subterranean brains.
We proved this to be an idea worth spreading… Our 2017 TED Talk (Vancouver, BC) introduces viewers to this little-known world of plant electrophysiology. On the TED main stage, our CEO Greg Gage explains the principal elements of electrophysiology research, demonstrating that the electrical signals which control our own bodies are also present in plants! He proves this through a number of demonstrations, first by visualizing his heartbeat with our Heart and Brain SpikerShield, before moving onto the plants.
You can see the TED talk here!
To return specifically to the Plant SpikerBox, we encourage users to first find a Venus Flytrap, the plant that Darwin called “One of the most delightful plants in the world,” and investigate its eating behavior…
In order to supplement its nutrition, Venus Flytraps capture and “eat” insects. In order to do so, they have to snap their traps shut quickly so their prey doesn’t escape. But how does the plant know when to snap its trap shut and how do the mechanics of this action work?
Stimulating a Trigger Hair in a Venus Flytrap
Just like humans and animals, Venus Flytraps use electrical activity to move! Recording this signal with the Plant SpikerBox reveals that, like us, plants use “Action Potentials” to send movement signals! In the TED talk, Greg demonstrates how Venus Flytraps distinguish between false alarms and real prey. These are the amazing plants which inspired our interest in plant electrophysiology, we hope you find them as incredible as we do! Check out this experimental write-up to learn more!
Anatomy of a Sensitive Mimosa and its Behaviors
Another interesting, rapidly moving plant is the Sensitive Mimosa, or Mimosa Pudica. Also known as the “shy,” or “bashful” plant, the Sensitive Mimosa will fold up its leaves and branches when it is touched or flicked. Using the Plant SpikerBox, you can experiment with the Sensitive Mimosa and discover how Action Potentials are responsible, again, for the dramatic movement response when you flick the stem of the plant. On the TED stage, Greg demonstrates these two kinds of behaviors, showing how the leaves fold up with soft touches, but entire branches fold when flicked. See the experiment here!
The Sensitive Mimosa has also received some attention lately following the announcement of the 2017 Novel Prizes! This year’s prize for Physiology or Medicine went to researchers who study circadian rhythms, or sleep cycles, which were originally discovered in the Sensitive Mimosa! For a great explanation, check out the Nobel Prize website!
But perhaps the most exciting experiment you can perform with your Plant SpikerBox is the Interspecies Plant-Plant-Communicator experiment. To demonstrate the ubiquitous nature of the action potential, Greg uses the Plant SpikerBox on the TED stage to capture a signal from a Venus Flytrap and send it into a Sensitive Mimosa…
Screencapture taken just a moment before Interspecies Plant-Plant-Communication is achieved…
The Plant SpikerBox and Plant Sciences have a lot of potentials (ha!). There are countless other experiments to be performed on these plants alone, but investigating other plants opens a world of opportunities. Perhaps the Trigger Plant or the Telegraph Plant are hiding electrical signals? Perform your own experiments! Let us know what you discover!
The Plant SpikerBox is available in our store, and the companion recording software, SpikeRecorder, is free to download.
What will you discover?
On April 24, the co-founder of Backyard Brains, Greg Gage, returned to the TED stage to give another intriguing talk that included live scientific experiments: this time, he showed that plants, like animals, can use electrical signals to make rapid movements.
If you missed it, you can see the TED talk here!
Now, take a peek backstage where we interviewed Greg on the whole TED experience:
What was the most difficult part of doing an experiment with plants live on the stage?
GG: Two things. 1) Testing with Plants. The TED talk was in early spring, and we needed to test everything in the winter months on summer plants that do not bloom until after TED. So we got to work building a greenhouse in the office and our local Downtown Home and Garden (who housed four of our plants in their greenhouse! Thanks!), growing seedlings to mature plants so we could test our ideas within a few weeks. 2) Time pressure.We have only done experiments in lab settings and a few times in long talks/conferences when time wasn’t an issue. The TED stage is live and limited on minutes… not only to get the idea across but to do live experiments. We had a lot of unknowns to tackle before we agreed to the talk. 54 questions to be exact. Can we do quick recordings and switch across different plants? How do we move the plants to the stage without disturbing them? What are temperatures ranges in the theatre, and will the plants be responsive given those ranges? Can we bring our plants through customs in another country? Not to mention the Plant to Plant Interface which wasn’t invented yet!
How does it compare to doing experiments in a school classroom?
GG: In the classroom you have time to make mistakes and use them as learning experiences with the students. The TED clock is less forgiving. We had 5 live experiments to do in 7 minutes. We methodically removed the chance of failure by testing in the lab until we were 90% certain that they would work.
You developed a Plant-to-Plant Communicator. How does it work, and how did you come up with this idea? What was your inspiration?
GG: This was a fun idea playing on the idea of the ubiquitousness of spikes. Our human-to-human interface showed a similar idea with EMG activity. We first thought of a venus flytrap to flytrap interface. But then thought it would be more visual to get the mimosas to move. But would they move on stimulation? Our labs in Chile, Brazil and Michigan all pitched into the investigation. It turns out it worked… and worked beautifully.
What literature was involved in preparing the talk and experiment?
GG: We read every scientific paper we could find on the Venus flytrap and Mimosa Pudica (Of which there are surpisingly few).Electricity was known to occur inside the Venus Flytrap as early as 1873, but the action potential wasn’t reported until 1950 (Stuhlman & Darden, Science), and it wasn’t until 1961 that it was known that it took two action potentials to close the trap (also a Science paper). I enjoyed reading the early experiments by Charles Darwin especially. I wasn’t aware how much he turned to plants later in his career. He wrote an entire book on plants that eat insects!
Why did you choose to specifically talk about plant electrophysiology? What does it represent for science education?
GG: Exotic plants are exciting to talk about no matter what, but the fact that they have these silent secret messages passed through electricity was too much to pass up. Through plants, we can learn a lot about our own neurons…and do so in an engaging way, which is important for science education.
Do plants have brains?
GG: Ha! No, they do not, sadly. I wish. But they do have cells that share properties with our neurons,.
Why did you specifically choose Mimosas (Mimosa pudica) and Venus FlyTraps (Dionaea muscipula)
GG: These are fast moving plants. So you can see an obvious behavior in the plant that corresponds with the action potential generation. It’s not known actually if all plants use electricity, but it is thought so. It’s just not as easy to show convincing electrophysiology in live demos in more slowly moving plants.
What are your thoughts on the inner clock of the venus flytrap?
GG: There are a few theories out there, but the evidence hasn’t fully satisfied any of them… so I think the jury is still out. We have formed our own theories about how it works from our daily recordings the past few months… but I want to be sure to run more controls and experiments before we say what that is.
Tell us about your preparation for the talk. What was it like?
GG: 90% of the prep was on the hardware, software, configuration of the electrodes, and figuring out international plant law (we are now experts in the latter). I didn’t start piecing the talk together until once we knew what parts we had to work with. Remember, we were only confident of 2 of the 5 experiments when we found out we were going to speak. But I love that period of true focus and creativity. It’s such a pleasure to be able to tackle a large problem and figure it out. We had a great team of people that made it possible.
What was the best part of TED 2017?
GG: The people you meet. Everyone that attends is intellectually curious and wants to know more about a lot of subjects. And there are a lot of experts there. I had late night talks with the hardware developer of Google Home about microphone theory, then another about laws that are being passed through Congress to protect phone privacy as immigrants and visitors come through customs.
What was your favorite talk? Why?
GG: I had two. The poet David Whyte and the group OK Go gave two talks that spoke to the creative process in very different ways. David broke down how he derived a few of his poems in beautiful detail through conversations with his daughter. It was interesting (and honest) to hear the story, the thoughts, then the poem. OK Go explained a different approach, something that speaks to me about Backyard Brains. Their approach to making their amazing videos was to play in a creative sandbox and see what works, then make the project about what works best. Less pre-planning, / pre-staging and more just playing/prototyping while doing it. That’s what we did on the plant talk. We knew the talk was about plant electrophysiology. We had the raw materials: plants and amplifiers, and we had to come up with something creative within that space.
Are there any peculiarities regarding doing live experiments on plants that surprised you? As plant electrophysiology is a bit more temperamental than vertebrate electrophysiology.
GG: I was surprised at how reliable we were able to make these famously fickle plants. From all of the variables we tested for the mimosas: temperature, humidity, light, time of day… we found out that the only real thing that mattered was a good light source and that the plant was “awake” in the day. We tested in the office with air conditioning on for days at 61 ºF (16 ºC), pushing a little on the chilly side for the plant, but mimicking possibly cold theatre conditions, and it didn’t matter. The mimosas were still responsive. The flytraps had to be healthy, but little else mattered as well.
Hardware: The Plant SpikerBox
The Plant SpikerBox is the tool we created to allow students, teachers, and excited amateur scientists to perform these experiments at home or in the classroom. This one kit allows you to perform the Venus Flytrap experiment, the Sensitive Mimosa experiment, and the Interspecies Plant-Plant-Communicator experiment. Check the experiments out and see the Plant SpikerBox in the store for more details!