2023-11-19 by Khushi Goel

[Transcript] IndiaAsksWhy | Why Do Flowers Bloom?

Listen to the episode, here

0:06 Both: Hi, everyone!

Utsuka: I’m Utsuka

Jigyasa: I’m Jigyasa

U: You are listening to IndiaAsksWhy Season 3 supported by IndiaBioscience Extension Grant.

J: At IndiaAsksWhy, we love to chase our curious science questions!

U: This season, listeners from across schools are joining us on our curiosity-chasing endeavor. So let's get started. Shall we?

0:36 J: We all love the colorful blooms of flowers in our surroundings. They always lift up our moods and decorate the place. One evening, Utsuka and Jigyasa were enjoying their time in the garden with their friends, Anushka and Hamsini from DPS Secunderabad. This is when they wondered, why do flowers bloom?

Join the curious group as they chat about the reasons for flowers blooming and the inner workings involved in the blooming of flowers.

They also spoke to Dr Mukesh Lodha, a plant scientist who specializes in the molecular mechanisms of flower blooming and has a special lab where they grow plants. They also spoke to him about his motivations and inspirations for choosing the path as a plant scientist.

1:32 A: Oh, wow. Look at all these amazing flowers, roses, hibiscus, jasmine. Hamsini look! There is even a daisy here.

1:42 H: They are such a colorful treat to our eyes. I can just stay here all day, Anushka.

1:48 A: I know looking at all these blooming flowers makes me think. Why do flowers bloom?

1:54 H: That's an interesting question. I'm curious to know also, how do flowers bloom?

2:03 A: When we have curious questions, whom do we ask? Utsuka and Jigyasa?

2:07 J: Wow, you both have asked very interesting questions. It's now time to find out.

2:16 U: Flowers have fascinated humans for thousands of years. Plant scientists have spent countless hours understanding them.

2:26 A: I'm sure. Let me first ask my question. Why do flowers bloom?

2:31 U: Let's start with the basics of flowers. You've studied flowers in school, right? Yes, we learnt the parts of flowers in school, like the petals, the green sepals and male and female reproductive parts.

2:46 H: Exactly. The male parts carry pollen and the female part carries the eggs.

2:52 U: Yes, that's perfect. Flowers are one of the most important parts of a flowering plant. Can you guess why?

3:05 H: They help in the formation of seeds..

3:08 A: …and seeds give rise to new plants. This ensures that a plant species continues to exist on a planet.

3:12 U: Exactly. Flowers are essential for reproduction and continuation of a plant species.

3:23 A: and flowers opening, blooming helps in reproduction, somehow.

3:24 U: There you go. When flowers open, they expose the pollen to wind, the wind transfers the pollen to the female reproductive part. Can you guess how else colorful blooms might help the flowers?

3:39 H: The color of petals can attract insects or any other animals to do the transfer.

3:47 A: But what causes the flower petal to actually open?

3:51 U: How a flower actually opens varies from species to species. For example, in some plants like hibiscus and rose, cells that are in the middle of the petal divide more compared to those on the side. This uneven growth causes the petal to open. Sometimes the water gets unevenly distributed, which helps in the opening and closing up of the flower.

4:18 A: Interesting. But flowers don't bloom all the time, right?

4:23 U: You're correct. They only do it when it's the right time to reproduce.

4:31 H: That makes sense. This brings me to my question: How does the flower know it's the right time to bloom?

4:43 U: Since flowering is so important, it seems like there is a common flowering process in all plants. As Professor Lodha, the plant scientist on call said there are three parts to this process.

4:53 Prof Lodha: So let me divide the flowering process in three parts.

4:57 U: Let's go through them one by one. So for this, I want you both to imagine yourselves as your favorite plants. So, Anushka, what do you pick?

5:09 A: Sounds fun. I pick sunflower. U: …and Hamsini? H: I pick Jasmine. U: My first question to both of you: Would you like to flower whenever you feel like?

5:26 A: No, as a sunflower plant, I would only like to flower when I receive enough sunlight favorable to reproduce.

5:30 U: Exactly. The first step is collecting cues from the external and internal environment.

5:37 L: So the first part is the decision making part. So plants usually take a lot of cues from the environment, light temperature. All these things, they take cue, they also take you from their age. Are we ready to flower? So all these internal and external cues actually are first collected. So this is step number one.

H: But there could be so many cures, right? As a jasmine plant, I would also have to keep track of the season and time of the day to ensure that the insects that help in transferring pollen are likely to be around and whether I have enough nutrients and water to make plans.

6:19 U: Right. That's our second step. Integrating or combining all the cues to instruct the plant to develop flowers. Here's Professor Lodha again.

6:29 L: So now there are too many cues. So how do they decide? So there is a process of integration. What integration actually means is that all these cues are regulating a small set of genes? So this small set of genes can take you from all other external or internal cues like hormones, temperature. And then actually there is the second step which will tell, ok, that now all the cues seem like that we should flower.

6:57 U: But integrating is not as easy as it sounds. You see, all the cues are usually selected by leaves. How will that information reach the stem?

7:15 A: Messengers are involved, maybe.

7:12 U: You're on the right track, Anushka. There is a messenger called Flowering Locus T which is produced in the leaves. Through the transport system of the plant, it reaches the shoot where there are a lot of undifferentiated cells, that is cells that haven't yet specialized to become a leaf stem or a flower. When flowering locus T comes to them, some cells together form floral primordial or the initial flower.

7:45 H: Fascinating. This reminds me of the human messengers from old times.

7:51 U: Yes, exactly. Like the human messengers Hamsini, these messengers help to take the information from the leaves to the stem. Now, guess what the final step is? A: Flowering U: It was obvious, wasn't it?

8:21 L: So now after the second step, they give cue to the third step of flowering were really the flower organ formation genes starts to express that specific tissue. And then luckily they help in flower formation.

8:33 A: Flowers are really good. Who knew there were so many complex processes going on internally in the very flower that I was observing.

8:39 H: Now, I'm curious to know how flowering mechanisms are studied in the lab.

8:44 J: Hm. Good question, Hamsini. Let's go back and talk to Professor Mukesh Lodha.
…and now it's time to ask a scientist.

8:59 J: Thank you so much, Professor Lodha, for telling us all about how flowers bloom. Could you please also tell us what you do as a plant scientist?

9:05 L: So my name is Mukesh Loha and I'm a faculty at Center for Cellular and Molecular Biology. So I studied plant sciences from my BSc. BSc in Botany, MSc in Botany. Then I actually did research on plants. So in my PhD, I studied the Chlamydomonas reinhardtii, which is a unicellular green alga. And for my postdoc career, I studied Arabidopsis thaliana, which is a mustard family plant. And in my lab here at CCMB, we study development, for example, flowering and leaf development. And we specifically look for the processes which are governed by epigenetics. So I will quickly tell you what epigenetics is. So in genetics, we know that DNA is the key thing. DNA sequence determines the character and DNA sequence actually inherited from parents to the next generation. But in case of epigenetics, the inheritance is there, but it is not encoded in the form of DNA sequences. So there are other things, for example, histones which are proteins which wrap DNA, there are RNAs, which are also inherited from one generation to another generation. So we are specifically interested in epigenetic regulation of plant development. And one of our key interests is flowering, specifically flowering time.

10:34 J: Epigenetics sounds super cool, Prof Lodha. It's interesting to know that there is more than just DNA involved in hereditary processes. How do you study epigenetics in your lab? I wonder.

10:46 L: So our life actually is divided into, let us say two parts. So one part actually is the facility where we grow plants. So there are plant growth chambers. And there are rooms where we mainly control the temperature and light cycle. So usually plants are either short day plants or long day plants. So there is a control of light, the timing of light, the cycle of light and dark and temperature. So these two things we can maintain and this is a little bit apart from our main lab. So what we do is to grow plants there, we study flowering time there. For example, when the plant flowers, we just put a plant there that day to get flowers. So these things we do in the power of other parts of the lab. And then actually DNA RNA analysis, we usually bring the plants in the lab, we crush them to isolate DNA or RNA or proteins. And then it's a regular molecular biology lab where there is equipment to isolate DNA, RNA. We do chemical reactions in the tubes and we have all sorts of fancy equipment to analyze our DNA RNA.

12:02 J: Could you please also tell us about how you analyze the DNA and RNA?

12:06 L: Then actually one method we use a lot is electrophoresis. So what is electrophoresis? Electrophoresis is separation by charge. So some of the molecules which you isolate DNA RNA protein, have electric charge on them. Very small amount. Not like the current in our home, but a very small amount of charge. And as we know, if you, they will go to the opposite charge. So there are chambers where there are two opposite types of charges, positive and negative. And these molecules are kept in between by different ways and they're separate according to the charge. If something is positively charged, it will go towards the negative pole and vice versa. So this helps initially separation of molecules basically. So this is the one method we call electrophoresis. So usually on electrophoresis, you can separate DNA RNA and proteins, so all three molecules and then there are actually other equipment which I will tell you a little bit about. So one of the equipment is called PCR- a thermal cycler. So what this machine is, this machine has a small metal block and this metal block can change temperature according to our need. So there is a computerized program inside. So you can program it to remain at 95 degrees for 30 seconds. Then let us say 58 degrees for 30 seconds and then at 72 for one minute, for example. So what does it help? So this machine is mainly used for making more copies of DNA. So in test tubes, you can add everything that is needed to make more copies of DNA. You can put it in this machine. So what this machine does is to help in different steps of the DNA application or DNA amplification, you can say, and this way you can make many copies of a DNA of your interest. So this is called Polymeric Chain Reaction.

14:02 J: That's very interesting. But moving on a bit to how your journey has been as a plant researcher and studying epigenetics of flowering plants. I would like to understand how to develop this passion towards this topic. Did you always know that you were going to be a scientist one day or was this something that happened over time? And how did you realize that you were passionate about the topic?

14:35 L: It happened over time actually as a child, I didn't know. Actually, I grew up in a very, very small place. Actually, this was a village of 5000 people. And then when I grew up, there was not much communication, there was no TV, no radio, no telephone. So we were not informed. We did not know the world. So the career choices and everything came along with time actually. And for plants, I also keep thinking about why this plant work came to me. And I think what happened is that my father had a small garden. So he used to grow and specifically, he used to grow flowers, actually, not so much of other things. And I think from there actually, somewhere in my mind was that this is the thing to do and this is the thing to work with. I think that helped me to go towards plants.

15:25 J: It's really inspiring to know that you grew up in a small town. I wonder what message you would like to give to our budding scientists who would like to choose a career in science, just like you.

15:40 L: You see, every person is a different person and I'm not against becoming an engineer or doctor. Actually, my brother is a physician. That's totally fine. The thing is that whatever you do in the study. Very good. You try your best. And keeping your mind open towards everything. Curiosity is really important. It's important that you think about why winds move? Why white light above give light? What is the mechanism in the car that it moves or how is the brake used? So all these things, you keep asking yourself and asking your colleagues and parents and teachers. So that is important. And there's for students like you, there should be no pressure to become something right? You are what you are and try to learn what you are supposed to learn. And along the way you will find your passion that's very clear. There's no hurry to find, find the passion right now.

16:40 A: So what did we learn today?

16:42 J: We learned that blooming of flowers serves an important function for the plant. It helps the plant to make seeds, which keeps the species alive. We also learned that the plant has to integrate the internal and external cues to understand what is the right time to bloom. It sends out a messenger to its tip to initiate the flowering process.

17:06 U: Exactly. And we also learned from Dr Lodha that epigenetic mechanisms can also regulate the blooming of flowers. These are hereditary processes apart from our DNA blueprint.

J: He also inspired us with his journey of becoming a scientist. He says, whatever you do, do your best and always ask questions. But listeners, what we know about flowers blooming and its reasons might change as we get more evidence over time.

17:46 U: Who knows, one of our listeners might discover new processes of flowers blooming in the future and find out something about them that we never knew before.

U: That’s it for today. If you enjoyed listening to our episodes, make sure to visit our website, www.indiaaskswhy.org, for more content. You’ll find illustrations, transcripts, blogs, and scientist profiles for all our episodes!

J: We’re sure we must have sparked your curiosity. You can submit all your questions on our website and get a chance to be featured in one of our episodes.

U: Follow us on Instagram and Twitter for more updates. Link in Show Notes.

J: IndiaAsksWhy is funded by IndiaBioscience Extension Grant.

U: Shweata N. Hegde and Ruchi Manglunia are the hosts of the podcast

J: Shweata N. Hegde audio-edited the episode, and Khushi Goel transcribed it.

U: Also, thanks to all our team members for enabling Utsuka and Jigyasa to chase their curiosity!

J: Special thanks to Anushka and Hamsini for joining us, and a big shout to Delhi Public School, Secunderabad teachers for making this possible.

U: Finally, a big shout-out and thanks to Prof. Mukesh Lodha for answering all the curious questions we posed!

J: Don’t forget to like and rate our podcast to keep the new content coming to you at all times! Until then, stay tuned and stay curious!