Survivability of seeds in the universe

In space, seeds exposed to many ultraviolet rays and cosmic radiation can cause their germination ability to decrease.

To accomplish our goal of flying into space and settling down on another planet, we need to address many major challenges, including sustaining ourselves for a long time when we have to leave Earth, according to Earth Sky. Therefore, scientists need to consider the possibility of growing food supply plants, instead of relying on reserve food carrying the spacecraft.

The team placed seeds outside the International Space Station (ISS) to understand the impact of the cosmic environment on them.(Photo: NASA).

However, the environment is much harsher than the Earth. Seeds must be able to withstand a large amount of ultraviolet and cosmic radiation, low pressure and microgravity.

David Tepfer and Sydney Leach, two French cosmologists, said the seeds have some noteworthy characteristics that help them protect themselves in space.First , the seed contains many copies of important genes, also known as backup genes . If a gene copy is broken, there are still other genes that do the job. Second , the seed coat contains flavonoids that act as sunscreens, protecting the seed's DNA from being damaged by ultraviolet (UV) light.

To find out whether these characteristics are sufficient to help the seeds survive the cosmic environment, Tepfer and Leach conducted a series of experiments outside the International Space Station (ISS) and on Earth for seeds. varieties of tobacco and arabidopsis plants. Their experiment began in 2008 and lasted 558 days. The results of the study are published in Astrobiology magazine in March 2017.

The team stored seeds outside ISS in a special glass layer, allowing UV light to shine at a wavelength of 110 to 400 nm. DNA can absorb ultraviolet rays in this wavelength range easily. A group of identical identical seeds are completely shielded from UV rays on the ISS. Tepfer and Leach chose the seeds of tobacco and arabidopsis plants for experiments because they both carry a backup set of genes so they have a better survival rate.

When the seeds returned to Earth, the team measured the germination rate as well as the rate of root growth from the seed coat. Results showed that the seeds shielded in space had a germination rate of more than 60%. The seeds in direct contact with UV rays have a 3% germination rate.

Seeds shielded in space have a germination rate of more than 60%.

Of the 11 germinated Arabidopsis plants, including wild and transgenic species, none survived when grown on the ground. Tobacco plants grow more slowly than normal, but growth rates recover in later generations. Tobacco plants have larger reserve genes, so there are many obvious advantages.

This discovery promises to open new directions in the field of space agriculture. Future studies need to learn more about how seeds germinate in conditions of gravity much smaller than Earth.