Listener Questions #47 - Plant Questions (featuring Dr. Manuel Lerdau)

Daniel and Kelly are joined by Dr. Manuel Lerdau to answer listener questions about toxic plants, seed germination, and micropropagation. See omnystudio.com/listener https://omnystudio.com/listener for privacy information.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Daniel Whiteson?

  This is an iHeart Podcast. Guaranteed Human.

• 0:04Speaker 01

  My name is Jessa. One of the things I love the most about working for United Healthcare is that everybody matters. Every moment matters. There's a person behind every problem. I care because it's what I was put on this earth to do.

• 0:20Speaker 02

  I'm Ben, and I work at United Healthcare. I am just one piece of a larger puzzle, but every piece matters. It's more than just work. We want to make the healthcare system better for everyone. I care because I want to make a difference. That's what committed to care means to me.

• 0:35Speaker 03

  If you're a custodial supervisor at a local high school, you know that cleanliness is key and that the best place to get cleaning supplies is from Grainger. Grainger helps you stay fully stocked on the products you trust, from paper towels and disinfectants to floor scrubbers. Plus, you can rely on Grainger for easy reordering, so you never run out of what you need. Call 1-800-GRAINGER, click Grainger.com, or just stop by. Grainger, for the ones who get it done.

• 1:05Speaker 04

  Small businesses are the pulse of every community. They bring people together, create opportunities, and drive growth. Chase for Business helps business owners like you with personalized guidance and convenient digital tools all in one place. With that guidance and your determination, you can take your business further and help build a brighter future for your community. Learn more at chase.com/business. Chase for Business: Make More of What's Yours. The Chase mobile app is available for select mobile devices. Message and data rates may apply. JPMorgan Chase Bank, N.A., member FDIC. Copyright 2026, JPMorgan Chase and Company.

• 1:47Speaker 05

  Hey, I'm Niall Rogers. This fall, I'll be driving across the country, meeting some of today's coolest and most fascinating artists. We'll explore the stories before the moments that changed everything. Because every musician remembers the moment where it all began. Experience Before the Moment, a Lincoln Original Series, on the iHeartRadio app, YouTube, or wherever you get your podcasts.

• 2:26Kelly Weinersmith?

  The Extraordinaries have requested information on plants that kill. Y'all are making me nervous, but I found a guest to fit the bill.

• 2:35Daniel Whiteson?

  Jane wrote in with a question about cues that seeds need to make them germinate, and wonders why not all seeds respond when they get the same message to activate.

• 2:46Kelly Weinersmith?

  Plants are weird, so Kelly says, but her husband wants to know. If I need an army of plant clones, how do I make them grow?

• 2:56Daniel Whiteson?

  Whatever questions are keeping you up at night, Daniel and Kelly's answers will make it all right.

• 3:02Kelly Weinersmith?

  Welcome to Listener Questions, episode number 47, featuring Dr. Manuel Lerdau. We found a plant guy.

• 3:22Daniel Whiteson?

  Hi, I'm Daniel. I'm a particle physicist who likes to think about aliens, and my family talks about science at the dinner table.

• 3:29Kelly Weinersmith?

  Hello, I'm Kelly Weinersmith. I study parasites and space, and my family talks about science all the time. Why are you specifying that you talk about it over the dinner table? I feel like there's something you're trying to get at here.

• 3:40Daniel Whiteson?

  It's not everything's a trap, Kelly. Oh, my gosh.

• 3:43Kelly Weinersmith?

  It is with you, Daniel. It is.

• 3:45Daniel Whiteson?

  No, I was wondering how a question from Zach ends up on the podcast. Is this a question that came up over dinner and you couldn't answer it, and you were like, let me put that on the podcast? Or how did it happen?

• 3:58Kelly Weinersmith?

  No, so I am a cruel wife.

• 4:04Kelly Weinersmith?

  And Zach was like, I heard about micropropagation, and it sounds really interesting, but I feel like that would be a better research project for you than for me, and I want to know more. And I was like, put it in the queue, buddy. He had to wait as long as everybody else usually has to wait, but his turn did come up. And so we are talking about micropropagation today.

• 4:24Daniel Whiteson?

  All right, because I also have a physics question from Zach that's near the top of the queue. That's also been a few months, unfortunately. So thank you to everybody who sends in questions, and especially thank you for your patience.

• 4:34Kelly Weinersmith?

  Yes.

• 4:34Daniel Whiteson?

  We have such a wonderful community of listeners and question askers, and it takes us a little while to get to your questions. We write back to people over email almost immediately, but doing the research and doing the recordings and getting it all edited takes a little while. Thanks for hanging on.

• 4:49Kelly Weinersmith?

  It does, yes. But we are so glad that you share your curiosity with us. And quite frankly, some of the most fun work that I get to do is digging into some of the questions that y'all ask that I would not get to read about otherwise.

• 5:01Daniel Whiteson?

  Absolutely. Totally love it. Sometimes I think we should do all listener questions on the pod.

• 5:06Kelly Weinersmith?

  I don't think I have enough time. It takes a long time to research these, but...

• 5:11Daniel Whiteson?

  But not when you punt the questions to your friend.

• 5:14Kelly Weinersmith?

  You know what? If we just want to keep having a rotation of Kelly's friends come through, I'm on board. We can do that. I feel like we should add a brief disclaimer that we did talk about biology, and sometimes talking about biology results in talking about the birds and the bees. Nothing too extreme in this episode, but you might want to be slightly careful if there are young ears around.

• 5:38Daniel Whiteson?

  We go beyond our usual poop jokes today.

• 5:40Kelly Weinersmith?

  Just a little. But yes, but we do. So, all right, let us wait no more. Let's bring my friend Manuel on the show to answer all the questions y'all have about plants. Dr. Manuel Lerdau is a professor in the Department of Environmental Sciences at the University of Virginia, and he is the Research Director of the Morven Sustainability Lab. Manuel works on loads of interesting topics, including decomposition, atmospheric chemistry, air pollution, global climate change, the impacts of invasive species, how plants defend themselves against pests, and so much more. Actually, I was not able to figure out a term I could use to describe what Manuel does because it is so diverse and awesome. He's also an avid birder. Welcome to the show.

• 6:22Speaker 07

  Thank you very much for having me. It is a pleasure to be here.

• 6:25Daniel Whiteson?

  You forgot his most important attribute.

• 6:29Kelly Weinersmith?

  You're going to say that he lives in Virginia, right?

• 6:31Daniel Whiteson?

  Well, that he's a former Californian.

• 6:33Kelly Weinersmith?

  Oh, I see. I see. Yes, welcome to Daniel and my long-running debate about whether or not Virginia or California is better.

• 6:41Daniel Whiteson?

  There's no debate. You just disagree with facts.

• 6:46Kelly Weinersmith?

  Well, you know, speaking about disagreeing with facts, Manuel, you wrote me a very polite email to let me know that you listened to our episode about how a species is defined.

• 6:56Daniel Whiteson?

  Oh.

• 6:57Kelly Weinersmith?

  And we did not at all capture how plant species are defined.

• 7:01Daniel Whiteson?

  Fascinating.

• 7:02Kelly Weinersmith?

  And as you pointed out, they make up the majority of biomass on this planet. So how would you define species? I'm putting you on the spot. You didn't know I was going to ask you this.

• 7:10Daniel Whiteson?

  This is an episode-level digression here.

• 7:14Speaker 07

  I'm glad to help.

• 7:15Daniel Whiteson?

  Nice.

• 7:16Speaker 07

  Well, for me, species are akin to, but maybe even more interesting than pornography in that...

• 7:26Kelly Weinersmith?

  Oh, great start. Great start.

• 7:28Daniel Whiteson?

  Wow. I had no idea where you were going there. All right.

• 7:30Speaker 07

  In that I may not be able to define them, but I know it when I see it.

• 7:34Kelly Weinersmith?

  Oh, got it. Okay.

• 7:36Speaker 07

  And so for plants, which is on the, at least on the land surface, that's about 90% of the biomass on the land. For plants, the whole notion of species is a little more complicated. And we're going to get into that, I have a feeling, later in the episode, when we start talking about how plants grow and reproduce and different ways to reproduce them. But I think that right now, what I would say for, if you were to hold a gun to my head proverbially, in Virginia, that's often literally.

• 8:12Speaker 07

  The definition I would use for a plant species is a genetic line whose appearance remains constant relatively through time.

• 8:28Daniel Whiteson?

  Oh.

• 8:29Kelly Weinersmith?

  Okay.

• 8:29Speaker 07

  And what I took out of there, from what we plant scientists call the zoological species concept, not the biological species concept, is this idea of reproducing and producing fertile offspring as the thing that defines a species. And the reason for that is that plants have raised, so to speak, interspecific promiscuity to an art form. And we did a study a few years ago, my collaborator and friend Chuck Cannon, where we looked

• 9:07Speaker 07

  across tropical rainforests and found that in almost every common group of plants, hybridization, that is, making fertile offspring across so-called species, was more common than reproductive isolation.

• 9:27Daniel Whiteson?

  Wow. So they were more likely to make offspring with other kind of plants than with their own?

• 9:31Speaker 07

  Yeah, and there's a very good reason for that in a tropical rainforest, where the diversity of species, so to speak, is so high. What that means, especially if you're a plant and you can't really walk around and find a mate, but if you're in a forest, let's say you're sitting in an acre, two or three acres of forest, and you're a particular kind of tree, because there are so many kinds of trees in that forest.

• 10:01Daniel Whiteson?

  Yeah.

• 10:01Speaker 07

  The chance that you will encounter, or your pollen will encounter, the female flower of your own kind is very small.

• 10:13Speaker 07

  And so we did this study, um, feeling very pleased with ourselves that we found this, that in fact, this hybridization is so common. And then of course, we learned, as so often happens, that this had been done decades before.

• 10:28Kelly Weinersmith?

  Oh, no.

• 10:29Speaker 07

  By a very famous plant biologist named Vern Grant. Who publishes, and then we found that it had been described even earlier than that. And in fact, they had already come up with a term for it, which is unfortunately not used anymore. And that is, and it's kind of jargony sounding, the syngamian. That is the sharing, the mixing of gametes of reproductive cells. So I try not to talk about plant species so much when I'm teaching as a plant syngamian. So for example, in Virginia, we have red oaks and we have black oaks.

• 11:13Speaker 07

  And if you spend any time out in the forest, you realize that a half to two thirds of the oaks you actually see are somewhere in the middle between the two.

• 11:23Daniel Whiteson?

  All right.

• 11:23Speaker 07

  And that's because they form a syngamian.

• 11:27Daniel Whiteson?

  So maybe we shouldn't think about California podcasters, Virginia podcasters. We should think of a podcast gamian blend.

• 11:36Speaker 07

  I'm not going to wade into your personal relations and how your various spouses might feel about these things.

• 11:44Kelly Weinersmith?

  Guys, I don't know what that implies behind the scenes is happening on this podcast. So I'm going to move on.

• 11:49Speaker 07

  But I will wager that a talented cartoonist could do something with this.

• 11:55Kelly Weinersmith?

  No.

• 11:55Speaker 07

  If you happen to know any.

• 11:56Kelly Weinersmith?

  I don't. And so we'll move on to the next question. No, I'm kidding. Obviously.

• 12:00Daniel Whiteson?

  Well, since you raised the question of spouses, I asked my spouse, who's a microbiologist, about plants and some of these questions. And she said that she thinks of plants mostly in terms of the microbes that live on them. And basically to her, plants are like apartment complexes to host the microbes. So they're basically just scaffolding for the interesting bits.

• 12:20Speaker 07

  Well, that, that's bit, I mean, I'm married to a musician. Um, so we have a different set of issues. But my experience professionally with microbiologists is that's how they tend to view plants, animals, everything that's not a microbe.

• 12:38Daniel Whiteson?

  Yes.

• 12:39Speaker 07

  It's simply a scaffolding for the microbes that they're interested in. And they're not necessarily wrong.

• 12:45Daniel Whiteson?

  Exactly what I was thinking when she said that. Am I also a scaffolding to you? Anyway, we're not going to dig into my marital issues on today's podcast. Let's answer the questions from listeners because that's why Manuel is here.

• 12:57Speaker 07

  That sounds good.

• 12:58Kelly Weinersmith?

  So first, we're going to start with two questions on a similar theme. And these are questions about poisonous plants. This is another line of questioning that makes me wonder if the extraordinaries are actually a big group of supervillains that are using Daniel and me and our friends for information about how to take over the world or kill their enemies. So let's go ahead and listen to those two questions now.

• 13:18Speaker 05

  Hey, Dean K. Love the show. Quick question. Do you guys ever get into the biology of deadly plants like scopolamine, the toura, that kind of thing? I don't remember an episode on plants specifically. So I'm just curious if it has ever come up or if it's on your radar. Thanks. This is Tan from Oklahoma City.

• 13:46Kelly Weinersmith?

  Howdy, extraordinaries. Listener Renix from our Discord community submitted a question, but then didn't have a chance to listen to the episode or record themselves. So I'm going to go ahead and read their question for them and then they can listen to the episode when they have some more time. Here's the question. Biology question for Kelly Wiener Smith. As a cat lover, I'm very aware that things that are harmless to me, like lilies, garlic, et cetera, are toxic to cats. I also know feeding sheep with high copper feeds meant for cattle can quickly kill them. Why is it that different things can be toxic to what appear to be relatively similar organisms? I'd expect differences between, say, a fish and a beetle, but it seems odd to me that it can vary significantly between mammals.

• 14:32Kelly Weinersmith?

  All right. So killing people with plants. So let's start simple. Why, why do plants produce toxic chemicals?

• 14:42Speaker 07

  Well, I mean, I think the easiest way to get at that is to think about all the things a plant cannot do. A plant can't run away. A plant can't really throw a punch. Some are quite good at tripping you, but um, on the whole, plants are stuck where they are.

• 15:02Daniel Whiteson?

  Yeah.

• 15:02Speaker 07

  And they don't move that much. And the world is a nasty, scary place. And you have to be able to defend yourself. And plants generally have two ways to defend themselves. One is what we call mechanical. So being really tough and strong, like the outer bark of a tree, or the spines on a cactus. And the other is chemical. And that is if someone's going to eat you, they're going to pay for it. And that's why so many plants are poisonous. In fact, pretty much all plants have at least one chemical to try to deter animals or fungi

• 15:47Speaker 07

  or bacteria from eating them. So we know about some of the poisons because they're famous in human history and have been really important for us. But really, all plants have something.

• 16:00Daniel Whiteson?

  This reminds me of something I read a long time ago about plant genomes. Something about how plant genomes are surprisingly larger than human genomes. And maybe because of all the complex biochemistry they have to do to produce toxins. Is there a connection there?

• 16:15Speaker 07

  That's a really interesting question. And even before we had genomes measured, the plant chemists knew something about plants that made them really different from animals, which is they have much more chemical diversity than animals do. And then in about, I'm going to get my dates a little wrong here, but I would say the late 1980s, two plant chemists, when they started looking at the genes underlying the production of these chemicals, discovered that in fact, plants have genes for more toxic chemicals than they actually make.

• 16:59Daniel Whiteson?

  Oh.

• 17:00Speaker 07

  So the genome is sitting there, ready to go in case they need to make a new toxic chemical. In case an insect who's a particular pest learns to overcome the toxin that's used, the plant can turn on something else.

• 17:20Daniel Whiteson?

  So not only do they have a whole storehouse of poisonous bits to throw at things, they have a backup library of other poisonous bits they can brew up in a moment's notice.

• 17:29Speaker 07

  Exactly.

• 17:30Daniel Whiteson?

  Wow. I'm scared of plants now.

• 17:32Speaker 07

  Yeah.

• 17:33Kelly Weinersmith?

  Yeah. So any of our extraordinaries who are supervillains should jump in the lab and start looking at what the plants aren't using yet and see what they can do with that.

• 17:41Daniel Whiteson?

  Isn't it amazing from that point of view that like any plants are edible?

• 17:44Speaker 07

  Well, in fact, if you look at wild plants, the vast, vast majority of them are not. And in fact, much of domestication of plants has involved making them no longer poisonous to us. For example, there are wild tomatoes growing throughout North and South America. All of them will kill you.

• 18:10Kelly Weinersmith?

  Whoa.

• 18:11Speaker 07

  And you don't want to ever eat a wild tomato. We domesticated them and we got the toxins out of them. If you've ever eaten a potato, you know that when the potato has green coming out, you don't eat the green. You always cut off the green. Why is that? That's the vestige of the toxin in the potato. We bred out, we've removed out by selection on the potato, the toxins in the part we eat, but the rest of it will kill you.

• 18:43Kelly Weinersmith?

  Wow.

• 18:44Daniel Whiteson?

  For those of you who've never eaten a potato, it's a delicious tuber you can find in many places, including California and Virginia. But does that mean that the delicious french fry has in it still the genome to produce poisons that would kill you?

• 18:59Speaker 07

  Exactly. It does. So the, the class of compounds that are in the tomato and the potato, they're very closely related, that will kill you are a set of compounds called alkaloids. And if you read Sherlock Holmes, you've run into that word. So if you look at the cells in the potato tuber, that which we're eating, they have the genes for those alkaloids as well, but they don't express them. They don't turn them on. And keeping those genes quiet is why we can go back to McDonald's more than once.

• 19:35Kelly Weinersmith?

  Even if it's not really good for us.

• 19:38Daniel Whiteson?

  So every time I eat a salad, I'm basically having to say thank you to the salad for not killing me because it basically has a gun pointed at my head and it's not pulling the trigger.

• 19:47Speaker 07

  Right. If we domesticated animals to slow them down so they wouldn't be able to run away from us like cows and pigs, we domesticated plants so they wouldn't kill us.

• 20:00Kelly Weinersmith?

  So do we know what those alkaloids do when they're inside of us to kill us?

• 20:05Speaker 07

  Um, I guess that answer really depends on what do you mean by we? There is an enormous field of study of how different plant toxins affect different animals and the ways in which they affect different animals. It's not something I know a lot about. I know a few of the really cute stories because they've been involved with things that I've worked on. So for example, I worked some years ago on one of the, on the tree that is most closely related to nutmeg.

• 20:42Kelly Weinersmith?

  Okay.

• 20:43Speaker 07

  Nutmeg, you know, it's a yummy spice. It has a beautiful, beautiful red fruity like thing called an aryl that surrounds it. And that aryl is quite toxic to people, but birds love it. And birds actually lack the metabolic ability to uptake that toxin so they can eat the aryl. And this happens quite frequently. So for example, um, actually in both Virginia and California, we have in Virginia poison ivy, in California poison oak. And they have these gorgeous light blueberries in the fall.

• 21:27Speaker 07

  And something in the name poison should tip you off not to eat them. But if you go in the fall, when the berries are ripe during bird migration, birds inhale those berries. They just love them. And they're actually very important nutrition sources for certain migratory bird species. Swallows, for example, and they're not bothered at all. So birds are really different from mammals in a lot of ways. One we don't think about as often is they can eat things that we can't.

• 22:04Daniel Whiteson?

  I love how toxicity is both dose dependent, right? How much of it you get and also species dependent. But can I ask a question about poison ivy? I've always wondered about because I once took a cross country road trip with Katrina from California to Chicago and we stopped and had a really nice picnic in what looked like a very nice field and then later developed terrible rashes and went back and found our pictures and we were like, oh my God, that was all poison ivy. But my question is like the delay, you know, I get that something tastes spicy or bites you or stings you. It teaches you not to touch it, not to eat it. But poison ivy, it's like, I'm gonna do nothing but put this on your skin and then days later,

• 22:46Daniel Whiteson?

  when you've forgotten who I even was, then I'm gonna make you suffer. So why the delay? It seems like very ineffective.

• 22:53Speaker 07

  First of all, I assume Katrina is the microbiologist in your life.

• 22:58Daniel Whiteson?

  She is, yeah.

• 22:59Speaker 07

  So just remind her of that story when she talks about plants as only scaffolding. They're also enemies.

• 23:06Kelly Weinersmith?

  Take that Katrina.

• 23:07Speaker 07

  But to answer your question, so that question has been around for a very long time and actually some of the very first colonial naturalists, you know, long before Darwin, were asking the question, what's the point of something that gives us a rash three days later?

• 23:26Daniel Whiteson?

  Yeah.

• 23:26Speaker 07

  And it is probably, we don't know this, we don't have great evidence for this. It's probably a side effect, not the evolutionary purpose.

• 23:37Daniel Whiteson?

  I see.

• 23:38Speaker 07

  Of the toxin. The toxin in poison ivy will make you very sick, very quickly if you eat the leaves.

• 23:46Daniel Whiteson?

  Yeah.

• 23:46Speaker 07

  Nobody does, so they don't realize that.

• 23:49Kelly Weinersmith?

  My goats do.

• 23:51Speaker 07

  Sometimes people will burn poison ivy.

• 23:54Daniel Whiteson?

  Oh no.

• 23:55Speaker 07

  And they get that toxin inhaled and they get very sick very quickly.

• 23:59Daniel Whiteson?

  Yeah.

• 24:00Speaker 07

  So it's probably actually not an intended purpose for this rash. And in fact, most animals, most mammals in the forest don't get rashes. The poison ivy oil doesn't actually ever even get to their skin.

• 24:16Daniel Whiteson?

  Well, my rash was bad enough that when I went to the dermatologist, she had the reaction of, hold on a moment, I have to go get my colleagues. I've never seen anything like this. And they all clustered around me.

• 24:27Kelly Weinersmith?

  Well, you're only telling part of the story.

• 24:30Speaker 07

  Yeah, I think this is kind of a family show. We might want to move on to.

• 24:34Kelly Weinersmith?

  Yeah, yeah. Okay, so you mentioned that birds can eat poisonous berries and they're fine. And so is there, can, I think probably the answer is obvious to a lot of people who know how like seeds get from one place to another, but, but let's just bottom line this. Why is it that plants are letting birds do that essentially?

• 24:53Speaker 07

  So a lot of the fruit that birds eat has very small seeds inside of them. And those seeds, especially the ones eaten by birds, are small and not particularly hard. But the skin, the outermost surface of that seed is chemically very tough. And so what happens is that seed is small enough and oddly enough, squishy, pliable enough that it can pass right through the bird's digestive tract and then come out in the poop. And one of the great things about many birds is that they eat, it takes them 10, 15, 20

• 25:38Speaker 07

  minutes to digest.

• 25:39Daniel Whiteson?

  That's it?

• 25:40Speaker 07

  By then they're somewhere else and that gets the seeds dispersed. That is how the plant who can, as we said, they're stuck where they are, that's how they get their seeds around is through bird dispersal. And birds, of course, fly and they tend to move farther than a lot of animals. So bird dispersal is a very efficient way to move your seeds around in the forest or the field.

• 26:06Daniel Whiteson?

  And I imagine a pile of bird poop is a great place for your seeds to land.

• 26:10Speaker 07

  It's pretty good. I mean, I think the real advantage is that you are far away from your mom. And there's a real advantage for plants and probably maybe other, maybe people too, to try and grow up far away from your parents.

• 26:28Daniel Whiteson?

  Really?

• 26:28Speaker 07

  And in the case of plants, and this comes back to the aforementioned Katrina, the advantage of growing up away from your mother is that imagine a tree who's sitting there for 200 years.

• 26:42Daniel Whiteson?

  Yeah.

• 26:43Speaker 07

  That's a long time for microbes and fungi to grow up and be around you. And those fungi that might not be too bad for an adult tree, that 200 year old one, would make life really hard for the baby. So there's what we call, to go into science jargon, negative density dependence. That is, the further away you can get from your mother, with a reason of course, the more likely you are to succeed. And this explains that pattern I mentioned earlier of having very high diversity in the tropical rainforest, right?

• 27:24Speaker 07

  Tropical rainforests are warm and wet, great places for fungi to grow. And so you don't want to be right next to your mom because she's probably hosting some fungi that would be really bad for you.

• 27:36Daniel Whiteson?

  So in the plant kingdom, there's no benefits to having a mom? There's no like protection or transmission of, you know, immunity or antibodies or anything?

• 27:46Speaker 07

  Oh, I mean, the, the plants also have sperm and eggs. And so anything that you can carry through in an egg, plants don't have the same immune systems, of course, as animals. So there's, you know, there's no, there's no mother's milk analog.

• 28:03Daniel Whiteson?

  Yeah.

• 28:04Speaker 07

  But reptiles and birds don't have that analog either.

• 28:06Daniel Whiteson?

  I'm just trying to stick up for moms here. I mean, somebody has to, you've been bashing them for minutes here.

• 28:12Kelly Weinersmith?

  Plants are different. I'm okay with this.

• 28:15Speaker 07

  No, I think, I mean, what plant moms do a very good job of is creating the environment around that seed so that the seed has a good chance to develop.

• 28:28Daniel Whiteson?

  All right.

• 28:29Speaker 07

  But they realize that maybe that seed doesn't need to develop with them.

• 28:32Kelly Weinersmith?

  Tough love.

• 28:33Speaker 07

  If you love your seed, disperse it.

• 28:37Daniel Whiteson?

  Wow, that advice works in so many ways.

• 28:40Kelly Weinersmith?

  So we've talked about how plants aren't necessarily producing toxins to go after birds because they want the birds to eat their seeds and distribute them. But then you get weird things like, uh, one listener pointed out that sheep, I think, can't have copper, but goats can, and that she loves garlic, but it would kill her cats. Is there an evolutionary reason for that level of specificity within like, sort of animals that have kind of similar strategies? Or is that just kind of bodies work different and throw up our hands?

• 29:11Speaker 07

  Um, a lot of it is bodies work different. So copper, I'm, I actually love copper. I didn't know you were going to bring that up. Um, we, we worked on copper in plants a few years ago, um, because it's sort of weird and mysterious there. Copper is really interesting because all animals need copper, right? You need copper, you can't do respiration, you can't breathe without copper. And copper is part of how the energy is transferred and compounds are made in respiration. And so everybody needs copper and it's toxic at high levels. So the amount of copper that you keep in your cell and where you put it in your cell

• 29:55Speaker 07

  at any one moment is incredibly tightly regulated. Because if you don't, your body will take up copper and it'll end up acting as a toxin. And actually, a lot of the reasons it's toxic at high levels are chemically the same that let it be so important at very low levels to keep you alive for respiration. So plants and copper are even more special, as you might imagine, because they're plants and so they're special, that copper is also used in plants in this really neat pathway. I'm going to jump into jargon for a moment again, because it's the name. It's called the ascorbate pathway.

• 30:41Speaker 07

  And if you're into human nutrition, you know that the ascorbate is vitamin C. And so plants have this very neat ascorbate pathway for dealing with very chemically reactive compounds that they make when they get stressed. So this ascorbate pathway is what keeps plants from self-poisoning. And it requires copper also. And so you need, plants need copper, some of it goes into ascorbate and some of it goes into what we call electron transport, that part of respiration and photosynthesis.

• 31:21Speaker 07

  And the reason that plants have to sort of have this special problem, it all comes back to the fact that plants are stuck and can't move around. And for almost all plants, how do they get their food? They capture sunlight and they use the energy that they capture from the sun to turn carbon dioxide into sugar. Now, the problem is, if you're a plant, you can't control how much sunlight you capture always. And sometimes there's more sunlight and thus you're trapping more energy than you can use to turn carbon dioxide into sugar.

• 32:04Kelly Weinersmith?

  Okay.

• 32:05Speaker 07

  And in that case, and we're getting really close to physics here, in that case, you have enough energy in there that you end up with singlet oxygen, not O2, but O, which actually becomes O minus. And that is really poisonous. And you need a special detoxification pathway to take care of that odd oxygen. And that's why plants need that copper in that ascorbate pathway is to take care of all the odd oxygen. Now, we get this, you know, if you go into your health food yoga store, you'll read

• 32:47Speaker 07

  about antioxidants and buy foods that are antioxidant. Well, that's the same thing. We make low levels of odd oxygen, but it's not really such a problem for us. Plants are producing this all the time when the sun is bright and they need a specialized chemical pathway for it. So they have things that are toxic to themselves, too.

• 33:09Daniel Whiteson?

  So that sounded like a lot of fascinating chemistry. I didn't hear any physics in there.

• 33:12Speaker 07

  Well, you know, oxygen, O versus O2.

• 33:17Daniel Whiteson?

  You don't get that without physics. Right, yeah, I guess physics is just perspective. So it's pizza night and I'm making my pizza with like 50 cloves of garlic on it. I always wonder when I do that, like, is there a limit to how much garlic you can put in your food? Can you poison yourself with garlic? Or am I free to just keep going to infinite garlic pizza?

• 33:40Speaker 07

  Um, I'm an empiricist. I would say, let's do the experiment. I don't necessarily want to be part of the experiment, but I'll read about it.

• 33:51Kelly Weinersmith?

  You'll be hard to replace as a co-host, Daniel.

• 33:54Speaker 07

  So the, the chemicals that make garlic taste good are the very same chemicals for most people. There are a few people who are unable to eat garlic. They react very badly to it. And there's sulfur-based compounds in the garlic. That's what gives it that strong flavor. And some people react very badly to that. Now, all of those compounds at high enough levels will cause problems. Remember I said that there are, and you used the phrase dose-dependent earlier. All plants have chemicals in them that if you eat enough of them, you will not be able to digest it and it will cause, at the very minimum, indigestion.

• 34:39Speaker 07

  My guess is that if you're able to eat garlic at all, you probably have some kind of dose dependency and at some point it would get too much and you would probably get sick to your stomach from it. The easiest example for people to know about is the fact that the chemicals in leaves that give them their toughness and structure, things called tannins and lignin. And all of these chemicals, what they do, tannins are the famous ones because tannins are what are in tea.

• 35:16Speaker 07

  And tannins are not exactly toxic to most organisms at reasonable levels, but they do inhibit the digestion of protein. So they make you a much less efficient eater. So imagine you're a bug eating a leaf. And as you eat the leaf, you want the protein in that leaf because you, your protein concentration is 10 to 50 times greater than the leaf. So you need to eat a lot of leaf to get your protein every day. You don't get it from milk or anything. So you're eating all that. That means you're eating all that tannin.

• 35:57Speaker 07

  That tannin actively interferes with your protein digestion. And so it's a trade-off. And of course, from the plant's perspective, the reason it doesn't just fill itself with toxins is that if it did that, well, then it wouldn't have chemicals for photosynthesis and for reproduction. So you always have to balance how much you defend yourself. Now, bugs are pretty smart, too. And what a lot of insects have figured out how to do is to have an early stage in digestion where they chemically modify the tannin before it interferes with protein digestion. So they've sort of worked around it.

• 36:40Speaker 07

  Humans don't have that workaround. So we can have our protein digestion very much inhibited by tannins.

• 36:49Kelly Weinersmith?

  Okay, let's send that answer on over to Tan and see what they have to say.

• 36:55Speaker 05

  Hey, Dinkay, that was excellent. I learned a ton. The bit about alkaloid gene just sitting dormant in potatoes and tomatoes and is ready to switch back on, that kind of blew my mind. So I will never look at french fry the same way again. Hey, keep up the show, make it last. I hope you guys never go away. Syndicate this thing if you can. Thanks again. Tan from Oklahoma City. Bye.

• 37:32Speaker 05

  Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's

• 37:40Speaker 04

  Fascinating artist. We're exploring the stories before the moment that changed everything. This week, I'm joined by Miguel. That last year, finishing that record was the hardest experience of my life. To find your creativity and to believe in yourself, because somewhere in the midst of it, I stopped believing that my voice mattered and that I could find it again. That's a challenge. I was not feeling very confident creatively, only, again, defiant in my belief that what

• 38:19Speaker 04

  this is about is express something honest. Say something honest. Experience before the moment. A Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts. This is Stugatz from Stugatz and Company Live. Buy smart, drive for less, and trade for more. That's Toyota affordability. And it all starts with a great deal on an all-wheel-drive Camry, Corolla Cross, or a Corolla sedan with the latest features and tech, or test drive a spacious Grand Highlander or adventure-ready RAV4. And with so many hybrid models available, you can enjoy longer trips without all the stops. While Toyota's legendary resale value

• 39:04Speaker 04

  means you can get more at trade-in. Get a great deal today and a great value tomorrow. Shop toyota.com for deals and details. Toyota, let's go places.

• 39:13Speaker 05

  The biggest game of the season, right here, right now. Starts Saturday strong. It's Big New Saturday on Fox. And here we go. It all starts at 10 Eastern with Big New Kickoff, live with an epic pregame. The crowd, the atmosphere, this is what makes it special. Then it's America's number one game. What a hit. The best pregame, the best announcers, the biggest games. Down the sideline, touchdown. It's Big New Saturday, noon Eastern on Fox.

• 39:43Speaker 03

  OnDeck is built to back small businesses like yours. Whether you're buying equipment, expanding your team, or bridging cash flow gaps, OnDeck's loans up to $400,000 help make it happen fast. Rated A+ by the Better Business Bureau and earning thousands of five-star TrustPilot reviews, OnDeck delivers funding you can count on. Apply in minutes at ondeck.com. Depending on certain loan attributes, your business loan may be issued by OnDeck or Celtic Bank. OnDeck does not lend in North Dakota. All loans and amounts subject to lender approval.

• 40:23Kelly Weinersmith?

  And we're back. And the next question is Jane from Red Car England. And so, Daniel, do you want to go ahead and get in your, you love Jane's accent?

• 40:31Daniel Whiteson?

  I love Jane's accent.

• 40:33Kelly Weinersmith?

  She has a great accent.

• 40:35Daniel Whiteson?

  Wonderful to listen to. It's melodic and harmonious. And it also just seems like she's having fun thinking about science. Nice to hear from you again, Jane.

• 40:42Kelly Weinersmith?

  All right. So let's go ahead and hear Jane's question. Hi, Daniel, but mainly Kelly. It's Jane from Red Car England again. Now, I know that I'm greedy, but I've got another question. What causes seeds to germinate? I know that some plants need fire to germinate, another needs several weeks below zero Celsius, sorry. And moisture and light also affect germination. But that's not what I mean. If you sow several seeds in the same conditions, not all of them will germinate. So what is the spark that sets it off? I presume that it's some sort of chemical reaction rather than divine intervention.

• 41:25Kelly Weinersmith?

  And once cell division starts, it is complex but understandable. But how does it start? Is it some random quantum process? In which case, Daniel should be answering after all. I'm still loving the show. You and Daniel, as well as being so intelligent and great science communicators, are just so much fun to listen to. Even when the jokes are painful and the poetry is more McGonagall than Keats, I always find myself smiling as I learn something new. So I can't wait to hear what your answer will be. Thank you. Always lovely to hear from Jane. And so, Manuel, let's start from the beginning.

• 42:09Kelly Weinersmith?

  What does germinating mean for those of us who weren't in intro biology for like 20 years or something?

• 42:17Speaker 07

  Well, I used to teach at SUNY Stony Brook, which is on Long Island, right outside of New York City. And we had a lot of students who were not native English speakers. And when I would get to germination in intro bio, one of the first points I'd have to make, I learned this only by not saying it one year, is it has nothing to do with becoming German.

• 42:41Speaker 07

  Completely independent of that.

• 42:42Kelly Weinersmith?

  Okay.

• 42:43Speaker 07

  So germination is a really interesting thing. And germination occurs when the plant in the seed form decides that instead of being in the form of a seed, it's going to be in the form of what we think of as a plant. Something with a stem, something with leaves, and something with roots, as sort of the stereotypical example. And that transformation, so it's genetically exactly the same, that transformation from seed to differentiate itself with leaves and stems and roots is germination.

• 43:26Kelly Weinersmith?

  Okay. So, so like, you know, with humans, when it's time to go from being like, I don't know, a fetus to a baby, there's like a nine-month window. And when that nine-month window passes, you come out of the body. And there's, so it's like a very fixed time thing. But with seeds, is it like you wait three weeks until you go from being a seed to a plant? Or is there different cues for that?

• 43:49Speaker 07

  So I guess I, I'm kind of going to push back on your idea that you go from being a fetus to a human being.

• 43:56Kelly Weinersmith?

  Okay.

• 43:57Speaker 07

  In a sense, when you're a mammal, as soon as fertilization occurs, you are developing. And you are initially just dividing, and then you're dividing and differentiating, and then all of a sudden, at some point, you're born.

• 44:14Kelly Weinersmith?

  Okay.

• 44:15Daniel Whiteson?

  And it's not like you're only linked to some internal clock, right? You're marinated in a bath of signals from the mom, right?

• 44:22Speaker 07

  And you're marinated in the signals. But if you're a bird or, or reptile, you start as an egg. But as soon as you fertilized, you are developing. Now, in many animals that are born from eggs, the rate that you develop is temperature dependent.

• 44:38Kelly Weinersmith?

  Okay.

• 44:39Speaker 07

  But you're always developing. Seeds are really, really different. A seed is a plant. It's not a developing organism along the way to a final adult form. It's an adult in itself. A seed is not a baby plant. A seed is a plant.

• 44:59Daniel Whiteson?

  A seed is an adult? That's mind blowing.

• 45:02Speaker 07

  A seed could be thought of as an adult.

• 45:04Daniel Whiteson?

  Wow.

• 45:04Speaker 07

  Right?

• 45:05Kelly Weinersmith?

  How so?

• 45:05Speaker 07

  A seed, there's fertilization occurs, and what happens after fertilization is that it becomes a seed.

• 45:13Daniel Whiteson?

  So in a plant democracy, seeds could vote?

• 45:16Speaker 07

  Well, the male seeds, yes. We don't let females vote.

• 45:20Kelly Weinersmith?

  Whoa.

• 45:21Speaker 07

  Well, remember, remember, we're in Virginia, right?

• 45:24Daniel Whiteson?

  Oh, wow. You're raining down the bombs over here.

• 45:27Kelly Weinersmith?

  I am retrospectively upset about the getting away from your mom comment, because now I'm seeing anti-female sentiment throughout all of this.

• 45:36Speaker 07

  No, no, no, not at all. Um, but it's an important distinction, both in ecology and in evolutionary terms, because that seed is something that in some species can survive for years, decades, centuries, even sometimes millennia.

• 45:54Daniel Whiteson?

  Amazing.

• 45:55Speaker 07

  And it is not that it is a plant frozen in development. It is itself what it is. Now, it's unique and different in that it's not drawing resources from the environment. It's not metabolically active.

• 46:11Daniel Whiteson?

  Yeah.

• 46:12Speaker 07

  And so it challenges our idea of what it means to be, quote, alive. Oh, it's a little bit metabolically active, not very. The question, I'll rephrase your question, Kelly. The question is, what causes a seed to decide to go from being one form, the seed form, to being that differentiated, quote, plant form, the leafy form?

• 46:37Kelly Weinersmith?

  Okay.

• 46:37Speaker 07

  And that's where things get interesting. Because for some plants, that decision is a chemical one, right? There are some seeds that need to, remember, we talked about the seed going through the bird digestive tract, or mammals, some mammals as well. That seed needs to pass through the physical and chemical scarification of its surface so that it can germinate. Other seeds need a certain period of low temperature before they can germinate. Still, other seeds need a combination of low temperature and water before they can germinate.

• 47:22Speaker 07

  Essentially, what it all can be explained by is that seeds are somehow able to use cues from their environment. It might be the intestinal tract of the bird, or the spring rain in the desert, as a cue to say, okay, this is a good time to go from being seed form to being leaf form. So that, that is what germination is. Little different than animal development.

• 47:53Kelly Weinersmith?

  And so why would you need the cold spell? What does the cold spell tell you?

• 47:57Speaker 07

  Well, think if you're, we've got, we're in July now, and in Virginia, and in California. You've got grasses now who are beginning to set seeds. And those seeds are going to see, at some point, rainfall. And if they say, oh, it's nice and rainy, let's germinate and grow. If they do that in October, in Virginia, they're going to be seedlings when it starts to freeze. Bad idea. They don't want to do that. So they say, okay, I'm going to need some kind of a low-temperature signal for a long

• 48:39Speaker 07

  period, months, before I turn on my water sensitivity. And of course, this is one of the great things scientists are trying to figure out now who work on seed germination is, what is that low-temperature sensor that they're using that says, okay, two weeks of low temperature were not enough to make me water-sensitive, but four months are? And what genetically is happening in that?

• 49:08Daniel Whiteson?

  But to bring us a little bit back closer to Jane's original question, you know, I think a common experience is you buy a bunch of seeds, you put them in the ground, you treat them all the same, they're in basically the same place, some germinate, some don't, some grow fast, some don't. Is that genetic variation among the seeds? Is that some sort of historical difference in seeds before they came to you? Or is there some quantum mechanical randomness where they're sensitive to cosmic-grade muons?

• 49:32Speaker 07

  So if you're buying your seeds at, in Virginia, we buy our seeds from Southern States Cooperative, you buy seeds who have received all the chemical and temperature treatment that that species of plant might need to be able to germinate when you put it in the ground and water it. So you put it in the ground, you water it, it is primed and ready to go. That's why you buy the seeds, is that you don't want to have to worry about letting them sit in your freezer or in your refrigerator over a winter. You buy them, you plant them, they grow.

• 50:09Daniel Whiteson?

  So this is something I didn't understand at all. You're saying seeds have a very complex set of germination requirements and highly variable. And when you buy seeds, all that work has been done for you, except for the last step, put it in the ground and water it. Wow.

• 50:23Speaker 07

  And so this is another thing that we did when we domesticated plants. A lot of the seeds you buy are domesticated plants, where we have reduced the number of experiences the seed needs to have before it germinates. Most domesticated plants, we've selected them to be very fast germinators.

• 50:44Daniel Whiteson?

  Wow, domesticating plants seems like a lot of work.

• 50:46Speaker 07

  Well, you know, we've been at it for a long time. We started roughly 12,000 years ago.

• 50:52Daniel Whiteson?

  Exactly. All right, so you were saying that purchased seeds are primed to go? All right.

• 50:58Speaker 07

  Now, some of them don't. And that largely occurs for a couple of reasons. One, those seeds were improperly fertilized to begin with, and the seed developed, but it wasn't really viable. And there's nothing you could have done to make it work. Sometimes, those seeds were fine, but maybe because they were so primed to go, some of them sat for too long. And they actually, they were a little bit too active in the seed form. Before I corrected myself, I said, they're not entirely inactive, the seeds, but they're largely inactive. But if they're, you know, they could be a little too much in the seed, and then they're not able to go.

• 51:42Speaker 07

  And some of it is, you think you're doing it all right, but you don't always do it all right. But one of the things that happens is that when people who sell seeds learn that certain ones are not germinating well from their customers, they often start doing things differently to try to improve that germination rate. And that, that's why it is so high. Now, you can see this same sort of thing in wild plants. You can collect acorns and do what you need to do to the acorn so that it will germinate. And different species of oaks have different requirements, they won't all germinate.

• 52:23Speaker 07

  Usually, that's because they didn't all develop along the way properly. And is that genetic? Is that environmental? It's really hard to say. I would say it's internal, but it could be genetic, it could be environment.

• 52:38Daniel Whiteson?

  But it sounds like if you have seeds with the same genetics, and you give them exactly the same experience, then you should get the same germination.

• 52:46Speaker 07

  Yes.

• 52:47Daniel Whiteson?

  There is no real randomness.

• 52:49Speaker 07

  No, this, this is one of the few cases where the physics, the muons are not that important.

• 52:54Daniel Whiteson?

  Although it underlies everything, of course.

• 52:58Speaker 07

  Absolutely everything.

• 53:00Kelly Weinersmith?

  So do you have any stories for like, the most complicated set of conditions that a plant has needed before it will germinate? Do you have like, a favorite example of a, a plant being high maintenance?

• 53:13Daniel Whiteson?

  And is it sequoia trees?

• 53:15Speaker 07

  You know, maybe it's because I've have and am still in the midst of raising up three high-maintenance offspring. But I think, I think the really interesting stories involve the low-maintenance ones. And I think that this, these cases, there's a, there's a lovely study still going on. And I think it's about, I think it's about 120 years old right now. It started about 120 years ago at Michigan State University, where they took seeds and put them in pots and buried them. Many, many, many, many, all identical. And they've been digging them up, I think it's every 10 years, maybe?

• 53:58Speaker 07

  And germinating from these pots, and seeing how germination rates change with time. And they're still getting incredible germination rates. And what's amazing in these studies is that they now have plants growing today who were adapted to the environment in East Lansing, Michigan, 120 years ago. And so they can actually study evolution by comparing these seeds from 120 years ago with seeds that come from individuals today. They can study how, what adaptations have occurred.

• 54:39Speaker 07

  And there have been similar kinds of works on people who find seeds. There was a guy who was actually not working on plants, he was working on ancient condors. You know, condors used to occur pretty far into the western United States. They weren't just on the coast. So he was studying condors, fossil condors, and ancient condors in pack rat middens in the Rocky Mountains. And he discovered seeds while he was looking for condor bones. And so they germinated some of these seeds. And these are seeds from thousands of years ago.

• 55:19Speaker 07

  So you can actually study adaptation in real time across centuries and millennia because of the ability of seeds to not germinate when the conditions aren't right.

• 55:34Kelly Weinersmith?

  What, but, and the seeds from the condor poop did germinate still?

• 55:39Speaker 07

  Well, they weren't in the condor poop, they were in the pack rat, you know, the, you know, pack rats have these middens, these little

• 55:44Kelly Weinersmith?

  Oh, yeah, yeah.

• 55:45Speaker 07

  Little tiny caves where they bring stuff, and they store stuff, and they had bones in there, and they had seeds in there. And so you can take these seeds and germinate them, and see what the plants from that time were like. And this is not long enough for new species.

• 56:00Kelly Weinersmith?

  That's cool.

• 56:01Speaker 07

  But it is long enough to see adaptation that changes in the environment.

• 56:04Kelly Weinersmith?

  That's awesome.

• 56:05Daniel Whiteson?

  All right, super fascinating. Shall we send this off to Jane?

• 56:08Kelly Weinersmith?

  We should send this off to Jane. All right, Jane, what do you think? Wow. Please thank Manuel for answering my question, which I'm stunned to hear is at the cutting edge of science. There were so many cool facts in this answer, like, a seed is a whole plant. I believe Manuel called it an adult in itself. And they're just primed and ready to go, just waiting for the right resources to kick things off. But I am relieved that we're not relying

• 56:39Speaker 07

  On muons. I didn't appreciate that commercial seed merchants prepared seeds so carefully. But that begs the question, if some seeds, as Manuel suggested, need to pass through the gut of a bird or an animal before they germinate, how on earth is this achieved commercially? Thank you once more for satisfying my thirst for more science knowledge. Hi, Kelly. Thanks for that interesting question from your rich. On the whole, this need for physical passage through an animal gut has been bred out of domestic planks. So when you buy seeds for flowers or vegetables for your garden,

• 57:24Speaker 07

  they largely don't need that kind of physical abrasion that they get by passing through the bird or the mammal intestinal tract. And that is one reason that many wild plant seeds have lower germination rates than domestic ones. The wild plant seeds are missing animal scarification that they may still require. One example where people on the East Coast of the United States or Europe can see this is with a plant called wineberry. Wineberry is a European kind of raspberry that is very common as a wild plant, but has never been domesticated. Wineberry rates of germination are much lower than the germination rates of domestic raspberries.

• 58:09Speaker 07

  There are some seed sellers who use physical abrasion to increase germination rate. You see this on the packet with the fancy word scarification. That usually means they just rolled the seeds around with some rocks to break up the seed coat a little bit. But of course, if any animals are used for scarification, it's likely goats, because as you well know, people who raise goats are lovely, willing to try anything, and sometimes a little wacky.

• 58:51Speaker 05

  Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything. This week, I'm joined by Miguel.

• 59:09Speaker 02

  My small experience with the discrepancy in the business of music made me angry in the best way. And I wanted to, I wanted to finish. So I started really like leaning into my therapy, trying to get down to like, what matters now? Somewhere Miguelito felt like he didn't have a place to say how he felt. And music was the place that I went to, to say how I felt.

• 59:31Speaker 05

  Experience Before the Moment, a Lincoln original series on the iHeartRadio app, YouTube, or wherever you get your podcasts.

• 59:40Speaker 04

  Hey, it's Covino and Rich Davis from Covino and Rich. Buy smart, drive for less and trade for more. That's Toyota affordability. And it starts with a great deal on an off-road ready Tacoma or half-ton Tundra, two of Toyota's most capable and longest lasting trucks. Combining power for work, tech for adventures, and style in between. Built on reputation for quality and reliability. Toyota trucks are known for holding their value, which can mean big savings when it's time for your next Toyota. So get a great deal today and great value tomorrow. Shop toyota.com for more. Toyota, let's go places. The biggest game of the season, right here, right now.

• 1:00:18Speaker 05

  Starts Saturday strong. It's Big Noon Saturday on Fox. And here we go. It all starts at 10 Eastern with Big Noon Kickoff, live with an epic pregame. The crowd, the atmosphere, this is what makes it special. Then it's America's number one game. What a hit. The best pregame, the best announcers, the biggest games. Down the sideline touchdown. It's Big Noon Saturday, noon Eastern on Fox. OnDeck is built to back small businesses like yours. Whether you're buying equipment, expanding your team, or bridging cash flow gaps, OnDeck's loans up to $400,000 make it happen fast. Rated A plus by the Better Business Bureau and earning thousands of five-star TrustPilot reviews, OnDeck delivers funding you can count on.

• 1:01:02Speaker 05

  Apply in minutes at ondeck.com.

• 1:01:05Kelly Weinersmith?

  Depending on certain loan attributes, your business loan may be issued by OnDeck or Celtic Bank. OnDeck does not lend in North Dakota. All loans and amounts subject to lender approval.

• 1:01:23Kelly Weinersmith?

  This last question comes to us from my favorite web cartoonist. Turns out I do know a good web cartoonist, and I'll change my tune and be nice here for a second. So Zach, go ahead and ask your question about micropropagation.

• 1:01:36Speaker 04

  Hello, this is Zach Weiner Smith. I'm a 90-year-old retiree from Japan. And I was just reading a book on horticulture, and I came across this idea of micropropagation, where somehow you use cells from plants to grow a bunch more plants. And I'm wondering, as are my friends here in Germany, exactly how that works. Thanks. Huge fan of, of the podcast. Good day, sir and madam.

• 1:02:10Daniel Whiteson?

  Zach is not just a web cartoonist. He's quite a gardener. I've been to the farm. I know he's like always involved in planting or growing something. Doesn't he have like a bunch of trees where he's like grafting this onto that?

• 1:02:21Kelly Weinersmith?

  He hasn't started the grafting yet, but that he has planted a bunch of trees and he plans on doing grafting. And he, he planted 60 pawpaw plots this year in the hope that he'll get to do some pawpaw grafting and, and stuff in the coming years.

• 1:02:36Daniel Whiteson?

  And so are you queen of the animals? And he's king of the plants? Is that how things divide over there?

• 1:02:41Kelly Weinersmith?

  That's right. And I thought that made me superior. But Manuel is pointing out that the biomass is in Zach's favor. But anyway, yes, he's, he's quite the gardener. He would say he doesn't know what he's doing, I think. But he's, he's learning as he goes.

• 1:02:54Daniel Whiteson?

  Would he?

• 1:02:54Kelly Weinersmith?

  No, I'm pretty not sure he would.

• 1:02:56Daniel Whiteson?

  You would say that he would say that.

• 1:02:57Kelly Weinersmith?

  All right. Well, I'm sure he'll weigh in on his comment at the end. So, all right. What is micropropagation? So Manuel and I agreed that I was going to try to explain this first and that then he would jump in.

• 1:03:09Daniel Whiteson?

  Nice.

• 1:03:10Kelly Weinersmith?

  So let's see how this goes. Okay. So, you know, folks who have houseplants know that sometimes you can cut off a piece of the houseplant and like stick it in soil or stick it in water, and you get a whole new plant. And so that is a way to get more plants quickly. But that's not fast enough if you want to be selling like thousands and thousands and thousands of a plant to people who, you know, there's a plant that's in great demand and you need to have a lot of them quickly. And so micropropagation involves essentially taking certain parts of the plant, sterilizing it so that you're getting rid of all of the bacteria, all of the fungus, et cetera. And then you put it in a little environment with hormones and other cues that the plant uses. And one of the things that you can do is create

• 1:03:54Kelly Weinersmith?

  in these like little containers with hormones is callus, where you get a lot of undifferentiated plant cells. So they haven't become leaves, they haven't become roots. They're ready to become something eventually. But at the moment, they don't really know what their future holds. And so you get lots and lots of these cells. And then you can break them up gently and put them into different containers with different sets of hormones. And each one of those will become a new plant. And so you can essentially have this stage where you're growing up a bunch of cells in an environment. You separate those cells out, you give them different hormonal cues, and now you can get thousands, maybe even millions of these plants much more quickly. What have I gotten wrong so far, Manuel?

• 1:04:38Speaker 07

  No, I think you nailed it. I think I was very smart to ask you to do this first.

• 1:04:42Daniel Whiteson?

  Kelly, you're an excellent guest on Manuel's podcast here.

• 1:04:45Kelly Weinersmith?

  Oh, good. Okay.

• 1:04:48Speaker 07

  It points up, I mean, let's go back to Daniel's potato there, right? It points up the fact that these cells throughout the plant are genetically identical. And it highlights one of the really interesting differences between plants and animals. It's a quantitative difference, not a qualitative one, which is that plant cells have a lot of flexibility compared to animal cells. And even though when a leaf develops, those cells that are formed by, you know, the cells are, are growing, they divide, the leaf, it's bigger and bigger and bigger.

• 1:05:33Speaker 07

  And those cells all become leaf cells. They're not fixed to doing that the way a lot of animal cells are. If you can pull those cells out of the leaf environment, and that's what micropropagation is, they become equivalent functionally to stem cells in animals. That is, they can then become anything they want. And you can grow them up in the right balance of hormones and sugar. Remember, they need a food source. You can grow them up into a new plant, and that's micropropagation. And the reason it works so well with plants

• 1:06:14Speaker 07

  is that this was called dedifferentiation, which is almost impossible with animal cells. Once you have a liver cell, it's almost impossible to have it become anything but another two more liver cells. On the other hand, a plant cell from a leaf, from a stem, can become that plant. Now, coming back to, oh, I forget who it was who asked about, about germination.

• 1:06:45Kelly Weinersmith?

  Jane?

• 1:06:46Speaker 07

  Jane, what you don't seem to be able to do in micropropagation is take that callus and have it develop directly into a seed. That doesn't happen.

• 1:06:58Kelly Weinersmith?

  Huh.

• 1:06:59Speaker 07

  And it's not clear why that is so impossible. But of course, you could imagine that if you were trying to grow something where the seed is the crop, it would be lovely if you could do that, right?

• 1:07:13Kelly Weinersmith?

  Yeah.

• 1:07:13Speaker 07

  Skip that whole step of the apple tree, just go apple to apple to apple.

• 1:07:18Kelly Weinersmith?

  Mm hmm.

• 1:07:18Speaker 07

  And that doesn't work. We don't, we can't do that. We seem to be only able to propagate from a callus, the leaf form of the plant. And nobody knows why that is.

• 1:07:30Kelly Weinersmith?

  Interesting. I bet if you could figure that out, you'd make millions, maybe billions.

• 1:07:35Speaker 07

  Right. I would not be on your, I would not be sitting at the University of Virginia, or on this podcast.

• 1:07:40Daniel Whiteson?

  You would be the plant king.

• 1:07:42Speaker 07

  No, I would still be on the podcast. I'd definitely be on the podcast, but I wouldn't be it.

• 1:07:46Kelly Weinersmith?

  Yeah, wouldn't be a professor anymore.

• 1:07:49Speaker 07

  I wouldn't be in the lab on a Friday, on Friday before July 4.

• 1:07:52Kelly Weinersmith?

  Okay.

• 1:07:52Daniel Whiteson?

  You know, if I made a billion dollars, I would still be a physical professor.

• 1:07:56Kelly Weinersmith?

  Well.

• 1:07:57Speaker 07

  It's, it's easy to say that.

• 1:07:59Daniel Whiteson?

  It was pretty easy to say that. You're right. But I think it is like, you know, this is what I enjoy doing every day. So.

• 1:08:05Kelly Weinersmith?

  So can you, when you're going to make that callus, can you take cells from any part of the plant? Or are there some cell types that work better?

• 1:08:14Speaker 07

  Well, there are some cell types where it's easier.

• 1:08:17Kelly Weinersmith?

  Okay.

• 1:08:17Speaker 07

  And a lot of that has to do with what kind of cell wall is around the cell. Another important way that plants are really different from animals is that plants and cells, in addition to having that membrane that we all have, also have a wall, a fairly rigid wall around them. So micropropagation, often, you want to work with cell types that have the thinnest, most pliable, most easy to degrade cell walls.

• 1:08:51Kelly Weinersmith?

  Okay.

• 1:08:52Speaker 07

  Because that's a whole side of micropropagation that becomes, that's tricky and important. It turns out that cell walls are a challenge for the plant as well, right? Because if you're going to divide and split, you have to break open your cell wall and then reform it around the new cells. And so plants have a whole really cool genetic system to essentially chemically degrade their cell wall just enough so it can split. But they don't degrade the whole thing because then they'd have to rebuild the whole wall. And they'd spend all their time doing that.

• 1:09:28Kelly Weinersmith?

  Okay.

• 1:09:28Speaker 07

  So in micropropagation, it tends not to get done on cells that have really heavy, thick cell walls, like the, the parts of wood that are really strong.

• 1:09:39Kelly Weinersmith?

  Okay.

• 1:09:40Speaker 07

  Those tend not to be used for.

• 1:09:42Daniel Whiteson?

  Right. That makes sense.

• 1:09:43Kelly Weinersmith?

  And then is it safe to assume that when you finish doing micropropagation, you end up with plants that are genetically identical to the plants that you took the cells from?

• 1:09:52Speaker 07

  Yes, they are literally clones of them.

• 1:09:56Kelly Weinersmith?

  Okay.

• 1:09:56Speaker 07

  Of course, if you do it for long enough, there can be some kind of small scale mutation that occurs along the way. But essentially, they're genetically identical.

• 1:10:05Kelly Weinersmith?

  Okay.

• 1:10:06Speaker 07

  I mean, the real challenge for micropropagation and why, you know, why not everyone does it, and why most people just cut off a leaf and stick it in, is that one of the very first things you said was really important, comes back to the microbes, that you have to do this in a super sterile environment. Because everything you do, when you are doing the micropropagation to help the plants grow, will help the microbes grow also. And what you'll end up doing is propagating an enormous microbial colony instead of a plant.

• 1:10:43Kelly Weinersmith?

  Okay.

• 1:10:44Speaker 07

  If you don't do it entirely sterilely. And microbes and plants have this incredibly tight relationship with one another, where you really don't, I mean, your, your wife is correct again, you don't have plants in nature, ever, without microbial infections.

• 1:11:06Daniel Whiteson?

  That's right.

• 1:11:06Speaker 07

  Ever.

• 1:11:07Daniel Whiteson?

  They're everywhere.

• 1:11:08Speaker 07

  That is the challenge in micropropagation, not so much the propagation techniques of cells, but getting the environment clean enough so that you can do it without micropropagating microbes simultaneously.

• 1:11:22Kelly Weinersmith?

  And is this part, so I remember at the end of micropropagation, there's a stage where you have to harden the plants back up again, because they've been in this like, perfect, sterile, delicate environment. Is part of that process, like reintroducing them to the, like organisms that they kind of need? Or is it just trying to toughen them up because they've been coddled?

• 1:11:43Speaker 07

  Um, it's interesting. I think probably one of the things that you're indirectly doing is toughening them up for the microbes.

• 1:11:51Kelly Weinersmith?

  Okay.

• 1:11:51Speaker 07

  But usually that hardening is more focused on the physical environment and the chemical environment that they're in, rather than the microbial, you just, you stop being so, so anally retentive about sterility, and you start letting them struggle a little bit more. And wherever there is carbon, there are microbes. And so the microbes get there.

• 1:12:18Kelly Weinersmith?

  Yay, microbes. So, all right. So some of the benefits of micropropagation are that you can quickly get a whole bunch of clones of some plant that you really want. And if you specifically are trying to make a plant that you know tends to have a disease, doing it in this sterile environment means that like, when you send this plant, for example, to another country, you can be pretty darn sure you're not going to be sending that disease to another country where it can then go and infect other plants. And so sterility is a feature, even if it makes things complicated. Does that sound fair, Manuel?

• 1:12:53Speaker 07

  Yeah. I mean, I'm not sure how much that sterile environment is important for, say, international shipping or interstate transport.

• 1:13:02Kelly Weinersmith?

  Okay.

• 1:13:02Speaker 07

  I think it's mostly important for getting plants who are not only genetically uniform, but have grown up in a really similar environment. If you have some who have been infected and some who've not been infected, they're going to be different plants. I've only been involved in one major study where we used micropropagation. And that was with a, we wanted the exact same genotype of a kind of tomato that we were working on. And we needed thousands of them to grow. And so when you're growing 7,500 tomatoes, you don't garden anymore for a few years. But we were able to do that. That, that was the

• 1:13:45Speaker 07

  main goal, was to get these identical plants so that we would know that any differences we saw were due to the perturbations we were exerting on the plants, not to differences that they came with.

• 1:13:59Kelly Weinersmith?

  I was listening to the In Defense of Plants podcast, and he was interviewing someone who does orchid conservation. And, and I hear that this is also like a helpful technique in some conservation programs for plants as well, where you want to grow up a lot of them, sort of as fast as you can, and maintain a bunch of genotypes. And so have, have you heard about this being used in conservation for plants as well?

• 1:14:19Speaker 07

  So it's pretty famous for orchids.

• 1:14:22Kelly Weinersmith?

  Okay.

• 1:14:22Speaker 07

  And the reason for that is that, one, people love orchids.

• 1:14:27Kelly Weinersmith?

  Mm hmm.

• 1:14:27Speaker 07

  Two, linked to one, a lot of orchids are quite rare. And three, because orchids have such intricate, complicated pollination systems, usually requiring a specific species of bee to pollinate that orchid, it's really hard to get orchids, many species, to get them to make seeds. Because your orchid from South America that you're growing in Albemarle County, Virginia, may not have the right bee.

• 1:15:01Kelly Weinersmith?

  Huh.

• 1:15:01Speaker 07

  And so your seed production will be low, so you can use micropropagation in order to get many others of your orchid. Now, you're only getting that genotype of that species of orchid, but it's better than nothing.

• 1:15:15Kelly Weinersmith?

  Yeah.

• 1:15:15Speaker 07

  So yeah, it's, in orchids, it's been hugely important. Anything that's really difficult to get pollinated, micropropagation would be good for.

• 1:15:24Kelly Weinersmith?

  All right. Let's send this answer to Zach and see if we have sated his appetite for knowledge about micropropagation.

• 1:15:31Speaker 07

  See if he's still awake after.

• 1:15:33Daniel Whiteson?

  I'll hail the king of plants.

• 1:15:35Kelly Weinersmith?

  Oh, no, I think the queen of the animals is the one that should be hailed.

• 1:15:39Speaker 04

  Hi, this is Zach Wiener Smith. I am a 95 year old retiree here in Geneva. And I just wanted to say I appreciated the thorough response. From Manuel and Kelly on The Kelly Show. Thanks very much for answering the question and au revoir.

• 1:16:02Kelly Weinersmith?

  Okay, and that's our episode. Thanks, everybody. If you have a question for us, you can send it to [email protected]. And some of the questions make it on the show, and the ones that really stump us, we bring our friends on to answer for us. So thanks for joining us today, Manuel.

• 1:16:17Speaker 04

  All right. Take care.

• 1:16:25Daniel Whiteson?

  Thanks, everybody, for listening. Please go and do us a favor and rate the show on whatever podcast app you're using. It really helps people find us.

• 1:16:33Kelly Weinersmith?

  Daniel and Kelly's Extraordinary Universe is edited by the amazing Matt Kesselman.

• 1:16:38Daniel Whiteson?

  He really is a wizard. You can also find us online on Blue Sky, Instagram, and X, D and K Universe. Come engage with us.

• 1:16:48Kelly Weinersmith?

  You can email us at [email protected]. We really do want to hear from you.

• 1:16:53Daniel Whiteson?

  And you can find our website, www.danielandkelly.org, where you'll also find an invitation to join our Discord, where everybody comes and talks about the amazing universe.

• 1:17:04Kelly Weinersmith?

  And we also have the most amazing moderators. This is an iHeart Podcast. Thanks for joining us.

• 1:17:13Speaker 05

  Hi, this is Mario Lopez from All Mario Lopez Daily Podcast. Buy smart, drive for less, and trade for more. That's Toyota affordability. And it starts with a great deal on an all-wheel-drive Camry, Corolla Cross, or a Corolla sedan with the latest features in tech. Or test drive a spacious Grand Highlander or adventure-ready RAV4. And with so many hybrid models available, you can enjoy longer trips without all the stops, while Toyota's legendary resale value means you could get more at traded. So get a great deal today and great value tomorrow. Shop toyota.com for deals and details. Toyota, let's go places. The biggest game of the season, right here, right now. Starts Saturday strong. It's Big Noon Saturday on Fox.

• 1:17:58Speaker 05

  And here we go. It all starts at 10 Eastern with Big Noon Kickoff, live with an epic pregame. The crowd, the atmosphere, this is what makes it special. Then it's America's number one game. What a hit. The best pregame, the best announcers, the biggest games. Down the sideline, touchdown. It's Big Noon Saturday, noon Eastern on Fox.

• 1:18:20Speaker 04

  Small businesses are the pulse of every community. They bring people together, create opportunities, and drive growth. That's why Chase for Business helps small business owners like you by offering personalized guidance and digital tools that can help your business grow. With our guidance and your determination, you can take your business farther and help build a brighter future for your community. Learn more at chase.com/business. Chase for Business, make more of what's yours. The Chase mobile app is available for select mobile devices. Message and data rates may apply. JPMorgan Chase Bank, N.A., member FDIC. Copyright 2026 JPMorgan Chase & Company.

• 1:18:54Kelly Weinersmith?

  Are you looking for support in your weight management journey? Zepbound Terzepatide may be able to help. Zepbound is a prescription medicine used with a reduced calorie diet and increased physical activity to help adults with obesity, or some adults with overweight who also have weight-related medical problems, to lose excess body weight and keep the weight off. Zepbound is approved as a 2.5, 5, 7.5, 10, 12.5, or 15-milligram injection. Zepbound contains Terzepatide and should not be used with other Terzepatide-containing products or any GLP-1 receptor agonist medicines. It is not known if Zepbound is safe and effective for use in children. Don't share needles or pens or reuse needles. Don't take if allergic

• 1:19:37Kelly Weinersmith?

  to it, or if you or someone in your family had medullary thyroid cancer, or if you've had multiple endocrine neoplasia syndrome type 2. Tell your doctor if you get a lump or swelling in your neck. Stop Zepbound and call your doctor if you have severe stomach pain or a serious allergic reaction. Severe side effects may include inflamed pancreas or gallbladder problems. Tell your doctor if you experience vision changes before scheduled procedures with anesthesia. If you're nursing, pregnant, plan to be, or taking birth control pills. Taking Zepbound with a sulphonal urea or insulin may cause low blood sugar. Side effects include nausea, diarrhea, and vomiting, which can cause dehydration and worsen kidney

• 1:20:14Kelly Weinersmith?

  problems. Talk to your doctor. Call 1-800-545-5979, or visit zepbound.lily.com. This is an iHeart Podcast. Guaranteed Human.