The plant that grows best after a dose of radiation can help Terraform Mars

Researchers have identified a plant that can survive harsh conditions on Mars, potentially helping future humans to form it.

If humans ever want to make a home elsewhere in the Solar System, Mars seems like the most viable bet, beating out the competition by not being a hell world, having a surface we can actually stand on, and being at the edge of the zone. habitable where liquid water can exist.

But a lot would have to be done to transform the planet into one we could call home. In short, along with many other home comforts, higher temperatures and a kind of breathable atmosphere would be nice.

Growing plants on the planet, which would convert some of the planet’s 95 percent carbon dioxide atmosphere into breathable oxygen, would be a useful start. In a new paper, a team from the Chinese Academy of Sciences put a plant to the test; a type of moss called Syntrichia caninervis, it is most commonly found in the biological soil crust (BSC) of colder deserts.

“Among land plants, mosses are often the pioneer species naturally selected for growth in extreme environments. The moss crust represents an advanced stage in the development of BSCs,” the team wrote in their paper. “Compared to algal and lichen crusts, moss crusts have greater biomass and carbon fixation capacity, thus playing important roles in biogeochemical cycles and stabilizing the desert surface.”

The species is particularly suited to extreme environmental stressors, including drought, cold and radiation, making the moss a good candidate for surviving Martian conditions. The team tested this by subjecting the moss to similar conditions in the laboratory, starting with subjecting the plants to extreme dehydration. The moss survived the dehydration and resumed physiological activities “within seconds of rehydration.”

The hydrated and dehydrated plants were then subjected to extreme cold. Plants were placed in a −80°C (−112°F) freezer for 3 or 5 years and in a −196°C (−321°F) liquid nitrogen storage tank for 15 or 30 days before were transferred to sterilized sand. for healing. The team found that the plants recovered surprisingly well after being subjected to these extreme conditions, with dehydrated plants doing slightly better than their dehydrated counterparts.

“After 15 and 30 days of storage in liquid nitrogen, plants ultimately regenerated approximately two new branches,” the team wrote, “the rate of regeneration was approximately 95 percent that of control plants.”

The team then subjected the plants to the kind of extreme radiation they would face on the red planet, exposing hydrated and dehydrated plants to between 500 and 16,000 grays (Gy) of radiation. Again, the plants tolerated the conditions surprisingly well, at least at lower doses. When the radiation was between 500 and 1000 Gy, the plants actually recovered better than the control plants.

However, when subjected to higher doses, plants took longer to recover. Above 4000 Gy caused the plants to show signs of stress and after 60 days of recovery, these plants had a regeneration rate of 70 percent. Again, dehydrated plants fared better, although the team found that the dose at which 50 percent of the organisms survived was about a one-hour treatment of 5,000 Gy.

That’s a lot of radiation, showing how hardy the plants are. Humans will generally suffer severe convulsions and/or death around 50 Gy, while plants can generally withstand no more than about 1000 Gy.

Finally, using the Planetary Atmospheres Simulation Facility at the Chinese Academy of Sciences, the team placed the plants in Mars-like conditions, including the balance of gases in the Martian atmosphere and temperature fluctuations similar to those seen on the planet. for 1, 2, 3. , and 7 days. Dehydrated plants recovered 100 percent after a 30-day recovery time, while hydrated plants—which were subjected to only one day in the facility—regenerated, but more slowly than dehydrated plants.

“Although there is still a long way to go to create self-sustaining habitats on other planets, we demonstrated the great potential of S. caninervisa model moss plant as a pioneer plant for growing on Mars,” the team concluded. “Looking to the future, we expect this promising moss to be brought to Mars or the Moon to further test the possibility of colonization and plant growth . in outer space”.

The paper was published in The Innovation magazine.