If humans ever make it to Mars, they may bring a little color along with them. As Katherine Kornei reports for Science, a new study suggests that the seeds of the morning glory flower can withstand radiation levels that would fry other types of seeds.
Back in 2008, the space shuttle Atlantis carried an experiment to the International Space Station called EXPOSE-E—a module full of biological samples including organic molecules, microoraganisms, as well as lichens and fungi. The module also included 2,000 seeds from two plants: tobacco and Arabidopsis thaliana, a weedy European plant used often in research. The samples were secured outside the confines of the space station for 558 days, exposed to extreme temperatures, UV light and cosmic radiation. Astronauts then collected them and returned them to terra firma.
Not surprisingly, most of the seeds fried—but 20 percent germinated and grew into "normal-looking plants," writes Kornei.
Almost a decade later, researchers decided to look at the seeds that didn’t germinate to figure out why. Analyzing an antibiotic resistance gene in the tobacco plants, the researchers determined that DNA degradation from short wave UV radiation deactivated the seeds by causing some parts of the genetic code to fuse, reports Kornei.
Though the researchers were interested in learning more, sending seeds into space is costly. So they recreated the conditions of space in the lab. According to the study published recently in the journal Astrobiology, they exposed more tobacco and Arabidopsis seeds to UV radiation. But they also included morning glory seeds, which are comparatively large and have been known to last for decades in the soil. While most of the tobacco and Arabidopsis seeds lost their ability to germinate after exposure to some 87 megajoules per square meter of radiation, all of the morning glories survived. They could withstand radiation up to a massive dose of 2420 megajoules.
It’s likely that the heavy seed coat of the morning glory protected it, and Kornei reports that the researchers believe flavonoids—compounds found in wine and tea—in the seed might also act as a cosmic sunscreen. The research means that properly protected seeds could survive on trips to Mars and bolsters the idea of “panspermia” or the hypothesis that life can spread from planet to planet by traveling on comets or asteroids.
The seeds are “model space travelers,” the researchers write in the paper. Much of their genome is redundant, which means they have multiple copies of genetic information if some of it gets damaged. Seeds are also designed to survive long stretches of cold with no water and carry bacteria and fungi that could hitch a ride to a new planet. And even if a seed doesn’t survive a long journey through space, it still brings organic materials like proteins, nucleic acids and ribosomes to wherever it lands, which could help jumpstart primitive forms of life.
“These results add to the fast-growing body of evidence showing that panspermia is not only possible, but absolutely inevitable,” Chandra Wickramasinghe, director of the Buckingham Centre for Astrobiology at the University of Buckingham, tells Kornei.
Whether or not morning glories spread throughout the galaxy, it’s likely researchers will continue to send seeds into space. Scientists first attempted a seed launch in the 1940s, when they put added seeds to the capsules of V2 rockets, reports Kelsey Campbell-Dollaghan at Gizmodo. In 1983, the Park Seed company launched 40 different fruit and vegetable seeds into space as part of special collaboration with NASA. (They later launched seeds that they sold for a hefty $27 per packet.)
Cherry trees joined in the fun on another seed launch into space in 2008. Four of those trees bloomed in 2014, much more quickly than the ten years common for the plant.
But there is much more to be learned from the space faring seeds. And discoveries from the glorious morning glory could lead the way.