Scientists put moss on the skin of the International Space Station for 9 months — then saved it rising again on Earth

Moss spores have survived a protracted journey to house, scientists reveal. The spores spent 9 months on the skin of the International Space Station (ISS) earlier than returning to our planet, and over 80% of the spores have been nonetheless capable of reproduce after they arrived again on Earth.

The discovery improves our understanding of how plant species survive in excessive circumstances, the researchers wrote of their findings, printed Thursday (Nov. 20) within the journal iScience.

Moss thrives in some of the most extreme environments on Earth, from the cold peaks of the Himalayas to the dry, scorched sands of Death Valley. Moss’s resilience to adverse conditions makes it an ideal candidate for surviving in the harsh environment of outer space, where extreme temperature fluctuations, altered gravity, and high radiation exposure push life-forms to their limits.

Previous experiments have explored how plants might cope in space, but so far, they have focused on larger organisms resembling micro organism or plant crops. Now, researchers have proven that samples of the moss Physcomitrium patens (P. Patens) cannot solely survive however thrive in house.

First, the researchers examined three cell sorts of P. patens from numerous levels within the moss’s reproductive cycle. They discovered that sporophytes — cell constructions that encase spores — confirmed the best stress tolerance when uncovered to ultraviolet (UV) mild, freezing and warmth.

Sporophyte samples have been then positioned exterior of the ISS in a particular exposure facility hooked up to Japan’s Kibo module, the place the samples lived for round 9 months in 2022. After this time, the samples have been returned to Earth.

“Surprisingly, over 80% of the spores survived and many germinated normally,” research lead writer Tomomichi Fujita, a professor of plant biology at Hokkaido University in Japan, instructed Live Science in an electronic mail. From this research, Fujita and his workforce developed a mannequin that implies the moss spores might really survive for as much as 5,600 days in house, or round 15 years.

Back on Earth, the workforce discovered that many of the circumstances — together with the vacuum of house, microgravity and excessive temperature fluctuations — had a restricted influence on the moss spores. However, samples that have been uncovered to mild, notably high-energy wavelengths of UV mild, fared much less nicely. Levels of pigments utilized by the moss for photosynthesis, resembling chlorophyll a, have been considerably lowered on account of mild harm, which affected later moss progress.

Even although some moss samples confronted harm from the circumstances of outer house, P. patens nonetheless fared significantly better than different plant species which have been beforehand examined beneath related circumstances. Fujita thinks the protecting, spongy casing surrounding the spores could assist defend towards UV mild and dehydration.

“This protective role may have evolved early in land plant history to help mosses colonize terrestrial habitats,” he mentioned.

While this may occasionally appear to be an train in testing the bounds of a single species, the “spores’ success in space could offer a biological stepping stone for building ecosystems beyond our planet,” Fujita mentioned. In the longer term, he hopes to check different species and higher perceive how these resilient cells survive such annoying circumstances.