Desert Moss Could Hold the Key to Growing Plants on Mars – ExtremeTech

Close-up of S. caninervis. Credit: John Game/Wikimedia Commons

At first glance, Syntrichia caninervis looks like a dust bunny or a gray, low-lying shrub. But this humble moss is known for surviving harsh conditions that most plants find uninhabitable, like the aridity of Antarctica and the Mojave Desert. Inspired by the plant's resilience, researchers have pushed S. caninervis to its limits and found that it can endure extreme cold, drought, and high levels of radiationthe conditions a plant would need to withstand to grow food on Mars.

In a paper published Monday in the scientific journal The Innovation, researchers at the Chinese Academy of Sciences (CAS) write that S. caninervis is a "promising pioneer plant for colonizing extraterrestrial environments." The moss is considered extremotolerant, a term frequently applied to tardigrades to testify to their near-invincibility. While most mosses require shade and abundant moisture to flourish, S. caninervis does things differently. It's evolved to withstand 98% water loss, conduct photosynthesis while covered with snow, and survive extremely low and extremely high temperatures, placing it "among the most stress tolerant organisms."

It just so happens that researchers have spent the last decade or so eagerly searching for ways to grow plants in space. Whether by sowing seeds in lunar soil or farming inside a simulative Mars habitat, everyone from NASA and the European Space Agency to educational institutions and Elon Musk wants to make extraterrestrial agriculture happen. It can't be overstated that this is a tough thing to succeed at; while we know Mars and the Moon don't offer the nurturing conditions we enjoy here on Earth, finding (or producing) the right plant for the job is another task entirely.

But what about reverse-engineering a Mars-worthy plant? Recognizing how uniquely rugged S. caninervis can be, the arid ecology experts at CAS decided to see how much strain the moss could survive. First, they obtained S. caninervis samples, some of which were left fully hydrated while others were intentionally dehydrated. The researchers placed samples from both groups in a freezer at -80 degrees Celsius (-112 Fahrenheit) for three to five years, in a liquid nitrogen storage tank at -196 Celsius (-320 Fahrenheit) for 15 to 30 days, and 500 to 16,000 grays of gamma radiation. Then, they transferred the samples to a sandbox subjected to Mars-like pressures, gases, and UV radiation.

Credit: Li et al, The Innovation/DOI 10.1016/j.xinn.2024.100657

Samples from all three exposure groups (freezer, nitrogen storage, and gamma radiation) successfully generated new branches. While some groups thrived more easily than othersdehydrated plants had an easier time recovering than plants that started out fully hydratedS. caninervis proved capable of bouncing back after enduring extremely low temperatures and levels of radiation similar to those they'd experience on Mars. The researchers also noted that an extra two years of exposure to cold temperatures didn't significantly affect S. caninervis regeneration.

Make no mistake: Like most mosses, S. caninervis isn't tasty and wouldn't make it onto a Martian menu. But, as the CAS researchers point out, S. caninervis could drive efforts to genetically engineer edible plants resistant to the Red Planet's harsh environment. The moss also appears to be a "promising candidate" in contributing to oxygen production, carbon sequestration, and soil fertility on extraterrestrial landsthree pieces of the long-term Mars colonization puzzle.

"Although there is still a long way to go to create self-sufficient habitats on other planets, we demonstrated the great potential of S. caninervis, a model moss plant, as a pioneer plant for growth on Mars," the researchers write. "Looking to the future, we expect that this promising moss could be brought to Mars or the Moon to further test the possibility of plant colonization and growth in outer space."

The rest is here:

Desert Moss Could Hold the Key to Growing Plants on Mars - ExtremeTech