by More than 50 years after astronauts brought the last lunar rock samples back to Earth, scientists have successfully grown plants in lunar soil from three Apollo missions for the first time.
Everyone MoonSoil plants grew slowly and relatively poorly, but those grown in samples that had been most exposed on the lunar surface tended to be the worst, and genetic analysis showed changes indicative of stress. The meager growth could be a cause for concern: As NASA prepares to send astronauts back to the moon via its sagebrush program, and eventually even to Mars, being able to grow food on alien soil during long missions will become increasingly important.
“The ability to successfully take plants with us to the moon is… how we will grow our own food.” [and] how we’re going to stay there for a while without resupply,” Robert Ferl, a professor of horticultural sciences at the University of Florida and an author of the study, said at a virtual news conference on Wednesday (May 11). He also noted that growing plants in The moon could have other potential uses, including air purification, removal of carbon dioxide exhaled by humans, and production of clean water.
Related: NASA Fed Moon Rocks From Apollo 11 To Cockroaches (And Then Things Got Even Weirder)
For this study, the researchers used samples of lunar soil, called regolith, taken during Apollo 11, 12 and 17between 1969 and 1972. In all three samples, they grew a common laboratory specimen, a small plant called thale cress (Arabidopsis thaliana). For comparison, the scientists also grew thale cress in a type of soil made from volcanic ash found on Earth, called JSC-1A by NASA, meant to simulate lunar soil, which is dusty and littered with debris. abrasive glass.
“The fragments are actually quite sharp and angular,” Stephen Elardo, a University of Florida geologist and study author, said at the news conference. Lunar soil also contains bits of metallic iron, and glass fragments trap pockets of gases, which are not fully replicated by volcanic ash.
The researchers were able to cultivate Arabidopsis in all three samples. The plants did worse in the Apollo 11 soil, which was the most “mature,” meaning the soil had been most exposed to the lunar surface. (Because the moon lacks a protective atmosphere like land‘s, its surface is hit by meteorites, the fragments of atoms that scientists call cosmics rays and the constant stream of charged particles coming out of the sun). The plants grew better in the Apollo 12 sample, which was less mature, and in the Apollo 17 sample, which was the least mature.
All of the plants that grew in the lab-made volcanic ash grew noticeably faster and larger than any found in lunar soils.
Furthermore, a genetic analysis of the plants revealed that, compared to plants grown in volcanic ash, those grown in lunar soil expressed many genes related to salt, oxidative stress, and associated with metals.
Apollo 11 plants expressed changes in 465 genes, while Apollo 12 plants expressed 265 genes at different rates, and Apollo 17 plants 113. Most of these changes were stress-related. When they grouped the plants by appearance, they found that the worst-looking plants (small and reddish-black) also had the most genetic changes associated with stress.
The results suggest that soil that is more exposed to the lunar surface is worse for plants, which may be due to changes caused by exposure to cosmic rays and the solar wind, the researchers wrote. If this is true, the researchers argued, soil from the youngest parts of the moon could be more effective at growing healthy plants. Although even the healthiest of these plants would be stunted and slow growing, the food they produce would not necessarily be harmful and could still be nutritious. In fact, many types of produce with dark pigmentation, such as blueberries and blueberries, are valued for their antioxidants produced in response to oxidative stress.
Eating plants grown on lunar soil like this likely “poses no threat to humans,” Anna-Lisa Paul, a horticultural scientist at the University of Florida, said at the news conference. “It’s hard to say, but it’s more likely that the chemicals that plants produce in response to stress also help human stress.” She said future research would be needed to explore how lunar soil might affect the nutritional value and quality of foods grown on this soil.
It’s also clear from this research, the scientists said, that simulated lunar soil is not an effective substitute for the real thing in an experiment like this, despite some similarities. Growing plants in lunar soil permanently changes their chemistry, so an experiment like this has never been done before with the “precious natural treasures” that are the Apollo samples, Paul said. But the exact chemistry of lunar soil is unique and can provide scientists with insights that simulated soil never could.
“The devil is in the details,” Elardo said. “And the plants are concerned with the details.”
the investigation was published May 12 in the journal Communications Biology.
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