Can Plants Think? The Torch Podcast

An Interview with Professor Catherine Kleier, Ph.D.

On this episode of The Torch, we examine the fascinating and unique world of plants—their genetics, habitats, evolution, and the future of plant science.

Here to discuss the “story” of plants is Catherine Kleier Ph.D., Professor of Biology at Regis University.

Image of baby plants growing in germination sequence on fertile soil with natural green background

The following transcript has been slightly edited for readability.

Can Plants Think and Sense — Like People?

The Great Courses: Thanks for joining us here.  This is an exciting course for us because it expands our content in this area. You have a lecture in the course called “Plants Are Like People.” I love that. How so? How are plants like people?

Catherine Kleier: There is a great book called Plants Are Like People from the ’70s and the book said well, what kind of water temperature does a plant like? Well, a plant likes the same temperature you would like. You like sun, plants like sun. So it was sort of a cute title.

It’s actually this new branch of study called Plant Intelligence. Really the idea is: are plants really able to think? Can they sense? What is that all about? I’ve sort of explored some of the latest findings from that branch of plant biology.

Learn More: Plants Are Like People

The Great Courses:  Can plants think?

Catherine Kleier: Well, they have evidence of responding to things. For example, in the lecture I talk about an experiment with the sensitive plant. This is a plant that will drop its leaves when you touch it.

Over time this particular scientists sort of trained the plant to not respond to her dropping it. How did that happen?  She had conditioned these plants by dropping them a lot so that they no longer drop their leaves anymore, but when they got a different stimulus, they’d still drop their leaves.

The Great Courses: Is that thinking?

Catherine Kleier: I don’t know. I’m not a cognitive scientist. I’m just here to tell you about the botany.

Similar Structures

The Great Courses: All right, let’s talk about botany. Do all plants have similar structures?

Catherine Kleier: Yes. Absolutely. Chloroplasts. Chloroplasts are tiny little organelles that live in the cell and that’s where the photosynthesis takes place. Except for parasitic plants. Let me tell you something about botany. There are no rules.

The Great Courses: There are no rules? Really?

Catherine Kleier: It’s really hard to have rules. Botany has what we fondly call physics envy. We’d love there to be laws, but there aren’t really.

The Great Courses: Or are there just exceptions to the laws.

Catherine Kleier: Always.

The Great Courses: There’s a lot of exceptions.

Catherine Kleier: Exactly.

The Great Courses: So back to my question about structure: roots, do all plants have roots? Do all plants have a stem? Do all plants have leaves? These are the common things that I know about plants. Talk about those elements.

Catherine Kleier: Exceptions to each one of those. There are certainly plants without roots, there are plants without stems, and oddly enough there are plants without leaves or at least plants that have modified leaves that don’t look like things we recognize as leaves, like cactus. Their leaves are actually the spines.

The Great Courses: Are there microscopic plants?

Catherine Kleier: There are. There are plants that are really small to the order of millimeters, but most plants are visible to the naked eye.

The Great Courses: Do we know how plants evolved?

Catherine Kleier: We have a pretty good idea. We don’t know how flowering plants began and then evolved to take over the world so quickly. That’s Darwin’s abominable mystery that I’ll talk about in the lecture about flower evolution.

Learn More: Secrets of Flower Power

The Great Courses: Why do you say they took over the world?

Catherine Kleier: Well, because in about 40 million years according to the fossil record there was a flower and then 40 million years later there’s flowers everywhere. Forty million years sounds like a long time to us, but really in geologic time it’s not that long.

Image of flowers on Carrizo Plain National Monument California USABotany vs. Gardening

The Great Courses: What makes you a botanist versus a gardener?

Catherine Kleier: I can’t tell you how much I love this question because oftentimes when I meet people and they’ll say, “What do you do?” “Oh, I’m a professor of Botany.” They’ll say, “Oh, you must have so many houseplants and have a great garden.”

The sad truth of the matter is I have a horrible garden. I don’t really have a garden at all and I’m not actually that great with houseplants. I do my best, but mostly it’s benign neglect. I like to describe botany as observing plants in their natural habitats. It’s sort of like the difference between a wildlife biologist and a pet owner.

I like to describe botany as observing plants in their natural habitats. Catherine Kleier Click To Tweet

The Great Courses: Right, and you are a field botanist, right? Explain what that is.

Catherine Kleier: I am a field botanist. That means that I like to go out in the field and literally observe plants in their habitat.

I’ll ask all kinds of questions? Where do they live? Who do they like to live with? How do they make a living both in a physiologic sense and a broader sense? How many are there? All these kinds of questions are interesting to me.

Genetically Modified Plants

The Great Courses: Talk about the controversy around genetically modified foods as something for us to consume. First of all describe what these genetically modified plants and foods are.

Catherine Kleier: Basically you’re just taking a gene from one organism and you’re inserting it into another organism. A very famous example is golden rice.

We took a gene from a daffodil which actually produces beta carotene. This is a vitamin that people need. Then this gene got inserted into rice, so now the rice makes that same vitamin. This is great because now you can eat rice instead of having to find the vegetables that have beta carotene.

On the bad side of this you’d have to eat a lot of rice to get the same amount of nutrients. Then it’s sort of questionable as to what other nutrition things might be lost and then some people are concerned about well, perhaps I could have some sort of allergy to something like that.

The Great Courses: Is that what the concerns are? Is that why people are freaked out? People are very freaked out about this.

Catherine Kleier: They are very freaked out. I guess allergies is one concern. Another concern is sort of super weeds that genetically modified organisms will take over, but I think a bigger concern amongst botanists is that we’ve genetically modified plants to make their own pesticides.

For example BT corn. We’ve genetically modified it so that it will produce a pesticide that prevents this beetle from eating it. The corn bore, actually it’s a lepidopteran. Not a beetle. In any case what happens is that over time the beetles get used to that pesticide and then they become resistant to it.

This is much like antibiotic resistance. Then the genetically modified plants don’t work anymore. Then what do we do? We’re back to the drawing board with these.

Like antibiotic resistance, genetically modified plant pesticides stop working. Then what? Click To Tweet

The Great Courses: Aren’t some plants already the results of gene splicing? Like cauliflower?

Catherine Kleier: Yes, well it’s artificial selection and so cauliflower and broccoli and brussel sprouts and kale are all the same species, brassica oleracea. We’ve just modified them over time to look like a Chihuahua or a Great Dane, et cetera. It’s sort of the same idea.

Learn More: Modifying the Genes of Plants

The Great Courses: Do you think that we will get over GMOs, will there be more GMOs? There are laws, countries are saying no to GMO products. What do you think is going to happen politically with some of that stuff?

Catherine Kleier: I don’t think so. I think that we’re going to see more and more of these organisms because there’s a new technology called Crisper Cas 9 where you can basically create your own mutant in your garage.

The equipment is just not that expensive and if you’re a hobbyist and you wanted to sort of knock out a gene in a particular organism, you can do that now. That’s how advanced that technology is.

This is genetically modified because you’re just knocking out particular genes and this is really great because then we can see what those genes actually do, how that change manifests in the organism, in the physical organism. It’s not actually taking a gene from one organism into another. I think we’re just going to see more and more of this.

Bee Pollen

The Great Courses: There’s been a lot of discussion lately about bees and the bee population dying down, its effects on pollination. Talk about that a little bit. Is that really a big concern?

Catherine Kleier: Oh yes. Colony collapse disorder is huge and I think at least the most recent evidence that I’ve seen is that their pesticides are a huge component of this particularly neonicotinoids.

Neonicotinoids aren’t nicotine exactly, but they’re somewhat like that in terms of a pesticide. These are thought in combination with other things, but the evidence is somewhat convincing that this is a big reason why some of the bees are collapsing.

The Great Courses: Talk about the affect of it. The collapse is happening so what is not happening to plants?

Image of Bee in Flight about to land on flower
Learn More: The Coevolution of Who Pollinates Whom

Catherine Kleier: Pollination. Bees do most of our pollination. If we had to go around and pollinate all these plants with a paintbrush, that’s really going to take a while. That’s really going to slow down your apples and cherries and almonds and all that kind of stuff.

The Great Courses: Is there anything we can do? What are we doing?

Catherine Kleier: Well, what’s interesting now is that we have a lot of beekeepers that actually travel around so they have the hives in the back of the truck and then they bring the hives to the farm.

The Great Courses: Bring the bees, like bees to go.

Catherine Kleier: That’s exactly right. These beekeepers, they have to tend their bees very carefully and basically this is going to raise the cost of food because the bees are a natural ecosystem service. Wild bees and bees that live in nature are doing this for free.

Global Warming

The Great Courses: Let’s talk about the other hot button issue related to global warming. How is global warming affecting the planetary plant life?

Catherine Kleier: Oh my gosh, so many different ways. I talk about that a lot in the course mainly because it’s really compelling evidence.

Regardless of how you feel about climate change, plants are doing something and they’re responding to something. I have a lot of pieces of evidence where plants are moving up in elevation, they’re colonizing further and further up mountains because the temperatures are getting warmer and so they’re able to exist higher up the mountain. That’s just one example.

The Great Courses: What happens when plants are going higher and higher? Is that bad?

Catherine Kleier: No. On the one hand, it’s funny, I’m an ecologist and I’m also an eternal optimist so I’m like yea, more plants! I think to myself wow, plants are going to be higher and higher in elevation and that means I get to climb higher and higher up the mountain, which is awesome.

In some ways it’s really interesting, but those changes might mean more habitat, but they also are not so great for animals that might run out of space. Some of these plants might actually run out of space. They might run right off the mountain so to speak.

The Great Courses: Let’s talk a little bit about the rain forest. Conserving the rain forest is a big deal too.  What is it about the diversity of the rain forest that’s so important?

Catherine Kleier: There are many different hypothesis as to why the rain forest are so diverse.  Regardless we do know that there are way more plants in tropics than there are in the temperate zones.

Part of the reason that this is important is because we don’t know what’s down there. We haven’t discovered half of the things and all of our medicines, or at least most of them come from plants.

Learn More: Why the Tropics Have So Many Plant Species

The Great Courses: What are some of the biggest discoveries in botany recently?

Catherine Kleier: Oh wow. Oh my gosh. I think one of the most exciting is this really cool discovery. It’s actually not exactly botany, but botany is very friendly.  So even though fungus and algae aren’t really in the plant kingdom we’ve sort of accept them.

The Great Courses: Yes, come on in. It’s a big tent.

Image of Yellow Lichen on Tree TrunkCatherine Kleier: Right. We can play in the sandbox together. A really important discovery recently has been lichen. Lichen were thought to be just a relationship between fungus and algae.

Now it’s been recently discovered that most lichens are actually two different species of fungus and another species of lichen. It’s actually a symbiotic relationship of three organisms.

The Great Courses: Why is that important?

Catherine Kleier: Well, because it used to be two for a really long time. People couldn’t grow lichens in labs. They’re like, “Why can’t I grow this lichen in the lab?” It turns out you’re missing a whole partner of the party!

Keep reading:
Will Flowering Plants Take Over the World?
Did Famous Genetic Scientist Gregor Mendel Fake His Data?
Birding in North America: The Torch Podcast

From the Lecture Series:Plant Science: An Introduction to Botany
Taught by Professor Catherine Kleier, Ph.D.