Seeds in the kitchen, seeds in the forest, but ever heard of seeds in space? Yes, you heard it right. In fact, seeds were the first living organisms to be sent to space. The answers to your when, how, why, await you in this story from Satyashree, a seed scientist by profession.
Keen to explore more? Binge hear our collection of ‘Seed Stories’ here:
Good evening everyone! This is Aasif and you are listening to Hello Educator.
Today’s episode is from Mango Science Radio and it is from a seed scientist Satyashree. This episode is about seeds in space.
00:35 Hi! You’re listening to Satyashree. I think you remember me. We were speaking so much about seeds and I know we feel a connect, but I think at this point we need some space. Yes, not personal space but the vast big glorious space, the majestic universe which makes us feel like nothing. Today, let’s speak something about space, but not just space, seeds in space. I know, I’m stuck hard with these seeds and that makes me revolve around it.
01:15 So, wondering whether seeds have been sent to space? Yes, and of course, seeds were the first living organisms to be sent to space, even before Laika the dog. If you were taught in schools as Laika to be the first living organism to be sent to space, correct it. Laika was the first animal to be sent to space. Laika was sent to space in 1957 whereas many seeds were sent to space even before that. That is, in 1946 in a V2 rocket launched by NASA.
01:56 Seeds, as we were speaking for days, are living things. So the first living space traveller was the seed. Yes, the seed. Why should seeds be sent to space? If you believe in life on the moon or Mars then you need seeds to grow your food and survive there, isn’t it? That’s the reason scientists sent seeds to space to learn about the effect of radiation on seeds.
02:27 Since the first V2 rocket studies, the scientific community has learned a great deal about the effect of the space environment on seed germination, metabolism, genetics, biochemistry and even seed production. Recently, agrobiologists named David Tepfer and Sydney Leach investigated how seeds would do, back on Earth, after spending extended periods on the International Space Station. They called this Mission ‘the expose mission’. Why? Because they exposed the seeds to space, they called this mission the expose mission.
03:08 In the experiment, they placed the seeds outside of the International Space Station, that is, the dead of space. The goal was to understand not only the effects of long-term radiation exposure but a bit about the molecular mechanisms of those effects. It was first expected that seeds can’t survive the radiations and the scientist predicted that radiation might lead to damage in the genome leading to reduced viability or functionality in seeds. But surprisingly, the seeds survived and more than 60 per cent of these seeds showed normal germination back on Earth.
03:56 How come these tiny seeds survived those intense radiations? When scientists were wondering, Tepfer and Leach came up with two hypotheses.
The first one was that the seeds contain multiple copies of important genes, what they called scientifically as genetic redundancy. Genetic redundancy is nothing but the same phenomenon as we take photocopies of some important documents. Why do we take photocopies? If the original document is missed we can make use of the photocopies. The same happens in seeds. In some organisms, some important genes have multiple copies, so if one copy is damaged, the other copy can rescue the function. The same was found in flowering plants, especially in all the food products producing plants like watermelon, strawberries and many others. So the seed produced from this plant also had genetic redundancy, and that’s what was making the seeds overcome genetic damage.
This was the first hypothesis proposed by Tepfer and Leach about how the seeds are overcoming the genetic damage. If you wonder about the mechanism, Google about ‘DNA repair mechanisms using site-specific recombinases’. You will find wonders there!
05:24 The second hypothesis they proposed was related to our superheroes. Who are they? None other than our seed coats. Wondering how? On Earth, we know our atmosphere filters out harmful UV radiations, but in space, there is no filter. You can imagine the damage it might cause, and the effects would be similar to the consequences of the ozone depletion, but even more intense. But thanks to the seed coat, the superhero which contains chemicals called flavonoids that act as sunscreens. I think you all wear sunscreen when you go out to play in the summer. Have you ever wondered what is there in the sunscreen?
06:12 The sunscreen contains flavonoids, either synthetic or plant-based flavonoids in it and the seeds in the seed coat also contain these flavonoids which have proven UV filtering capacity. Tepfer and Leach proposed that these flavonoids in seed coats might play a role in seed survival in space, preventing UV radiation damage.
06:39 These were the two hypotheses proposed by Tepfer and Leach, but as it is said- what can be asserted without evidence can be dismissed without evidence. We need proof in science or it will just stay as a belief. Thus, Tepfer and Leach also tested their hypotheses. Wondering about the results? Soon we will discuss the results and also the effects of gravity on seed germination. Until that, keep wondering.
We sincerely hope that you really liked this episode. We upload one science story every day and if you are a science enthusiast and you would like to contribute to Mango Science Radio, please WhatsApp us at 9952243541 and you can also share your feedback via an audio message or Whatsapp. That would really be helpful. Thank you again, thank you so much for listening to Hello Educator. I will see you tomorrow.
Music by Karthikeyan KC