Urban Habitats

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Webinar: How Do Plants Breathe?
Aired April 7, 2022

Maggy Benson:
Welcome to Smithsonian Science How. We're so happy to have you here with us today. Welcome everyone. We're just going to give everyone a moment to join our virtual space here today. We're so happy to have you with us. As you're joining, feel free to find the Q&A space and tell us your name and where you are tuning in from. That Q&A space, we're going to use throughout today's program. We are going to ask you some questions throughout today's program and that's also a space where you can ask a very special guest scientist Nidhi Vinod questions.

All right, so we're going to give everyone just another minute or two to join our program. Hello. Thank you everyone so much for joining us. My name is Maggy Benson and I am a Smithsonian educator, a museum educator at the National Museum of Natural History. And today I am going to be facilitating our program with Nidhi Vinod, a plant scientist from UCLA and the ForestGEO program to learn about how plants breathe. I love plants. I have so many house plants. I love tending to my garden. So I am particularly really excited about this one. Now, before we get started, I just want to cover a couple basic logistics before we get going. So today's webinar, as a reminder, does not have video or audio for our participants. You can see and hear us, but you can't turn on your camera or your microphone.

So remember to use that Q&A space throughout today's program. We also have poll set up for you so that you can vote and see how some of your friends are voting on some of these questions that Nidhi has prepared for you. If you need close captions, navigate to the bottom toolbar in the Zoom window and select the CC button, show subtitles. And throughout today's program, we also have ASL interpretation. So thank you to our interpreter today for making this possible. All right, so we want to jump into this program and we also want to welcome some folks here today. We have friends from Hampton, Virginia, Illinois, we have Brantley from Maine. Welcome. We have Sophie from Darby. Welcome Sophie. All right, we have Courtney. Thank you all so much for joining us today. So without further ado, I want to invite our special guest, Nidhi Vinod to our program. Hi, Nidhi. Thank you so much for joining us today.

Nidhi Vinod:
Hello everyone. It's such a pleasure to virtually talk to you all and welcome to today's plant talk. I'm going to share my screen. All right, today, I'm Nidhi, we will go on a journey inside a leaf to investigate how plants breathe. Let's see. So how did I become a scientist? Around when I was your age or younger, I was so fat fascinated by the beauty of plants, the different shapes, the colors, the diversity all around me. So when I was little, I would go collect all these leaves, crush them up and try to see the different colors and pigments that came out of them. So I was very curious about plants when I was a little child. And as I grew older, I became more and more fascinated by those beautiful world. On the right you can see me in a beautiful meadow, a native meadow with goldenrods and rudbeckia hirta which are these flowers from Virginia.

And also I became so interested in leaves. So these are ginkgo leaves and they're really old. They're 250 million. They evolved 250 million years ago. And so I became fascinated by just how amazing this plant world is. Then I travel to different places. So plants are around all over the world, right? So I travel to different places. This is in Guatemala, and you can see how the trees look different. The mountain, the soils look different. So I travel from place to place to understand the different diversities of plants. And here I'm in Panama and you can see that this beautiful landscape, entire landscape, is covered by trees and grasses and flowers and whole forests. Can you imagine a world without these plants? And so just that cot made me fall in love with studying plants.

And then I went to the Smithsonian. I was an intern at the Smithsonian for a while where I got to ask questions. So being a scientist is asking questions. What are you curious about? What draws you to plants and how do you find answers? So I was able to train myself in this amazing, organization at the Smithsonian Conservation Biology Institute where we would hike in core trees and observe the diversity of plants. So when you're a scientist, you get to do the same thing if you go into studying plants. So now I'm have a question for you all. I'm sure you walked in forest. I'm sure you have observed plants around you. I'm curious about what interests you about plants, what draws you to plants?

Maggy Benson:
So a poll should have popped up on your screen so you can vote in that poll. And when you're done voting, if you want that to go away, you can just hit the red X. And we just want to hear what inspires you about plants. Is it their beauty? Is it questions about how they grow, all the different kinds or maybe the variety of colors, shapes, and textures that we saw in some of Nidhi's photos. And Nidhi I want to share that you shared an image from Guatemala and we have two friends here, Lucas and Adriana are from Guatemala today. So I wonder if they've seen some of those similar, beautiful landscapes that you shared with us.

Nidhi Vinod:
Yes. Welcome.

Maggy Benson:
All right. You're doing a great job voting. We'll share these results in just a moment. All right, we'll give everyone about five more seconds, five, four, three, two, one. All right. So here are results. It looks like people are inspired by all different things. They're interested in their beauty, how they grow, the different kinds and the leader among all is the variety of color shapes and textures. What do you think Nidhi?

Nidhi Vinod:
Wow, that's amazing because that's one of the first things I was inspired by too. So it looks like you are all scientists already. You're curious and you have wonder and all for the plant around you so you're all plant scientists, but today because we're all in the same room, we're all going to ask and participate and collaborate in finding an answer or a couple of answers to a question about how do plants breathe. So when we walk in forests, we know that sometimes we're gasping, we're taking in air and breathing out, but have you wondered how do the trees around you breathe? How do the plants around you breathe? Do you wonder? So we're going to find answers to this question.

Before I start that, let's do a small exercise. So we're going to all sit up right and we're going to take a deep breath in and then we're going to release it, to exhale. All right, so you took a deep breath in, but do you know what gas you inhaled? So you inhaled air, but there is a gas in the air that's called oxygen. So that's what you inhaled. And when you exhaled, you exhaled this gas that's called carbon dioxide. So you inhaled oxygen that is in the air and you exhaled carbon dioxide. So what do trees do? Trees do the opposite. So they take in what you exhaled, they take in carbon dioxide and they give out oxygen. And this is during the day. So during the day they take in carbon dioxide and they release oxygen. And in the night, they behave almost like us. They take in oxygen and give out carbon dioxide.

Maggy Benson:
So they do the opposite. They inhale one gas and exhale the other at one time a day and then do the opposite at night.

Nidhi Vinod:
Exactly. So now we're going to have a small question for you all based on what you just learned.

Maggy Benson:
Okay. We're just going to check our understanding right now. Nidhi just shared with us the process of how plants breathe and those important gases. So before we move on, and Nidhi reveals to us, how and why plants do this, we want to make sure that everybody knows which gas goes in during the day and which gas goes out at nighttime. So we are launching a poll right now. And the first question is, in the daytime, so think about in the daytime, what gas do trees take in and what gas do trees put out. And then in the nighttime, which gas goes in and which gas goes out. So this is going to be important for understanding more about how plants breathe as we go on in our program.

All right, we have some very clear winners right now. We have a lot of votes coming in. Well done. Just voting and thinking about this is successful. So don't worry about getting it right or wrong, just think about what you're thinking. And we will share our here and about five, four, three, two, one. Well done, everybody. All right, so we have two clear front runners. So our friends have said that plants take carbon dioxide in and put out oxygen during the day. So let's take a look at image. All right, so Nidhi that's correct.

Nidhi Vinod:
Amazing. Yes. You got it.

Maggy Benson:
And then at the nighttime, let's recap that again. So explain this to us, in the nighttime oxygen goes in?

Nidhi Vinod:
Yes. Exactly. So in the night it's the opposite, right? Oxygen goes in just like we do and trees release carbon dioxide in the night just like we do.

Maggy Benson:
All right. So well done everyone. All right, Nidhi, what is the connection here?

Nidhi Vinod:
Yeah. So now we learned about what the gases are that trees take in and give out during the day versus the night, but we still don't know how they breathe. Like for example, we have noses and mouths where we can take in these gases and give out gases. But have you seen noses on trees? Have you seen mouths on trees? No. So how does this gas go in to the tree? How does carbon dioxide in the morning go into the tree and oxygen out of the tree in the morning and in the night, how does oxygen go in and carbon out without noses and mouths? Well, they have leaves. So when you see a tree, a tree has millions and millions of leaves. So the leaves help the tree take in these gases and give out gases, isn't that amazing? And they can make these leaves every other day, every week, all the time, other than in winter. So leaves help trees breathe.

So now we're going to dig in even more deeper, but when you see a leaf, it's really flat, right? What does it have inside it that allows the gases to go in. So we're going to dig in even deeper. We're going to go inside the leave to find out what it has that allows it to breathe. That allows a tree to breathe. So we know that all leaves, there's so many types. We all mention that we love the shapes and colors and sizes of leaves. All these leaves allow plants and trees to breathe. That's amazing, right? You can manufacture your leaves every other day and that allows you to breathe so that's what happens. But now we're going to dig in deeper to see what is in the leaf that allows them to breathe. So we're all going to pretend like we're in a lab and you're all investigating. We're going on a journey to investigate how leaves help trees breathe.

So we're all going to take a leaf and we're going to put it on a slide. And now we have to use a microscope because we cannot see these minute things with our eyes, we need a special instrument, the microscope. So we put the leaf under the microscope and what do we see? We zoom in and we see these minute cells. You see an arrangement of all these cells. What are these cells? They're called stomata. So when you zoom in more, you see that some are open, some are closed, they're stomata. There are many types of stomata. What do these stomata do? There are like mouths, they open and close and they help the leaves take in the gases and release the gases. And that's how with all those leaves, having all the stomata, the trees can then take in the gases through these mouths and release gases.

But what is a stomata? How does it work? Well, in the day when it's really happy, in the day when the sun is up, it's happy. It opens it's pore. So there are two cells on both sides called guard cells. So it opens its pores. And then in the night, just as you would go to sleep, the stomata have done their work for the day and they close back up in the night and they close up as you see over here, but how does this allow them to take in the gases? What is their function? We're going to find out a little more. So let's say in the morning you have a beautiful garden. You're going to go out into your garden with your friends, your grandmother, you're going to water all your plants. So what happens?

The sun is up. Now the plants have plenty of water because you have watered them. And what happens? The stomata are happy, as I said, now that it has water and sunlight, the stomata is happy. It opens up. It's ready for the day. It's going to take in the food that it's going to get. And now it's going to take in carbon dioxide from the atmosphere. So now it's taking in three ingredients, the water, carbon dioxide, and the sunlight. So the leaf takes all of these three ingredients and makes it into the food that you eat. So that's where food comes from. That's where fruits come from. And do you know what this process is called? You might have come across this term.

Maggy Benson:
I wonder if some of our friends do. This may be a familiar process that you've had to learn in school before. So you can use Q&A if you want to tell us, we'll just give you a moment if you want to take a guess at what this is called. How these plants are taking in the carbon dioxide and turning it into energy to make food. All right, Sophia and Adam are the first to respond, but there's been several others Sophia and Daniel and Brantley, they've all arrived at the same answer, photosynthesis.

Nidhi Vinod:
Amazing.

Maggy Benson:
Daniel too.

Nidhi Vinod:
You all are great scientists. Exactly, photosynthesis allows the plants, the leaf to take in these ingredients and makes it into food. And so just as we exhale, the stomata also exhale out oxygen. At the same time, they release water. What happens to this water that comes out of the stomata? It accumulates and contributes to rain. So isn't this amazing one organ, one small cell can do so many things that can give us food. It can give us rain. It can take all these ingredients and make almost magic out of. So this happens during the day.

Another thing to remember is one stomata can take a little bit of carbon dioxide. What about having two stomatas can take a little more carbon dioxide. What about 20 stomatas? So the more stomatas you have, the more carbon dioxide can be taken in to the leaf. Okay. So what happens during the night? The night stomata close, the sun is not out. They don't have to photosynthesize, so they close up. And so instead of carbon dioxide, they take an oxygen because they don't need to photosynthesize and they release carbon dioxide. So now we saw that in the morning, they take carbon dioxide, in the night they release carbon dioxide. Well, one thing to remember is they release less carbon dioxide in the night than the amount they take in the morning. So they take in more carbon dioxide than they release.

Maggy Benson:
So Nidhi, this relates to somebody's question that came in a little bit earlier from Zee. How can we breathe at night if all the plants around us are breathing out carbon dioxide, would we die from breathing in the carbon dioxide?

Nidhi Vinod:
That's a good question, but not really because there is still so much oxygen in the night. Even though the plants are doing the opposite, there's still enough of oxygen in the night that we won't die if the plants are breathing just like us. And remember they take in a lot of carbon dioxide in the morning, right? And they give out a lot in the morning, a lot of oxygen in the morning. So all of that oxygen is still present all around you. So you're-

Maggy Benson:
That's a great question. And you really have people thinking about the stomata. This question comes in from Sophie. She wants to know how does the carbon dioxide get out at night when the stomata are closed?

Nidhi Vinod:
Yeah. That's another amazing question. So even though the stomata are closed, they're not like jam closed. They're not stuck together no way to open out closed. They can still slowly seep out carbon dioxide. It's also why there is less carbon dioxide released in the night than carbon dioxide taken in in the morning. Does that make sense?

Maggy Benson:
Yeah. Absolutely. So it's like a really deep breath in for this stomata and at night kind of tight, right? Just a little bit of carbon dioxide getting out. We have another question from Sophia and Adam, is this the same process that cyanobacteria use?

Nidhi Vinod:
Well, that is an amazing question for a cyanobacteriaologist. That's a good question to ask. I actually don't know the answer to it because I study plants mostly and not cyanobacteria, but if we know other cyanobacteriaologists, we can ask them, right Maggy?

Maggy Benson:
Yes, absolutely. So that's a great example of something that you can look up after this program to be able to see what process it is that cyanobacteria use to make energy and food and gas exchange, that's a key there. So Nidhi, you have taught us about stomata and when they open and when they close and which gases are going in and which gases are going out, but I know that you've prepared a couple of slides for us to pretend like we're doing your job for the day and really look at the stomata like a scientist.

Nidhi Vinod:
Yes. Exactly. So now you're going to be the scientist. Now we're going to give you leaves. People bring in leaves to you and they say, okay, I want to know which leave has the most number of stomata. So let's see if you can answer this question, investigate this question. So is it an oak leaf that has the most number of stomata or a maple leaf? I'll give you some time to count.

Maggy Benson:
Okay. We're looking at which leaf has more stomata. So you see the leaf on the left and you see a microscope image on the right. And maybe try to look at that image and count how many stomata you see. And we're going to pop up a poll in just a moment here so that you can vote and tell us which leaf you think has more stomata, right? So here you're looking at the oak leaf. Maybe we can look at the other leaf you have prepared. The maple now. All right. Now tell us which leaf do you think has more stomata and here you can see a side by side to compare it. So is it leaf A, the oak leaf or leaf B, the maple leaf? So this is a big part of your job, isn't it Nidhi? How you have to look under a microscope, look at these stomata make comparisons and do that a lot in terms of whatever you're researching.

Nidhi Vinod:
Exactly. Yeah. You would have sometimes two leave sometimes 20, sometimes 44 and you have to investigate, okay, which one has most, which one has least, what does this mean, so we're going to do a little more of that. So you're already on step one.

Maggy Benson:
All right. We have about a 100% answers in. So we are going to stop the poll and share those results. And 93% of you responded that the oak leaf has more stomata. What do you think Nidhi?

Nidhi Vinod:
Fantastic, yes, exactly. Oak leaf has most stomata. That's amazing. So now we're going to do another question. Let's see if we can tell if the stomata are open or closed, is it nighttime or daytime? So now we have a sycamore leaf and then we have a birch leaf with stomata on the right, the leaf on the left.

Maggy Benson:
Okay. So we're going to see if you can remember when the stomata are open and when they are closed. So we are going to launch a poll in a moment and we want you to tell us if this image of the sycamore leaf was taken in the daytime or in the nighttime. That poll is up for you now. And once you're done with that, you can move on the second question which is examining the birch leaf and telling us if it was daytime or nighttime when the image of the birch leaf stomata was taken.

Nidhi Vinod:
So we'll do A first.

Maggy Benson:
All right. We have a lot of votes in. Maybe we can show image B.

Nidhi Vinod:
Okay.

Maggy Benson:
All right. And we have just about all of our votes in 100% answer. So we will close this poll and share those results. And we, again, have two clear front runners. So in image A, the sycamore leaf, 100% of our friends said that it is daytime how'd they do?

Nidhi Vinod:
Amazing. Fantastic. Exactly. Yes. And little small thing I want to just mention, have you touched a sycamore leaf and have you seen how fuzzy it is? The fuzziness is because of all the hair around the stomata. So you can also see that in this image.

Maggy Benson:
That is very cool. All right and now our birch leaf, this one had about 87%. So this one was a little trickier said that it was nighttime.

Nidhi Vinod:
Yes. It's a little tricky because some stomata, as I mentioned earlier, do not close 100%. Some of them they're slightly tiny bit open, so it can be a little confusing, right? But it's nighttime. That's right.

Maggy Benson:
All right. Well done everyone. And even if you didn't get the right answer, that's okay. What matters is that you're making some of these close observations and voting and thinking about some of this information that Nidhi is sharing. So Nidhi, we do have a couple of questions that have come in. One question is, how do stomata close?

Nidhi Vinod:
Yes. How do they close is basically that it's not like they decide, okay, now I'm going to be open, now I'm going to be closed. So stomata are very dependent on the light. So when the light slowly starts to decrease and the dryness in the air changes, they slowly start closing. So if you put a leaf in the dark, if you put a paper, like a dark plastic bag with no light, the stomata also tend to start closing. And when you remove the bag and put it in the light, the stomata can start opening. The stomata have small sensors where they can also sense how much light is there. And so when you have a lot of lights, they can start popping open. Also, when they have a lot of water, especially water and light, start popping open and now they become open. And when there's no light, no water, especially they start closing. So that's-

Maggy Benson:
So we have two related of questions. So if the weather is cloudy, do the leaves or stomata close a bit. And related to that, how are plants breathing in the winter when they've lost their leaves? And also it's dark more often.

Nidhi Vinod:
That is such amazing questions. Oh, my God. I'm so impressed. So when it's cloudy, two things are important, right? So when the sun is out, the air also can be a little drier. So that allows the stomata to open. When it's a little cloudy, there is diffused light. You can see each other. It's not like we're blind to each other, right? So there's diffused light, but then you're right, the stomata won't necessarily be a 100% open some of the times. It's still open, but it won't be as happy and bright as it would be when it's sunny and when the air is dry. So that's a good question. And in the winter, yeah, there are no leaves, right? How do they breathe? So in the winter, that's a tricky question and we're learning a lot more about it, but in the winter, they store all the carbon that they have collected in the summer season when there is leaves and they can take in carbon and they've now stored it in the winter.

So they don't necessarily have to photosynthesize. They don't have to produce fruits. You don't see fruits growing on trees in winter, right? So when they drop their leaves, they're dormant. They're dormant and they're using whatever they stored in the summer to still continue to live. And again, when it's bright and warm, they start butting up new leaves and they can now photosynthesize, they can now bring in more carbon dioxide and start the cycle again.

Maggy Benson:
Well, everyone is really thinking about this because those were excellent questions. And we have several more really great questions that have come in. You've just answered Taya's question, which is that the stomata open with sunlight and diffuse light, right? But we have a couple questions about what happens when there is too much light hitting the stomata.

Nidhi Vinod:
Yeah. That's amazing. All these questions. So stomata are very, I would say, they are very sensitive to the environment around them. They are very sensitive and they react accordingly. When it is too sunny and when it is too dry, if you remember what also happens is the water is being released from the stomata, right? So I told you that stomata are very sensitive. So if it's releasing way too much water just also called transpiration, we didn't go into that, it's releasing way too much water. The stomata are like, oh, my goodness, I'm losing all the water that I have. Water is my life. Now I cannot let go of all of this water. So they actually start closing. And so they conserve the water so they don't have to lose all of it. So they start closing and that's how they're able to still maintain some amount of water within them.

Maggy Benson:
It's so amazing how sophisticated these leaves are. Okay. There are still so many really good ones in the chat, but we have one question that I think will allow us to move on to a couple more slides and we will keep all of these questions here in the queue and will get to them. But I think it was Tyler wants to know, how does a leaf have different stomata? And I think that's something that you're going to get to, isn't it Nidhi?

Nidhi Vinod:
Yes. How do different leafs have different stomata?

Maggy Benson:
Mm-hmm (affirmative).

Nidhi Vinod:
Yes. Exactly. So I will get to that just in the next slide.

Maggy Benson:
All right. Let's go on to that. And then we'll come back to some of these questions here. Great job everyone. You're really thinking like scientists.

Nidhi Vinod:
Exactly. And write down your questions in your notebooks. As you learn more, as you become a scientist yourself, some of these might not even have answers so you can be the one to find answers. So start writing them down. Okay. Onto the next slide. So just as there are so many beautiful images of stomata with different shapes and sizes in different leaves. Just as Maggy and I don't have the same kind of nose or mouth, similarly different plan have different kinds of stomata. So if you've seen a pine leaf, you can see pine on the left.

So pine leaf stomata are a little different than what you saw earlier. Then you have a fig leaf, have you all eaten figs before? Figs are delicious. So on the right, you have a fig leaf, they're smaller stomata, they're more densely packed. So different leaves, different plants have different strategies and have different kinds of stomata that all allow them to breathe. So now we have another question. This might be tricky, but maybe not to you all because you're all super clever. So the question is which leaf, I will show you a couple of leaves, which leaf would absorb more carbon dioxide from the atmosphere? Is it A or B?

Maggy Benson:
Okay. So a poll will pop up on your screen in just a moment and tell us, think about all of the things that Nidhi has shared with us about leaves taking in carbon dioxide and tell us which leaf will absorb more carbon dioxide from the atmosphere. Is it leaf A on the left or leaf B on the right? The votes came in very quickly and we have about 100% answered, I think, right now. So we can go ahead and share those results. Well, there we go. All right. So we have a clear front winner here, leaf B.

Nidhi Vinod:
Amazing. Yes. So more number of stomata you have, you can suck in more carbon oxide from the atmosphere, right? What about now? They're two different shaped leafs. Would it would be A or B absorb more carbon dioxide.

Maggy Benson:
All right. So you have a smaller leaf on the left, leaf A, and a larger leaf on the right, leaf B. They both have stomata, which one would absorb more carbon dioxide, leaf A or leaf B? Everyone is getting really confident. I'm really proud of everybody here. Those votes came in very quickly. All right. We'll close the poll in about five seconds, five, four, three, two, one. Okay. 89% say leaf A, the small one on the left.

Nidhi Vinod:
Yeah. Exactly. So even if you're small, you can do amazing work, right? You can take in a lot of carbon dioxide. You don't have to be giant all the time to take in the carbon dioxide because it depends on stomata, right? Amazing.

Maggy Benson:
Nidhi, are these things that you're actively studying in that plant scientist and you are actively studying. Are you looking at the number of stomata, the shapes of leaves, the sizes of leaves to be able to try to figure out why some leaves have more stomata than others and what that relationship is with carbon dioxide?

Nidhi Vinod:
Yeah. Exactly. So I am studying right now oak species. So a lot of oaks and we are looking at the structure of the leaf, the shape of the leaf, and how many number of stomata does the leaf have. What does this mean for the carbon dioxide and water, right? Especially carbon dioxide and water. What does this mean for the amount of water that gets released? The amount of CO2 that goes in? So these are exactly the questions that I'm studying. That's right Maggy. And we're going to go a little more deeper into that in the next slide.

Maggy Benson:
All right. Let's check it out.

Nidhi Vinod:
Okay. So now we know that all leaves have stomata. You all have done an amazing job in asking questions, really advanced questions. So now we're going to think about where does the carbon go? So now they're taking in all of the carbon dioxide from the atmosphere, where does this go? So the tree allocates it to different parts. Now this carbon dioxide is also used to grow new leaves. It's used to grow twigs. It's used for the whole crown, the branches, the roots, the trunks. So this is a very important gas and carbon to be allocating all across the plant's body, right? So what are some examples that you can think off of how leaf respiration or breathing or trees benefit humans.

Maggy Benson:
All right. So you can take a moment to put your answer in the Q&A space and we'll read some of those as they come in. So again, we're thinking about what are some examples of how this leaf respiration, this gas exchange, how some gases go in, some gases go out, benefit humans. All right. We still have a lot of questions coming in about stomata. Well done. We will get to some of those. All right. So we have one here from... Yes. Well done Daniel, they release oxygen for humans to breathe. We have more oxygen for humans. Helps with climate change by taking in carbon dioxide.

Nidhi Vinod:
Amazing.

Maggy Benson:
Yes. We have some questions about needing water, creating oxygen, more oxygen. Does grass have stomata?

Nidhi Vinod:
Yes. That's right. It does.

Maggy Benson:
Does cactus have stomata? That's another question.

Nidhi Vinod:
Yeah.

Maggy Benson:
In helping humans breathe. All right. Everyone is doing a wonderful job thinking about this. It's like water vapor, it goes into the atmosphere and becomes rain. We had another comment earlier about starting the water cycle.

Nidhi Vinod:
Yes.

Maggy Benson:
All right.

Nidhi Vinod:
Yeah. You mentioned a lot of the things. So it also gives us food, fresh apples, rain someone mentioned the water cycle. You're connecting the dots. Good job. Another one is shade. So there's a cool environment underneath the tree. How does it do it? It takes all the heat and releases it with the water. And now the place you're sitting under a tree is really cool. So respiration helps with that. And then many birds, insects, animals depend on trees for food. Leaves are like their homes and all the fruits and vegetables that plants and trees give benefit a whole ecosystem. So here's an image of that.

Also, you all mentioned they provide oxygen for us to breathe. That's right. That's super important. And someone also mentioned climate change, right? Carbon dioxide, taking carbon dioxide. You're thinking ahead. That's amazing. So yes, exactly. So when there is enough carbon dioxide in the atmosphere, a good amount, that's fine. We have our cycles going, the plants can take in carbon dioxide and make it into food and all of that. So it's good. What happens when there is excess carbon dioxide, but where does this excess carbon dioxide in the atmosphere come from, too much carbon dioxide.

Maggy Benson:
All right. Here's another opportunity for you to tell us what you think. What is contributing to the excess carbon dioxide in our atmosphere? We need some, but what's contributing to the extra amount? Cars, right? We're thinking about burning fossil fuels with that cars.

Nidhi Vinod:
Exactly.

Maggy Benson:
We're thinking burning fossil fuels. Well done. Air pollution, factories, greenhouse, maybe the greenhouse effect, volcanoes, pollution. So we have a lot of sources of other gas emitters usually through the burning of fossil fuel fuels or some off gassing with volcanoes. So what do you think Nidhi?

Nidhi Vinod:
Yeah. Exactly. So what happens with all of this excess carbon dioxide? Climate change. There's too much carbon dioxide in the atmosphere, right? So what happens is it becomes warmer or it becomes warmer around the earth, it becomes warmer. How does that happen? That happens because the sun rays are hitting the earth, it's warming the earth and the CO2 or carbon dioxide also called CO2 forms an invisible heat blanket. It's invisible. You cannot see, but it becomes a layer around the earth. And it traps all the heat within the earth making it warmer, hotter, and doesn't allow the heat to escape. So what does this mean? This means that many plants that are not used to hot climate will not survive too long. Some of the animals, some of the salmon mandus. So so many parts of the ecosystem are sensitive to really hot climate. So a lot of that also happens because there's excess carbon dioxide.

Another reason is because when we cut trees down, you all mentioned fossil fuels and burning as well, right? When you cut trees down, you don't have these large straws. Trees are like large straws sucking in carbon dioxide, right? So when you don't have that, what happens? There's no way to remove the CO2, carbon dioxide from the atmosphere. So more and more just gets accumulated in the atmosphere. So what can be used to take this carbon dioxide out of the atmosphere?

Maggy Benson:
So we've... All right. Trees.

Nidhi Vinod:
Oh, I gave the answer. All right. Yes. So trees. Exactly. So we need those trees. We need the trees to absorb the carbon dioxide, right? Like over here, you see, they do an amazing job taking it back out of the atmosphere. So leaving trees in the forest keeps the carbon in the forest available to be recycled back into the ecosystem. And especially big trees are very important in the world because big trees are like store houses of carbon. When you allow trees to grow their natural way into large sizes, they can now store so much carbon within them, so they're especially important.

This is the research that the Smithsonian ForestGEO does, understanding what big trees, how do they contribute to taking in carbon dioxide from the atmosphere compared to small trees? So just as we are asking questions, a whole worldwide network, all these yellow that you see are all scientist communities of ForestGEO, all across the globe asking these kinds of questions, connecting trees to climate change and asking the questions about gas exchange. Even the things you're asking about, stomata, right? And what is happening to this carbon, carbon cycle and climate change.

So these are the questions that scientists all across, you're seeing here, ask. And I myself did my internship, learned from my advisor in SCBI which is in Virginia about how trees respond to the heating of the world. So you saw that when there's so much too much CO2, carbon dioxide, the earth starts becoming hotter. So I learned about how trees are going to respond to this increase in temperature. So what do we do with all of this knowledge that you've learned? How does this help us? It helps us basically understand the role of trees, how important they are, why we need to preserve, what is happening on a leaf level like what are the processes that are helping us understand the cycle of carbon dioxide, so this is what the knowledge that you're gaining today helps you and me and all of us with. And also, we can then learn that by planting more trees, by working together as a large community of scientists, we can mitigate climate change from happening, right? We can try to reduce the carbon dioxide levels. So we work as a whole community. All right.

Maggy Benson:
Nidhi, it's wonderful to hear about this network of scientists working under that ForestGEO umbrella. That's a unit here at the Smithsonian to be able to study all of these different connections all the way down to the tiny stomata to the big forests and the big pictures and how things are changing and how plants respond to all different things like temperature and carbon dioxide. So it sounds like a wonderful research project to be part of.

Nidhi Vinod:
Yeah.

Maggy Benson:
We have a lot of questions still and a lot of questions about stomata. So if you're okay with it, maybe we'll stop your screen show and we'll dive into some of those questions. We have about 10 more scheduled minutes of this program.

Nidhi Vinod:
Yes. Definitely. Let me pull up a stomata screen just so you can all see.

Maggy Benson:
Also, everybody can look at it. Wonderful. So Sophia and Adam want to know why do stomatas have hairs around them? So maybe even look at that sycamore that looked a little furry.

Nidhi Vinod:
Yeah. That's a fantastic question because that's exactly also what I'm researching right now. So stomata don't necessarily have hair on them although they might, some might have hair, they have hair on them, right? So the hair are called trichome, they're another cellular structure they're called trichome and the trichome, they have many functions, but one of it is that when you wear a blanket in the night, doesn't it keep you warm? Exactly. So the trichome can also do that to, especially the leaves or the plants in cold places, gives them a little warm. And also it acts as a blanket to conserve water. So plants don't want to lose all their water quickly because they'll run out of water. So the hair act as a blanket to conserve water. That's a great question.

Maggy Benson:
So we have a lot of different questions about different kinds of plants having stomata. Do cactus have stomata? Do carnivorous bug eating plants have stomata? Do flowers have stomata.

Nidhi Vinod:
So usually anything that you see green, any part of a plant that you see that is green has stomata usually because it's photosynthesizing, it's taking in carbon dioxide and giving it to the part and it's photosynthesizing. So usually a lot of green surfaces have stomata. Yeah.

Maggy Benson:
Okay. And now a big picture question, you mentioned the ForestGEO network, this network of collaborators around the world that are all doing this plant research in forests, has the ForestGEO team found that leaves in some parts have more stomata than others, for example, perhaps a tropical versus a temperate forest.

Nidhi Vinod:
Yeah. That's a great question. I don't know if ForestGEO has done that research, but I know that there are several scientists communities that either have investigated or are investigating into whether tropical or temperate have more stomata. I don't know the answer to that. It depends on the climate. Sometimes when there is a lot of water, the plants can have more stomata so they can release a lot more... They can afford to release water, but when there isn't a lot of water available, they might conserve. So I don't know the answer to that one yet, but good question, write it down and you can learn about it or ask all the other plant scientists.

Maggy Benson:
Okay. We're going to go back into that stomata. Carrie, I think it was, wanted to know what is inside of a stomata.

Nidhi Vinod:
That's a great question. So a stomata is on a leaf, right? I wish I can pull up an anatomy figure, but a stomata is usually on top of the leaf. It's either on the surface, it's usually on the surface of the leaf. It's like an opening to go deeper within the leaf. It's like a door inside the leaf itself. So when you go beyond the stomata layer, then you move into the other cells that are beyond the stomata. So there you can find the cells that help the plant photosynthesize. So a lot of chloroplasts when you go even deeper and you can see where water moves into the leaf, xylem and phloem. So stomata is really just a top layer in many plants and that's a door to even go deeper into the leaf.

Maggy Benson:
Absolutely. Axel wants to know how these stomata were photographed.

Nidhi Vinod:
Great question. Oh, my gosh. I wish all of you were working with me in a way. So some of these pictures are taken by scanning electron my microscope. So this is a fancy microscope that shoots out electrons like these small atoms like electrons. Actually electrons, and then it gets a high very precise, very like the photos that you're seeing kind of a photo, but it's a very special instrument called scanning electron microscope. But the image that you see on the right over here, the maple leaf, that was taken under the microscope. So you can put nail polish on a leaf and peel it off, put it on a slide under the microscope and you can see the image on the right.

Maggy Benson:
Do you put the peeled off nail polish under the microscope or the leaf after you've peeled off a layer of a nail polish?

Nidhi Vinod:
Just the peeled off layer. Just the peeled off layer on the slide, still it has the leaf parts to it under the microscope.

Maggy Benson:
Yeah. That is very cool. Now the image that you showed us before that had color added to it, that's a great image. That's a great example of art neat science. And you haven't shared with us today, but I'm wondering if you'd be willing to share just a little bit about how your art is inspired by plants because I know that you are an artist as well.

Nidhi Vinod:
Yes. Exactly. I'm just always amazed by how detailed all plant parts are, like look at all those parts. So yes, I can share an image. Maggy, do you want me to share my screen or-

Maggy Benson:
Yeah, please.

Nidhi Vinod:
Okay. So let me stop sharing and then share again.

Maggy Benson:
Sure.

Nidhi Vinod:
Okay. I'll just do that.

Maggy Benson:
While you do that, we have a couple more questions that I think you've already covered. So Tyler wanted to know if bushes have stomata. Yes. Nidi said that everything that's a plant and green pretty much has stomata. And where does the water go, Si asked? And that's back into the water cycle, right? That turns into water vapor and it accumulates and eventually it'll turn into a rain cloud.

Nidhi Vinod:
Yeah. So depending on... So when you pour water on the plant, the plant takes the water up and uses it to function. And then also some of the water is released through the stomata into the air. And that guest comes back as water rain follows the hydrological cycle, the water cycle. Exactly. So let's share my screen.

Maggy Benson:
And Hannah wanted to know if pine stomata are pink, but that was really just the method that they took the photograph, is that correct?

Nidhi Vinod:
That is correct. Yeah. They're not always pink like that, that's just to highlight the stomata.

Maggy Benson:
It's a tool that scientists use to be able to look at something or call attention to something that they want other people to focus on.

Nidhi Vinod:
Yeah.

Maggy Benson:
Oh, wow.

Nidhi Vinod:
So I also illustrate a lot. So these are some of the drawings that I made of the veins on the leaf and I have some colored pictures. These are very quickly as I'm going through the day I paint, then I have very detailed images of... Do you know what this is? Anyone?

Maggy Benson:
Anybody know what that is? Look at the pattern, see if it looks familiar. Maybe look at some of the images around it.

Nidhi Vinod:
Yeah. So this is from a cone.

Maggy Benson:
Brantley got that right. Brantley said a pine cone.

Nidhi Vinod:
Yes. Exactly. So this is from a pine cone. When you take this apart, this is what you see the seeds of pine cones or this is cedar cone. And then I asked if you have eaten figs. So this is an image of fig that I've drawn and how wasps actually go inside the fig to pollinate it. Yeah. And I have whole I variety of images.

Maggy Benson:
Thank you so much for sharing your personal artwork with us. It's really incredible to see how beautiful these illustrations are. And you can tell that botany, that the study of plants is a true passion of yours. Just hearing you talk about plant respiration and gases and stomata and then seeing this wonderful artwork that's inspired by plants is really very inspiring. Thank you so much.

Nidhi Vinod:
Thank you all. It was so fun. I hope someday you can join me as a plant scientist and I'm excited to see all of your artwork if you're doing art. And I'm excited to see all the questions that you're coming up with one day, it will have answers, you will find answers shared with your friends, family, you can have a whole community of scientists.

Maggy Benson:
Absolutely. And yes, well done students. You did such a great job making observations and asking such wonderful questions throughout this full program. I hope that you feel empowered to investigate some of those answers yourselves after this program. So thank you so much for being here today and being so attentive. And thank you Nidhi so much for sharing your work with us both scientifically and artistically with us. A poll just popped up on your screen. You can rate our program today. And also when you close this Zoom window in your browser window, on your internet browser, a Zoom link will pop up or a survey link rather will pop up. We would really appreciate if you took that survey and tell us how you like this program so we can continue improving them for the future.

And also we will be sending an email with the recording of this video, if you want to watch it again, along with a short video about ForestGEO that provides a little bit more information about the way that they study forests on a really big global scale and some of the findings that they are discovering in terms of the connection of forests and climate change. So look forward to that in your inbox. And also just pay attention to the Smithsonian Science How eNewsletter and our website for more programs coming up in the next several weeks. So thank you all for joining us. Nidhi, thank you so much for being here and we look forward to seeing you all again on Smithsonian Science How?

Nidhi Vinod:
Yes. Thank you all.

Maggy Benson:
All right. Thank you all. We'll see you next time.

Nidhi Vinod:
Bye.

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• Biocube at Home is modified from the original Biocubes – Exploring Biodiversity activity to be done at home by individuals or family groups.

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