© Tomomichi Fujita, Hokkaido University; press image for Maeng et al.: Extreme environmental tolerance and space survivability of the moss, Physcomitrium patens. iScience, 2025, supplemental material / CC BY-SA (detail)

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This plant even survives the hostile universe

26.11.2025

Translation: machine translated

Without protection, it's quickly over for us in space. Tardigrades and mosses, on the other hand, are tougher. This was shown by an experiment on the ISS.

Tardigrades are considered the most resilient animals in the world. They survive dehydration, freezing and the high-energy radiation of space without damage. And now there is good news for them: Their favourite home could also survive the journey through the cosmos unscathed, as mosses can also cope with a stay outside the protective shell of a spaceship, as an experiment by Chang-hyun Maeng from the University of Hokkaido in Sapporo proves.

Together with his team, the biologist tested which components of the moss (Physcomitrium patens), such as the protonemata - filamentous pre-germs of the moss -, brood cells or spore capsules, are best able to withstand adverse conditions. It has already been shown that the spore capsules can withstand heat, cold, freezing or vacuum in larger numbers. They therefore travelled to the International Space Station (ISS) as test objects, where they then spent nine months orbiting the Earth on the outside of the ISS, virtually unprotected. During this time, they were exposed to the extreme cold, dryness and radiation of space. After their return to Earth, they were then placed on culture media.

To the researchers' great surprise, 80 per cent of the spore capsules tested germinated and grew into living mosses. Maeng and co had assumed that practically all spore capsules would not survive the harsh conditions. At least at this cellular level, some plants can survive under very extreme conditions and have protective mechanisms against harsh radiation or cold.

Looking at the evolutionary history of mosses, this resilience is perhaps not all that surprising: after all, they are considered to be the first plants to have conquered the land 500 million years ago, where they paved the way for higher plants. The only real measurable consequence of the excursion into the cosmos was a reduced proportion of chlorophyll a, a green pigment that is essential for photosynthesis. Its content in the mosses after rearing was 20 per cent lower than in conspecifics that had not left the earth. In contrast, other forms of chlorophyll were not affected, meaning that the overall photosynthetic performance of the plants was barely impaired.

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Original article on Spektrum.de

Header image: © Tomomichi Fujita, Hokkaido University; press image for Maeng et al.: Extreme environmental tolerance and space survivability of the moss, Physcomitrium patens. iScience, 2025, supplemental material / CC BY-SA (detail)

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