Stacey Smith on Flower Color Evolution and Life as a Botanist

Transcript:

The other big surprise was that I would have never guessed this, but plants combine different pigments to make red. And the color rules don't follow what you would think, right? So for us when we're painting red is a primary color, right? You don't make red by mixing colors, you mix colors like you mix red and yellow to make orange, etc. Plants, I don't know how this works, but they mix orange crotenoids like the chemicals that are in carrots that make carrots orange with purple anthocyanins, that things that make, let's see, like blueberries blue, but if you look at them, they're actually kind of purple in solution. You combine the purple and the orange yellow pigments and it comes out red. Hi, welcome to the Science Fair podcast. I'm your host, Susan Keatley. I'm a PhD chemist, writer, and I love talking to scientists. On the Science Fair podcast, I aim to bring you conversations with scientists doing fascinating, cutting-edge work on all kinds of interesting phenomena, ranging from physics to chemistry to biology, and even the nature of science itself. Tune in every Monday for a new episode. For each scientist we interview, first we'll release a mini-episode that connects what the scientist is doing with what's happening in the high school science classroom, and then the following week the Villeinth interview. So come along. And tune in for some Science Fair. Our guest today is Stacey Smith. Stacey is an associate professor in the ecology and evolutionary biology department at the University of Colorado in Boulder. Her lab studies the evolution and genetics of flowers with a focus on the tomato family. Recent work in her lab has focused on the evolution of flower color. As this trait has a relatively simple genetic basis and is ecologically important. And results of the lab's studies suggest that flower color changes can involve a range of genetic mechanisms and often are driven by competition for pollinators. Today, Stacey is going to talk to us about her path as a scientist, her research, and how it relates to what some of you may be learning in your high school and early college science classes. Stacey, welcome to the Science Fair podcast. Hi, Sue. Can you tell us about your path to becoming a scientist, mentioning some of the pivotal moments that led you to becoming a professor at UC Boulder? Thank you, Sue, for inviting me. This is really fun. There were just so many little things. I don't think that a five-year-old starts out and says, "I want to be a university professor." Because that sounds really boring, right? Kids really like I want to be a firefighter or something that sounds really exciting. I really just loved plants from when I was a little kid. I just was always like, "What's that that's growing in? Can I eat it?" I was just interested in them. I wanted to garden, and I was just really lucky that people were super supportive in my life. You know, my grandfather would get me wildflower books. Another grandfather would send me birthday money, and I would always use it to go buy something interesting to grow. And it mostly didn't work out, but my parents let me roll with it. So, like, I planted an apricot tree and our beagle ate it. I was very upset about that when I'm sort of scarred by the apricot tree situation. I still want an apricot tree, but, you know, my parents have never been interested in plants, but I always was. And I went to college and just said, "What major is for people that like wild flowers? Like, what's the wildflower major?" And they're like, "That's not a major. Biology is the closest." And I was like, "Oh, definitely not. No, no, no. I took that in school. That was terrible." They eventually did convince me that biology is, in fact, the correct major. You know, I just kept looking for opportunities to do things that I found interesting and kind of getting over missteps. You know, trying this kind of biology and then realizing, "Well, I liked it in concept. It wasn't for me in practice." You know, like, ecology sounded right. It sounded so holistic. And then I was like, "This is too holistic for me. I need to get a little bit more understanding of a particular system. I need to dig in, literally." I explored a bunch of fields and eventually found that I can study wild flowers as a career. And lots of people do. And they're called botanists. Once I kind of realized that was my field, I get to wander around and keep doing different versions of botany. Chemistry versions of botany, genetic versions of botany, history versions of botany, all the versions. I like all the botany. What was your PhD in? Systematic botany. So there are not many botany departments left. So I just went to like, "Oh, here's a school where I could do research. That seems good." I sort of kept refining my interests and then by the time I was ready to do a PhD, I was like, "I need to go to a botany school, like a botany place." University of Wisconsin-Madison was one of the only ones that there was in the country and now maybe the only one. And it's going away soon too. So I was lucky to be able to go there to time when botany was big and botany should be big everywhere. One area your lab focuses on is flower color. We are going to open up with a question from a listener, which gets at the heart of why we even see flowers as colorful. This question comes from Megan, age 16, and a senior in high school in Boulder, Colorado. She asks, "In physics and in chemistry, students learn about the light spectrum." The question is, how do plant pigments, such as chlorophyll, anthocyanins, and carotenoids work with the visible light spectrum, to absorb certain wavelengths of light and then appear a certain color? We're not starting off with a light question here. I feel like I'm like, "This is triple jeopardy." This is what I find with teaching, which is why teaching is a good part of the job. Students always ask really hard questions. And this certainly is at the boundary of my knowledge and why maybe should have paid more attention in high school physics. But it all comes down to atoms and their electrons that are in their jiggling and can have different energy levels. And so electrons bounce between energy levels by absorbing energy. And how much energy it takes to move between the level depends on what kind of atom it is. And then of course, all of these pigments, the things that give plants color, the things that give us, you know, that make our skin whatever color it is, all of those are bunch of different atoms mixed together. And so the color that it appears depends on what kinds of light energy can be absorbed across the spectrum. And so it's going to be unique for every single chemical compound because each chemical compound has a unique composition of atoms in it. And so, Claire Phil, for example, looks green because it's absorbing the other colors of light, the high energy colors of light, and turning those into sugars for us to eat. And then it does not absorb green and that's how it looks to us. So, yeah, so all the visible pigments are doing this, but I think it's amazing. And that's why we have such a wide range of colors because all the combinatorics in there. And then of course we have amazing instances of convergence, like you can make purple with so many pigments. So, but it's completely chemically different, but appears the same to us in our eye. I didn't know that. Is purple unique in that way? No, purple is not unique. It just comes to mind because it's one of these weird examples where plants and fungi both learn how to make purple. So, you know, there's like purple mushrooms and purple plants and they do it with the same class of compounds, but not the exact same ones. And I think I think fungi actually have some other like they have lots of fancy ways to make color that are totally different from plant colors. Like there's no teal, you know, or fluorescent plants, but there are mushrooms that do all kinds of weird. I shouldn't talk mushrooms. I don't know mushrooms, but mushrooms are crazy. Why is flower color simple genetically traits that are simple are complex. It's kind of a people use these terms. And I think it's simple in the sense that you can find variation just by looking around. So, if you go to a field full of wildflowers, you're going to see ones that are darker or lighter. Some of that is just how well it was watered, how much sunsine it's getting, et cetera. And some of that is what's in its genes. And so, if you can have a couple plants that are in the same population and one is white and one is purple, and that difference is quote-unquote segregating in the population, there are different genes that are making those different colors, then it must be pretty simple. So, that's one of the reasons that Mendel studied flower color is one of his traits because it was something that just appeared naturally. And it does turn out people have studied it and found the genes that were broken to make a white pea. So, it's a broken gene and you get a white pea. So, it was kind of an in-road. And I think the other reason that it appealed to people is they say this is a natural reporter gene system that when it's a visible phenotypic change, you do something to the gene and you can see what it is. You can see what happens. You can see like, I broke this gene and now my flower is white or my flower is purple. So, I know that this genetic change has to do with that color change. So, it's been super important for just understanding how do genes make particular phenotypes, particular observable characteristics of our body? organisms. And so I'm interested in it for ecological and evolutionary reasons, but it's also accessible. There's all of this literature because for years people are like, hey, flower color is different. I bet there's a genetic difference. Yeah, there is. And sometimes just one gene. That's fine. That's easy. Sometimes it's not. Is this similar with like fur color of animals? Or is that a totally different thing? It's similar to a degree. Yes. So just generally, pigmentation is one of the most widely studied traits across organisms for just a basic understanding of genes and how they work. Because of this being a natural reporter system, you don't have to put, you know, Luciferase in there to make it glow to see if you made a genetic change. It's just visible. And many of those color changes and things are simple genetic changes. So they're just not always. There's always that like asterisk. They're not always simple, but like in flies and fish, we know so much about the genetic basis of color. My spurts. Why is flower color important? Ecologically flowers are an advertisement flowers appear when the plant is ready to make babies. It needs pollen typically to be moved onto the stigma to make seeds. Sorry, it gets a little botanical fast. But for all the plants that rely on animals, they need a way to say to the animal, come over here. Could you put your butt in that spot actually because that would really get the pollen onto the stigma grate. So plants need a way to talk to pollinators. And so flower color and the patterning that you can create with flower color is how plants talk to pollinators. So I was initially interested in that. It's very sparkly, of course. We can see all this flower color variation and you get very curious. The funny thing about this though is, as people have studied flower color more and more, we've realized that even though it may be often genetically simple, it's rarely ecologically simple. So you can imagine that some flower colors would work in some environments and not in others. Like red flowers. Wow. So easy to see in the desert. But if it's an addark forest, maybe not so easy to see. You may just want to have a white flower. So that something sees you. There's a lot of environmental effects. And then the other thing is we were talking about light absorbing and reflecting these pigments also are plant sunscreens. Plants don't get to go sit in the shade on a hot day. They are the shade. Plants are constantly having to deal with light energy and not overheat. They've got proteins in their cells. They can't do their job if they get too hot. What is blocking all of that heat? Pigments. Pigments are blocking all of that heat. They are allowing the cell to knock it too hot to work. Because otherwise the flower would just wilt, right? Flowers in particular need lots of pigments because if they're going to be visible, they're way out of the edge of the plant. Or they're sticking up out of the field. It's way at the top. Flowers are super exposed. And we're finding out that the selection on flower color from all of these environmental sources, maybe a bigger drug. Maybe a bigger driver than the pollinators in terms of how much pigment and what kind of pigment. Because the number one thing is plants have to stay alive. Those flowers have to be able to stand the cold and the heat. And pigments are totally key there. And so pigments first started. It's just sunscreen. Oh gosh, I'm coming on to land. And it's really sunny. And I need to cover up a little bit. Secondarily, there was the, oh, this is good for signaling. We can talk to pollinators this way. That's the story of evolution is constant co-option and building onto what's already there. Once they became involved in signaling, that's when pigments really diversified. And we got lots of different colors and lots of different pigments. Because being a sunscreen, you don't need that many different things to capture the different kinds of light. You can cover it with a handful of sunscreens. It seems like the colors really exploded when all of a sudden they were needing to do so many different jobs. But fundamentally sunscreen. It makes me think of, you know, like a group of children with like all the same color rash guard. You know, and then. So they're all protected from the sun, but how do they differentiate themselves? Well, now we'll get different colors and patterns and all these things. That's right. And your parent can be like, that's you over there. That's my kid. Right. Grab the one at the red shirt. If we could just kind of like go back many, many, many years in time, what, what would a landscape of flower colors look like in the very beginning when flowers first came on the scene? That is such an interesting question and people have tried to infer it. I think it's super contentious. I've actually been reading a bunch of papers around this lately. Because it's pretty clear that very quickly after coming on land, organisms evolved red pigments, what are visibly red to us, lots of different kinds of like mosses have red pigments liver were to all these little plants that represent the big branches of the plant tree of life. All of the they'll have these red pigments. So it seems like for sunscreens, you need to deal with the UV and then you need to have the red pigment as well. So you absorb what the chlorophyll isn't absorbing, right. The chlorophyll is getting its wavelengths to do photosynthesis and the red is like, I'll handle the rest. I'll keep you from getting too hot. So red pigment was certainly available to make flower colors, but not all animals see red as a good contrast with green. So we think that probably the first flowers were white. They were probably just a good contrast and they worked in lots of light environments. And then as animals diversified and they could see lots of different colors and it's unclear how simultaneous this was right. Are we getting all these different kinds of butterflies and their vision, their vision systems are expanding and diversifying and so plant colors diversifying and the same for hummingbirds or any other pollinating animal. That timeline is really tough because for butterflies, for example, we have no fossil record hardly. And then on the other animals like vertebrate animals, pretty good, pretty good fossil record, but plants, we are still working on it. So the understanding who was being colorful first, who was seeing color first, who was using color for singling first. That's a really hard one, but we're working hard on the plant fossils, even in my lab, I've learned like, okay, well, somebody's got to go look at these fossils. Somebody's got to go start figuring this out like nobody's going to do it if it's not you, which is always the story and science, right. Eventually you realize like if it needs to be known and I think I'm the one who think this needs to be known, I need to go work on it. Where do you start in terms of trying to find plant fossils? There are paleo botanical sites around the world where people have been accumulating material like where there was lakes and there was compression and tons of plant fossils. So actually there are collections all around the world that are full of plant fossils stuffed with fossil pollen and seeds and leaves and cones and just all kinds of stuff. The problem is there are just so few people who take the time to go look. And so a few years ago, actually more like 10 years ago, my lab was like we need more tomato family fossils because we work on the tomato family. We don't know how old it is. And so we applied for money from the government to go around the world and dig through all of these collections and the scientists who I worked with she went to Russia. She went to Germany. She went to the Netherlands. She went all over the place and looked for these fossils and the wildest thing was one of the most interesting fossils she found right here in Colorado, a chili pepper fossil. She was over at the museum and she WhatsApped me the picture of the fossil. And I said, is that a Lissie and these which is in the chili pepper clay and then where are you and she was down the street at the museum and here's this 50 million year old chili pepper fruit fossil down the street. We had been we went to frickin Russia to look for this and it's in Colorado. This was shocking to me and it was a good reminder that you don't maybe have to work that hard to find the fossils. They're around. It's just the right pair of eyes. So like we know what the characteristics are that we know what an ancestral you know chili pepper might look like. I wouldn't know what you know there's lots of plant groups that you could show it to me and I'm like I just have no idea that's I don't it's a seed. Some of these fossil collections because somebody's sorting them out our marked things like possibly poop like we don't know right so so I think it's even we were lucky and that some paleobot and it said come along and been like fruit so that we could look through just the fruit fossils or seeds like they had gone enough to sort it out to that level. Many eyes have to come through over the years until our eyes came through and that those drawers those tubs of fossils are still sitting over there. There could be I don't know an apple seed fossil. I don't know what's over there but I you know that's not my area but I'm a soul nacy family and I personally wouldn't have thought I could do it and then she sent you know identify from little fragments, squished fragments of plant materials what this is I didn't think it could be this specific. But this thing was so obviously part of this group because around the base of the fruit chili peppers often have little fingers and so this fossil had those little fingers and I was like it's the K like's tea it's the little fingers this can only be one thing. This was the this was our moonshot we did it that's an incredible story it was very exciting it was very exciting do we need more botanists oh my gosh a hundred percent we need more botanists of 100 percent because you know there's so many plant groups where we're constantly discovering new species we know where they probably are but it just takes time science is a process and like I said you know we we applied for the money to go look for the fossils and we found the fossils then we had to analyze the fossils and published the data. So that whole business I mean has definitely been 10 years and so for one group of people working on one. group of plants. So, you know, the challenges that the need for this information is vast, you know, for, you know, all these AI searches that are trolling information. Who's information do we think they're trolling? The raw data that our labs are collecting and putting out the papers that we write. So, we don't advance as a society by continuing to troll the information that's already out there. New information has to be produced, new knowledge, and where is that knowledge in biology? It's outside. It's in the field. It's in museum collections. And so, we need eyes on that, measuring things, analyzing those data. And that's why fight hard to keep teaching botany as much as I can and hosting as many students in my lab as I can and really pushing to make opportunities for people to get to know plants and see how exciting and important they are and hope that some of them will want to spend their lives the way I do, which is like talking to plants, ground plants, studying plants. That is really wonderful. So, I would like to talk about the work your lab has been doing on convergent evolution. Convergent evolution is something that was so interesting to me when I took biology and I was reflecting on, you know, why? And I think it's actually, it happened later when I was studying archaeology and you learn that these different ancient societies who have no contact or maybe very little contact and not at the same time with each other are innovating independently. So, you have like the rise of farming happening in at least five different geographical places. You have writing, you have metallurgy, you have the wheel. And so, I always thought that was so fascinating. Like, you know, innovation isn't some magical thing that happens once. And then I sort of started thinking about evolution of species and traits and just I think it's so interesting that you have species that are not related, but they might end up evolving these traits that look similar. And so some examples are echolocation. So, bats and whales use basically sonar and, you know, bats are not really related to whales. They're in pretty different environments. Another one that's interesting is that fish in both the Arctic and the Antarctic have antifreeze proteins. You know, those species of fish are not related, but they're adapting to these similar challenges in their environments. You have this wonderful sentence on your lab website that said phenotypic convergence, the appearance of similar forms in independent lineages, provides an opportunity for testing the predictability of genetic evolution. So, I would love for you to tell us how you are looking at that in the context of the flowers. Right. Oh, those were such good examples by the way of the convergent evolution. I was like, oh, go on. Okay. I do have more. Although I do want to say about the repeated origins of agriculture around the world, the plant side of that I have to say is also super cool because then in many cases, the types of plants that were independently domesticated were similar types of plants, right? Grasses getting independently domesticated to make our grains at tubarous plants getting independently domesticated. And only some of these families make tubarous roots. And so I always tell that story because I think we talk about the origin of agriculture as if like it was invented someplace and it should be the origins of agriculture. And it's so interesting that that story of repeated innovation is all across our history and all biological history. And of course, our history is biological history like we're part of this big story. And I mean, I think much of it has to do with opportunity, right? That the pieces were coming together all around the world, allowing this to happen repeatedly. So in the case of agriculture, it's having some ability to cultivate plants, some knowledge of the plants that are around you, the foundation of communities where plants where you might be able to grow plant season over season instead of moving around so much. So I've always thought this story's fascinating. I tell it in class. And then so on the biology side, you know, I've always been very interested in converging evolution. How do you different completely different groups come up with the same solution? So there's this opportunity present and they present the same, what appears to be the same solution. And so you wonder if under the hood, is it really the same solution? How similar is it? Was there something? Did they stumble upon some way of doing this to let that open the door for them to evolve this new trait? Or were there so many ways to do it that many lineages could access this opportunity and come up with this response? So like in the plant world, we think about succulents. That's one of ours. So like the fleshy stems of cacti or other groups so that that's a response to aired environments. It's evolved a whole bunch of times. And there have been some spectacular examples where it was like just the same gene, but like the same amino acid, the same even the same nucleotide change happening independently. But that's not the common story. There's often predictable elements of it. So we set out to look at red flowers because red flowers are this classic case of evolutionary convergence. And I've been working on some other groups to try and estimate how many times they've evolved, but just like hundreds, let's just say hundreds. One thing that I really enjoy about science is spinning, allowing myself to have a thought experiment and thinking about what I think is going to be true while also being open to being so wrong. And I'm wrong almost every time. And so this was one of those wrong cases that I definitely enjoyed where I thought to myself, well, the easiest way to make red flowers would be to make red pigments, right? Pigments where if you put them into your spectrophotometer and measure their absorbance, you'll see that they absorb other colors and they reflect red, right? Red flowers, red pigments, that seems pretty straightforward. Why not? And it's not that nobody had looked at this before, but nobody had looked at lots of species. And we found that while some species do that, that's not the majority of species actually. Common ways to do it instead are to change the pH of the cell because pH will alter how the chemical interacts with light and plants and other organisms are regulating our pH, right? Because that determines how enzymes work in our body. So it's something we already had the ability to control. So again, it's evolution working with what it's got. So for us, when we're painting, I don't paint really, but red is a primary color, right? You don't make red by mixing colors. You mix colors like you mix red and yellow to make orange, etc. Plants, I don't know how this works, but they mix orange carotenoids like the chemicals that are in carrots that make carrots orange with purple anthocyanins, the things that make, let's see, like blueberries blue, but if you look at them, they're actually kind of purple. In solution, you combine the purple and the orange yellow pigments and it comes out red. Why not? Actually, yes, it should be brown. I know. Because I'm stuck in a painting framework here. Yeah. Yeah. Well, it's a very common way to do it. And I thought that was unlikely because that seems like doing it so hard. Oh my god. Why would you have multiple pigments involved? I think there's a couple of reasons. One is that petals are just modified leaves and what a leaves have chloroplasts that are making. Chlorophyll, yes, but they're also making carotenoids as accessory pigments for photosynthesis to pull in other wavelengths of light. So the genetic blueprint to make carotenoids and to make organelles that make carotenoids is all throughout petals. They had them genetic material and maybe it's not that hard to turn on. Maybe we don't know. And so anyway, I think that it wasn't that path was not as hard as I thought. And so it turns out red flowers, they're not made by an infinite number of solutions. There are relatively small number of solutions, but there are different ways to arrive with the phenotype and the way that I thought was simple and would be the obvious answer is not it. Plants are very happy to mix their colors. That is really neat. And it makes me think of I had just underlined the sentence and this interesting scientific American article that came out earlier in the summer and I'll link to it in the show notes. It's about, you know, how humans are actually still evolving. It talks about the statement that refers to what you had just said about the red flowers. So it says people in the Tibetan Highlands underwent selective sweeps for genes that helped them tolerate low oxygen. Intriguingly, populations of the Himalayas, the Andes, and the Ethiopian Highlands also adapted, but they did so with different assortments of genes, taking a different evolutionary path to solve the same problem. So again, you know, you might assume that during conversion evolution, all these organisms are coming on one mechanism, but that's another example of their different ways genetically, biologically, chemically to get to that phenotype. Yes, I think that what it tells us is if that ecological opportunity is there, like living in high elevations and organisms are repeatedly having the opportunity to try it out, multiple solutions will be arrived at. That, you know, the different organisms will bring their evolutionary history and be like, okay, here's what I have to work with. Here's what I've got. How can I meet this opportunity? Can you give us a window into what your research process looks like. So when you were looking at this question of what is behind the red flowers, what did you, what did it look like? What did you do, what kinds of experiments happened, etc. Yeah, that's a great question. I mean, that's one of the things I love about science is that you're doing so many pieces all the time. And because I've learned that so often, my thought experiment is not the right answer. I try to build in as many sort of back stops as possible to kind of just say, okay, am I really exploring getting all the data? Am I really looking as widely as possible? So the first thing we did is we picked a family to study, which is the tomato family that I study. It has 3,000 species, but only 35, 33 to 35 of them are red. And so I was like, we're going to go get all of them. So we read all of the literature and made sure we had a list of all of them. And then we went everywhere collecting these red species. I had a person in Colombia. I went to Peru. I went to Cuba. I'm like, all over the place trying to get as many of these because it needs to be fresh for us to get these pigments. So we need fresh tissue. Some of them we grew up from seed, to Mexico. It was really fun going to find all these things. And then what's so nice about pigments, we were talking about this earlier in studying them, is you can see the phenotype with your bare eyes. So you can, and actually even more beautifully under the microscope. And what's super fun and how I already knew I was getting in trouble, is that different pigments live in different parts of the cell. And so crotenoids only live in plastics, chloroplast, chromaplasties, things that you photosynthesis, but there are also other kinds of plastics. And they look like little blobs inside the cell. They're so cute. Depending on, depending on the species, they can look like little gold coins. They can look like little piles of dog food in carrots. They look like spindles. They, it's just, they're just wild. I love cromaplasties in general. I have such a fascination. So anyway, so we took a microscope to the field, and we would peel off the skin of the petal and lay it down on a microscope slide. And look and see inside these cells is the pigment uniform across the cell, which is to say that it's in the, the vacuole that holds all the water. That's the bulk of a plant cell is the vacuole that pushes out on the cell walls and makes it have a 3D shape. In that case, it's this, it's water soluble pigments. But if it's in little chloroplasts, if it's in organelles, then it's not those water soluble pigments. It's the hydrophobic crotenoid pigments. And so I already knew, aha, I, looks like I'm not right. That's the fun thing. And then you have to kind of break down hat. Okay, so what is the story? How did they get this way? And how does this work to make red? Is this really making red? And so we also took a machine that measures and quantifies redness, the spectrometer. We tried to come at this in a really quantitative way and let the data and the plants tell us what's going on. So it's really fun. So just sort of launch out, be like, here's what I think this is going to work. And let's collect all the data and really be sure. And of course, we did more chemical analyses, but you can see if you're wrong or right in the plant cell. And that's what I have students actually doing this summer. So now we're just launching to like every flower we can find. And so we're taking spectra and we are peeling off the skin and laying it on a slide and seeing who has what and we found such cool things like we found that forget me not have tannins, the same things that make red wine have that taste and tannins are usually not thought to be in flowers because why are tannins anywhere? They keep bugs out. So plants put tannins in wood and in skins of fruits to keep bugs out because bugs have that same reaction like that. It binds up proteins tannins do. What is they doing in petals? I don't know, but there they are. It was so fun. They look all sticky and globby inside of a petal too. And I was like, what is that brown stuff? It's a tan. Where in the cell are they? These actually are work extruded and they looked just like extra cellular blobs. That's what was weird is I was like, okay, it's not inside of vacuole. It's just kind of between the cells all gummy and sticky. That's where plants put defensive metabolites often between the cells to some little insects sticks its probossus in to try and attack and then they get attacked by the tannins. I'm not a red wine drinker, but the red wine drinkers are probably like, I'm familiar with exactly how that feels when I have a strong red wine on my tongue. Yes, insects like it less. Right. So exciting. Do you remember the first moment when you looked into the microscope and saw? Okay, these are not the pigments I was expecting. That is a really good question. I don't remember the first moment. I've been looking under the under under the microscope itself for so long. And I don't remember the first one, although I will say that one was so beautiful because the the petal cells they often form cones like circus tents because that's what makes petals look matte. And so yeah, so petals have that very plush carpety look because it is a carpet. The epidermal cells are like little like little circus tents perfect cones. So it was this carpet of pink, pink cells with orange chroma-plast, orange gloves all around the room of the cell. And it was so gorgeous that I I sent that picture off and it's it's it's on calendars now. It's on HHMI. You can freely download it. It was the picture of the day at HMI. And I think they don't get many plant pictures, but it's so captivating. It's funny because I don't know if any other lab in the world that does this that looks at petal coloration at the epidermal level across any species. Like give us any species and we'll check it out. And it's just you never know what you're going to find in there. So I I want to keep doing this. I don't know if we'll ever get money to do it. I don't care. Every student that will will do it. I'll train them. Oh, that's wonderful. I would like to ask another listener question. This is from Sam, age 16. He goes to peak to peak high school in Lafayette Colorado. And he asks, and I think we've covered this a little, but nice to just kind of answer it in one one place. What evolutionary pressures are responsible for the evolution of plant pigments? Thank you Sam for that astute question. When we think about selection pressures on plants, we always have to think about the fact that they can't move, that they are stuck in one spot. And so a lot of understanding plant phenotypes is thinking about all the things that they have to deal with. Cold, heat, wind, finding friends, sharing pollen with friends, not getting eaten. And so like if you have that mindset, you can then put forward all kinds of hypotheses. Like I have a friend who studied plant camouflage. And I don't know why I had never thought about plant camouflage, but then it was one of those, duh, like they can't move. And especially in arid places, where plants are holding all this water in their cells to do their biology. And they've done all this work to suck this water up from dry ground. And that is precious, right? You know, one defense obviously is to make a bunch of minds and be like, you touch me, you die, cover yourself with sticky stuff, let a plant do the other plants are real sticky, like you can't get me, you'll just, I'm a plant version of a fly trap. They are. But the other way is just to blend into the habitat. And so she did what people have done with vertebrates where they have, you know, ones that are light colored on the sand and dark colored on soil or lava or something. And then they move them and watch those poor lizards or mice get eaten when they're on the sprogs soil type. So my friend did that with plants. And she found that a lot of these plants that are in these really dry places are using pigments to try and blend in like nobody sees me, but it's such a balance, right? Because they have to figure out, I gotta get enough light to do photosynthesis, but I also kind of need to look like a rock. So like what a balance, like being just green enough to do the photosynthesis, you know, making just enough chlorophyll, but also having a grayish tinge. But so she found that yeah, herbivores things that come to eat plants, they don't see those grayish pigmented ones as well as they see the ones that got transplanted in from elsewhere. And we're more green, those got munched right up. So I think plants have this really complex balance. And unfortunately, as much as we would like to isolate a single factor, like just camouflage, that's not real life. Every organism is trying to do it all at once, oftentimes photosynthesis, not getting eaten, growing, trying to accomplish all of these things. That's why a lot of plants kind of give up at the reproductive phase when they switch into reproduction. It's like throwing off the cloak, right? All of a sudden they're like, oh my god, I got to make flowers. Everybody's going to see me and they're going to eat me. And a lot of plants just die after that. They're like, I give up. I've made it this far. I have made my flowers. All that needs to happen now is somebody brings me some pollen. I'm going to make some seeds and I'm gone because they're showing themselves. So that's why, you know, annuals are so common. They just flower and die. They put all this effort in. And we had a 30-year-old Yucca, some of these Yuccas. They live for a long time. They're not just annuals, but when they flower, that's the end of their life. So this giant thing sends out a, you know, 20-foot stalk to put its flowers on at the top to have moths and bats come at night. And then it gets the job done and the whole thing dies. It's amazing to me. I plant life histories are so fascinating, but I think that studying pigmentation, like studying any trait, you have to think about the whole organism and its life and what it has to deal with. And even if you study one little piece, like how do pollinators care about color, you can't stop thinking about the other pieces. And your point, you know, with even just one plant, depending on where it is in its life cycle, different things will be important. - I mean, just like us, right? - I know, I'm like reflecting as my daughter is, you know, almost 12, but I'm like, my good thing I'm so good with being uncool. Good thing I'm in the face of my life where I just don't care if I'm uncool. That works well for our family at this point. - Same, same, I'm such a dork, although my kids are younger, and so they still think I'm really cool, and I can just let it all hang out and they don't care, but I will brace myself for the stage where all of a sudden they realize, oh no, she's not as cool as I thought, but I think it all comes back around, right? Later, then they grow up and they're like, wow, mom was actually, like that was pretty cool. Like she was doing science. - It's freeing, yeah, 'cause you're like, it just doesn't matter. Okay, great, I don't care, I super don't care. (laughs) I want to kind of talk about some big picture reflections from your life in research. What do you like most about your job and what has surprised you most about it? - I love my job. I think it's incredibly lucky that I get to do a job that is like studying wild flowers. The thing that I said I wanted to do when I went to college and somebody's like, I don't even know what, that would be. (laughs) But even though I love plants and love being by myself and working on the science, I think the best part though is the people, is the community that I get to be a part of, and the community I get to build, right? So over my career, which I feel super old, I feel like that yucca, I'm sitting up the stalk, it's coming to an end, everybody. No, sometimes I get fatalistic. But I know people that study the tomato family like the all over the world, or part of this big family who studies the same family of plants, and I'm in a position to sort of, let people experience this plant excitement. I have a lab where people can come, and they can get to try out some of the things I've learned, how to do, I get to share what I've learned and all the skills, and also share this community. So I have students and then I can send them off to work with my other friends. And I think we're also united by the passion for understanding plants and how they work, and how we can have them serve people better in the ways in which they serve people, and just have people appreciate them. We're also united by that love that it's just an open arms kind of situation. Everybody's always so excited to talk to somebody else who works on something and shares a similar interest. So I love that part of my job. I love the teaching part of my job. Yeah, and the mentoring part of my job. It's kind of, honestly, it's kind of seamless. I feel like my students that I have in my class, I'm really just having a semester-long conversation with them. Some of it happens over pieces of paper, some of it happens in class, but it's an engagement in the same way that happens in my lab when someone comes in and says, "Very vaguely, I want to learn about plants." That's where they're at. I'm like, "Okay, awesome." I never turn away. Somebody who says, "I want to learn about plants." I'm like, "Walk this way. Come here." And then I guess the surprising bit, honestly, the surprising bit, and you'll appreciate this, Sue, is how much of success in this job relies on being a good writer. Wow, which I think can be, I don't always tell students at the start because it may be daunting. Writing and writing well is very hard. It's a skill that you've got your whole life. I get better at it all the time. I have to step away from my own writing and come back and look at it and go, "Okay, I'm not doing in this piece what I need to do. I'm not doing what I want it to do. How do I do it? It's a really hard skill, but it is fundamental." Commute, it's the way that I communicate broadly about what we learn. And if I can't write clearly, I'm probably not thinking too clearly and I'm probably not speaking too clearly. So it's all communication is really hard, but it is fundamental. And I've discovered that the people that communicate really well, that can bring their science to other people really well are the ones that are the most successful. And so I won't say that I always am ready to sit down and work hard on a writing piece, but I know I would do it more and more over time because what you realize, just like any other piece of science is the more you practice it, the better you are at it. And at that time, we'll be rewarded. And now, I more quickly see where I need to go and get my head in the mindset of like, "Okay, I know where I'm headed with this and I'm gonna bring the reader with me." So I think that the importance of being a good writer is undersold, but any scientist would tell you this, that most of their job is really writing. And the most important part of their job is writing. - I really love that perspective and it also surprised me to hear. Yet it makes a lot of sense because you're to become a scientist as a career, you're most often leading a lab. And so all of your communications are part of that leadership of keeping the lab going. - Yep, and then when we write papers and talks, I mean, all of that is where the rubber hits the road. Like, you know, what good is it if our lab knows it and the broader world doesn't know it. And the better you can express it, the more widely the message gets transmitted. And so it's been, now I view it as like, that's my central challenge. How to explain what makes me so excited about a chili pepper fossil that means you should be excited to. How do I put that into words? And I think we think like, "Oh, but you can write it really dry and boring "for scientists, they'll still read it." No, no, scientists want to read fun stuff too. So there should be no dry science papers. All science papers should be fun to read. And if it's not, then the writer's not doing their job well. - And you've done a great job on this podcast conveying the excitement of the chili pepper fossil. Well, I was very excited, so it's easy to do. - I noticed, Stacy, that you have a lot of undergraduate and high school researchers in your lab. How did that come to be and what has happened like? - I have so much fun. (laughs) I'm just saying people, in high school, there's really not an emphasis on plants. And so they come, all undergraduates in high schoolers come to my lab really fresh. They have exposure to plants that they eat at the dinner table, maybe they garden with a parent, but their understanding of the interworking, so they really just haven't had this opportunity before. And so they ask questions that I didn't see coming and push me to think harder about things. Okay, well, why is that? Actually, I don't know, maybe nobody knows. I should go see if anybody knows. The students in my lab this summer, they've been working on this question of, how do you make flowers different colors and what kind of pigments are there? So not just doing it for red flowers like we did. I guess what happened is once I realized that there were different ways to make red flowers, I were like, well, wait, okay, what are all the ways to make the other ones, right? How do you make the weird ones like blue and brown and orange, like what's inside of all of these? And so we've been taking that on together. And the good thing is that there's easy entry points that much of this begins with really simple observations. So I can give a little primer to how plants work and what's inside of them. And they can move on to doing their own experiments and collecting their own data very quickly. And so I think that's the key to giving someone a science experience is that they're not, you know, just washing dishes, they're collecting data. Although I will say that I never want to have people not realize that science is all of the stuff. And so everybody does all the stuff. You, you know, fill your own tip boxes to see what is it like to fill in the autoclave tip boxes. Like there's a lot around it. You don't walk in and it's like handed to you on a platter. You have to make your own sections to put under the microscope. Maybe they're bad and you have to make new sections. So like I have the students really do all the pieces. We have them up there potting seedlings and mixing the soil because to understand plant biology is to understand the entire plant organism and its life history. And so we need to be like, hey, what is this seed? I always say to my class, it's a baby with its lunch in a jacket. And so, you know, so we look, I'm just like, okay, where's the baby in this? What's the jacket? What's the lunch? How much lunch did this one bring? This one did not bring much lunch. So this is probably going to be a very tidy seedling. So anyway, it's really fun to teach in the lab. I wish that we could do that all the time, right? That we could learn right there hands on. And I tried to do that as much as I can in my classes. Although, you know, the janitorial staff, I'm sure don't want me having students pot in the classroom. They tell me today we're mixing soil people. Oh, God. Stacy, would you like to talk a little bit about your piece with Bated Breath? Yeah, so I mean, I think like a lot of us who work in science, people in the scientific community are aware that there are lots of threats to science right now. A lot of funding is being cut. People are losing their labs. People who already had grant money that they were going to do science with are getting that money taken away, which I don't think anyone would have thought possible. And so I think we've all been thinking about, what can we do? 'Cause should we go stand on the corner and put up a billboard? How could we get the most attention around science? So that people understand that this loss will be the loss of science in this country will be devastating for everybody, non-scientists and scientists select because we all rely on science. And so I've been mulling this over for a long time and there was a, as you well know, soup, kids in daycare or preschools in these schools. school, they catch tons of bugs all the time. They're always getting sick. And so my son had one of these routine, you know, they seemed like a cold whatever. He's not gonna go to school, but he doesn't seem too bad. He still has a lot of energy, five year old run around like crazy. What was strange about this one is that as the day progressed, it suddenly got really serious. And he had been with my husband in the morning, and then he came with me. I was taking over at lunch, 'cause you're swapping around between the parents. And I just noticed that he was gasping, you know? He was gasping and then saying a word and gasping. And I was like, "How do you feel?" Is your chest tight? His chest wasn't tight, and I called the doctor's office, thankfully they answered. And you know, trouble breathing is one of those things that you really don't mess with. And they're like, "We can't see him right now, so just take him to an ER." And we took him to the ER, and he wasn't pretty bad shape. So it seems that he had a strep infection that had swollen up his throat and was making it hard for him to breathe. And that's a scary deal. And they jump on it. And the first thing that they give anyone who is having difficulty breathing, it could be from like, "If you have a peanut allergy and you don't have your epipan on you, you need your throat opened up immediately so that you can get air." And what they do is they give you a adrenaline, but they have you in hailit so that it gets absorbed into your lungs immediately. And so they give it as a nebulizer. They stick this little thing in your mouth, and it gives you a whole fog of it that you breathe in. And it coats your lungs, and it makes that inflammation go down quickly. And then all of a sudden you can breathe. So they did that for my son. And I was sitting there thinking like, "Oh, thank God. Here I am freaking out that he's quickly becoming unable to take breaths. And this is really scary." And the respiratory therapist, the people that deal with difficulty breathing, was just real calm. He's like, "You know, came in due to do how are you today and plugs this thing in." And I was thinking, "God, what an amazing thing that we have something that can like, you know, on a dime open up somebody's airway." And I thought, "I need to write about this." Like, "What's the history of it?" So then I sat down and started reading about it, reading a whole scientific history of it. I thought, "Okay, I'm gonna figure out how did we get to this point, where my son walks into the ER, and they call on the respiratory therapist and they give nebulized up an effort." Just like, "Boop, here you go, 15 minutes later, doing better, gives us the time to say, "Oh, you need ibion, but actually I'm really best "drepo-bobla." And so anyway, it was fascinating. I got myself into this whole history of reading about it. And I really appreciated my scientific training because, you know, I don't work in humans. I certainly know work in physiology. I don't work in medicine. But I understand how scientific literature works. I understand how it's like a race, and people are relay racing. People are passing the baton to the next person. So I started just digging back in the literature to find out, well, who even figured out what epinephrine was? And how did they know what it was? How did they figure out how to administer? How did they figure out how much? How did they know if it was safe for children? So I pieced together this whole story, and I shared it on social media, and I was really lucky that a lot of people kind of picked it up and shared it and found it really impactful and could understand that people all the way back in the 1800s who were doing honestly pretty grotesque experiments with animals. Like if you're going to understand, a lot of our understand human physiology comes from animals and animal physiology. And so they were dissecting cats and dogs and injecting things. And it was pretty gruesome. But as a result, they figured out there's something in adrenal glands that has this kind of activity. And from there, it was a cascative. People finding the active compound, giving it to people making sure it was safe, et cetera, et cetera. And that was going all the way back to like, I think, 1890s was when the adrenal gland extract was identified to now 2025. And we've got completely widely accepted, safe, effective medication for this, what can be tragic, but totally treatable now situation. I think that shows that science yields rewards, but it's a long haul. And we have to invest in science not knowing what we're going to learn and why it matters. That's the big, that's the sticking point, right? People ask you why your science matters. And you know, I myself am often sort of triggered to give this responsive. Like I work on pigments and pigments are important sunscreens and they run on our diet. And they help us permit cancer, blah, blah, blah. But we shouldn't only invest in science when we know that it has this particular application that it's going to help us in this way. We have to do science of all types of organisms and all types of areas where we don't know what the consequence will be of having this new knowledge. Some of our biggest advances come from when we were studying things that had no apparent utility that were very distilling related from us in terms of the evolutionary tree of life. I think that's the thing we have to not lose is the mindset of appreciation for basic understanding of biology. We have to be not just looking where we think the answers are. We will not find the answers if we only look where the answers are. I know plants very well and my hypotheses are almost always wrong. So I don't look only where I think the answers are and nobody should. So anyway, I hope my piece helps. Pushes that a little. That's so well said, Stacey. What a wonderful quote about not looking where we think the answers are. Your piece is going to be published in the Wisconsin alumni magazine. Do you know when that will be? I think it's this fall. I don't know if someone's put this in a book. But I think there are tens, if not hundreds, of examples of scientific breakthroughs that came out of nowhere completely unrelated. I mean, the first one I think of now is the Heela Monster lizard spit, which now gives us our GLP-1 drugs that are so effective for diabetes and now for weight management. I'm not sure anyone thought that would happen when they were studying the spit of the lizard. And I mean, think of CRISPR. I mean, there have been whole tons of stories talking about the history of CRISPR. And it was all people going. These repeat sequences are really weird. And they're everywhere. And why are they here? So it just began with curiosity. No one was like, and this is how we will now do genetic engineering for the foreseeable future. That was not it. And I think that timeline moved pretty fast. But we never know how long the timeline is going to take. So we have to keep investing because we just don't know. Stacy, what path would a high school student take if they wanted a career in this field studying plants? What general advice would you give to them? My advice is that you'll have to create your own opportunities, especially at an early age because there's not that much plants. There's not that much plant biology in the curriculum. I mean, that's why I got to college and when they said you should be a biology major, I was like, oh, no, no, no. That was not it. Let me tell you. So I think gardening at home, joining four-h clubs, there's so many ways to get involved with plants. But it's an extra curricular that will then set you up for college classes. Most colleges have opportunities. I also think that people underestimate the degree to which their education is something that they shape themselves, that they can design their own classes for credit and have a faculty member run that class for them. Just as like a one-on-one, I do that all the time with students. So I think that it just-- you never know what answer you'll get when you ask. I mean, I went to Costa Rica as an undergraduate and worked on a stream, Ray Perry, and Reforestation project. And it was all because I just sent an email to a professor and said, you know, I really want to practice my Spanish and work on plant stuff in the tropics. And she was like, would you like to assist in this? I could send you. And I was like, of course, I would. So ask. Talk to people. Talk to people that have broader networks and see what your opportunities are. And don't be discouraged by the first person that says, I don't know what you do. Well, that person wasn't the person to talk to, but there's somebody. There's somebody out there. And I kept asking. And I kept finding opportunities to keep turning my path towards my passion. And that's my job, right? And that's every person's job is to keep turning their own path. You got to drive your own car here and find what you love and fight to do it. That is wonderful advice. It makes me think of when I was in college, I really wanted to do my senior project in archeological chemistry. And there was nobody in my college who was doing that. But I found someone at the art museum who had some artifacts. I found a professor in the material science department who would let me use a scanning electron microscope. I found a woman who worked at the art museum in Philadelphia and she did analysis of paints. And I was able to apply that. But it was such a wonderful moment to experience what you just described. Whereas if you really want to do something, first of all, I think people find your excitement really energizing and contagious. And they want to help you. But second, there are lots of people who might just have-- they have one piece that will help you. And then with a whole network of people, you can put something together. Right. I think the other piece is that when you're young, you have such a limited knowledge of what those careers could be. And there's so much pressure. I think on kids to be like, what's your major going to be? What are you going to do when you grow up? Oh my gosh, don't answer that question. Just say, I'm thinking about it. And I'll keep thinking about it for the next 15 years. And I'll let you know. Or change careers halfway through. So I think we as quilts-- Guilty. Yeah. Oh, I mean, I think-- - Like we as grownups were so curious about what kids are excited about, but we also need our main job to be to be allowed them to experience all the different things they can do and let them guide their own journey. So it's tough. I know I've asked my son and he says different things every time. - No, I meant like guilty because I feel like I've had like four different jobs, which has been good. I think it's wonderful. I'm boring by comparison. - Oh my gosh. You're going all over the world finding evidence of plant fossils. - Okay, that part's really cool. I will admit that's really, really cool. - Stacy, thank you so much for coming on the show. If listeners would like to learn more about your work, or I would say about plants in general, are there any good online resources? - Oh my gosh. There's so, there's so many good online resources. I admit that I follow social media content creators on plants. I think that's a great way to get going. There's tons of botanists that make such fun videos and will show you plants from all around the world and where they live and how they work. Paul Gonzalez is one of my colleagues from Peru who's watched a channel and he's one of these people. He's a natural. I am no good and he just, he just weaves these tales about plants of the Andes and shows you pictures and he's out the rain. And here's this thing flowering and a hummingbird comes out of the mist. And I also watch like home gargers who are so fun. So I think like plant content is everywhere. So just, you know, click follow on those videos and start exploring, start exploring. Yeah. And anyone can write to me. Like you say, Sue, people want to help other plant people. So anyone who writes to me and says, I'm excited about plants. I'm excited about these plants or this. You know, where, what should I do? How can I, I'm very happy to connect people. Stacy, thank you so much. Well, thank you, Sue. This has been so fun, so, so fun. Thank you for listening to today's episode of Science Fair. Please rate and review the podcast on the podcast player of your choice. Also, please fill out a listener feedback form. You can find a link to the form in the show notes of this podcast or on the Science Fair podcast website. Also linked to in the show notes. Finally, we are looking for episode sponsors. If you are interested in sponsoring an episode in exchange for us giving air time to your favorite cause, send an email to the science fair podcast at gmail.com with the word sponsor in the subject line. This podcast is the work of me, Susan Keatley and a fabulous team of interns. We have high school intern Lucy Poll, sound editing intern, Torin, Gerbaz, and episode production intern Sierra Rebels.