Rob Ferl, left, and Anna-Lisa Paul looking at the plates filled part with
lunar soil and part with control soils, now under LED growing lights. At the
time, the scientists did not know if the seeds would even germinate in lunar
soil. Credits: UF/IFAS photo by Tyler Jones
NASA-funded study breaks new ground in plant research
In the early days of the space age, the Apollo astronauts
took part in a visionary plan: Bring samples of the lunar surface material,
known as regolith, back to Earth where they could be studied with
state-of-the-art equipment and saved for future research not yet imagined.
Fifty years later, at the dawn of the Artemis era and the next astronaut return
to the Moon, three of those samples have been used to successfully grow plants.
For the first time ever, researchers have grown the hardy and well-studied
Arabidopsis thaliana in the nutrient-poor lunar regolith.
Anna-Lisa Paul, left, and Rob Ferl, working with the lunar soils in their lab. Credits: UF/IFAS photo by Tyler Jones
“This research is critical to NASA’s long-term human exploration goals as we’ll need to use resources found on the Moon and Mars to develop food sources for future astronauts living and operating in deep space,” said NASA Administrator Bill Nelson. “This fundamental plant growth research is also a key example of how NASA is working to unlock agricultural innovations that could help us understand how plants might overcome stressful conditions in food-scarce areas here on Earth.”
Scientists at the University of Florida
have made a breakthrough discovery — decades in the making — that could
both enable space exploration and benefit humanity. “Here we are, 50 years
later, completing experiments that were started back in the Apollo labs,” said
Robert Ferl, a professor in the Horticultural Sciences department at the
University of Florida, Gainesville, and a communicating author on a paper
published on May 12, 2022, in Communications Biology. “We first asked the
question of whether plants can grow in regolith. And second, how might that one
day help humans have an extended stay on the Moon.”
The answer to the first question is a
resounding yes. Plants can grow in lunar regolith. They were not as robust as
plants grown in Earth soil, or even as those in the control group grown in a
lunar simulant made from volcanic ash, but they did indeed grow. And by
studying how the plants responded in the lunar samples, the team hopes to go on
to answer the second question as well, paving the way for future astronauts to
someday grow more nutrient-rich plants on the Moon and thrive in deep space.
To
Boldly Go, We Must Boldly Grow
“To explore further and to learn about the
solar system we live in, we need to take advantage of what’s on the Moon, so we
don’t have to take all of it with us,” said Jacob Bleacher, the Chief
Exploration Scientist supporting NASA’s Artemis program at NASA Headquarters in
Washington. Bleacher points out that this is also why NASA is sending robotic
missions to the Moon’s South Pole where it’s believed there may be water that
can be used by future astronauts. “What’s more, growing plants is the kind of
thing we’ll study when we go. So, these studies on the ground lay the path to
expand that research by the next humans on the Moon.”
Arabidopsis
thaliana, native to Eurasia and Africa, is a
relative of mustard greens and other cruciferous vegetables like broccoli,
cauliflower, and Brussels sprouts. It also plays a key role for scientists: due
to its small size and ease of growth, it is one of the most studied plants in
the world, used as a model organism for research into all areas of plant
biology. As such, scientists already know what its genes look like, how it
behaves in different circumstances, even how it grows in space.
Working with Teaspoon-sized
Samples
Placing a plant grown during the experiment in a vial for eventual genetic analysis. Credits: UF/IFAS photo by Tyler Jones
To grow the Arabidopsis,
the team used samples collected on the Apollo 11, 12, and 17 missions, with
only a gram of regolith allotted for each plant. The team added water and then
seeds to the samples. They then put the trays into terrarium boxes in a clean
room. A nutrient solution was added daily.
“After two days, they started to sprout!”
said Anna-Lisa Paul, who is also a professor in Horticultural Sciences at the
University of Florida, and who is first author on the paper. “Everything
sprouted. I can’t tell you how astonished we were! Every plant – whether in a
lunar sample or in a control – looked the same up until about day six.”
Anna-Lisa
Paul tries moistening the lunar soils with a pipette. The scientists found that
the soils repelled water (were hydrophobic), causing the water to bead-up on
the surface. Active stirring of the material with water was required to break
the hydrophobicity and uniformly wet the soil. Once moistened, the lunar soils
could be wetted by capillary action for plant culture. Credits: UF/IFAS
photo by Tyler Jones
After day six,
however, it was clear that the plants were not as robust as the control group
plants growing in volcanic ash, and the plants were growing differently
depending on which type of sample they were in. The plants grew more slowly and
had stunted roots; additionally, some had stunted leaves and sported reddish
pigmentation.
After 20 days, just before the plants
started to flower, the team harvested the plants, ground them up, and studied
the RNA. In a biological system, genes are decoded in multiple steps. First,
the genes, or DNA, are transcribed into RNA. Then the RNA is translated
into a protein sequence. These proteins are responsible for carrying out
many of the biological processes in a living organism. Sequencing the RNA
revealed the patterns of genes that were expressed, which showed that the
plants were indeed under stress and had reacted the way researchers have seen Arabidopsis respond
to growth in other harsh environments, such as when soil has too much salt or
heavy metals.
By
day 16, there were clear physical differences between plants grown in the
volcanic ash lunar simulant, left, compared with those grown in the lunar soil,
right. Credits: UF/IFAS photo by Tyler Jones
Additionally, the plants reacted
differently depending on which sample – each collected from different areas on
the Moon – was used. Plants grown in the Apollo 11 samples were not as robust
as the other two sets. Nonetheless, the plants did grow.
Sowing
the Seeds for Future Research
This research opens the door not only to
someday growing plants in habitats on the Moon, but to a wide range of
additional questions. Can understanding which genes plants need to adjust to
growing in regolith help us understand how to reduce the stressful nature of
lunar soil? Are materials from different areas of the Moon more conducive to
growing plants than others? Could studying lunar regolith help us understand
more about the Mars regolith and potentially growing plants in that material as
well? All of these are questions that the team hopes to study next, in support
of the future astronauts traveling to the Moon.
“Not only is it pleasing for us to have
plants around us, especially as we venture to new destinations in space, but
they could provide supplemental nutrition to our diets and enable future human
exploration,” said Sharmila Bhattacharya, program scientist with NASA’s
Biological and Physical Sciences (BPS) Division. “Plants are what enable us to
be explorers.”
This research is part of the Apollo Next
Generation Sample Analysis Program, or ANGSA, an effort to study the samples returned
from the Apollo Program in advance of the upcoming Artemis missions to the Moon’s South Pole. BPS helped
support this work, which also supports other fundamental plant research,
including Veggie, PONDS, and Advanced Plant Habitat.
About BPS
NASA’s Biological and Physical Sciences Division pioneers scientific discovery
and enables exploration by using space environments to conduct investigations not
possible on Earth. Studying biological and physical phenomenon under
extreme conditions allows researchers to advance the fundamental
scientific knowledge required to go farther and stay longer in space, while
also benefitting life on Earth.
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Source: Scientists Grow Plants in Lunar Soil
| NASA
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