Scientists grow plants in lunar soil for the first time
Image credit: Tyler Jones/UF/IFAS
Plants have been grown in soil from the Moon for the first time – a milestone that means humans may one day be able to grow plants for food and oxygen on the Moon during space missions.
In the new study, researchers from the University of Florida showed the arabidopsis plant – thale cress – can successfully sprout and grow in soil that was collected from the Apollo 11, 12, and 17 missions.
The study also investigated how plants respond biologically to the Moon’s soil, also known as lunar regolith, which is very different from soil found on Earth.
“Showing that plants will grow in the lunar soil is actually a huge step in that direction of being able to establish ourselves in lunar colonies,” said Rob Ferl, a professor of horticultural sciences at the UF Institute of Food and Agricultural Sciences (UF/IFAS).
Ferl stressed it was important to show both that lunar soils were not harmful to terrestrial life and that terrestrial life could establish itself.
The researchers also established what the findings mean in relation to growing food fit for human consumption on the Moon.
Anna-Lisa Paul, a research professor of horticultural sciences in UF/IFAS, explained: “The plants that were responding the most strongly to what we would call oxidative stress responses, those are the ones, especially in the Apollo 11 samples, that turned purple.
“And that’s the same thing that’s in blueberries and cranberries, and all of those dark red and purple fruits that are healthy for humans because of their anti-oxidative properties.
“We definitely don’t know the nutritive value of these plants, but it is likely not to pose any threat to humans. It’s hard to say, but it’s more likely that the chemicals that plants produce in response to stresses are ones that also help human stresses as well.
“So it’s likely to be a more benign or helpful response than the other way around.”
Dr Paul added that while arabidopsis is edible, it is not tasty. “It belongs to the same family as mustard, cauliflower, and broccoli, so many of the things learned could translate into the same metabolic strategies and processes that our good friend broccoli uses.”
The researchers set about planting seeds in lunar soil, adding water, nutrients, and light, and analysing the growth and results. But because of the rare nature of the samples, the scientists had just 12 grams of soil to work with.
The upcoming Artemis mission will require a better understanding of how to grow plants in space, and so the experiment became more immediately relevant.
The researchers used thimble-sized wells in plastic plates normally used to culture cells, and once each was filled with roughly one gram of lunar soil, they moistened it with a nutrient solution and added a few seeds from the arabidopsis plant.
In order to conduct comparisons, they also planted seeds in the soil from Earth that mimics real lunar soil, as well as simulated Martian soils and terrestrial soils from extreme environments.
The researchers found that all the seeds planted in the lunar soils sprouted.
However, they stressed that just because the plants all grew, this does not mean they did so as normal. Some of those grown in the lunar soils were smaller, were different colours, grew more slowly, or were more varied in size than their counterparts.
According to the scientists, how plants respond to lunar soil may be linked to where the soil was collected. For instance, the researchers found that the plants with the most signs of stress were those grown in what lunar geologists call mature lunar soil.
“It’s really good news that plants can grow in the lunar soils,” said Dr Ferl. “This presents to lunar colonists, to lunar scientists, a bunch more options than if they simply failed to grow there.”
He added: “But the bottom line is that until it was actually done, nobody knew whether plants, especially plant roots, could interact with the very sharp antagonistic soils the lunar regolith presents.”
Earlier this month, researchers at Nanjing University in China said soil on the Moon can be converted into carbon dioxide, oxygen, and fuels that could be used to help support the greater exploration of its surface.
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