They grow plants successfully on the soil of the Moon

Arabidopsis plants six days after planting the seeds. The four wells on the left contain plants growing on the JSC-1A lunar soil simulator. The three pits on the right contain plants growing in lunar soil collected during the Apollo 11, 12, and 17 missions. / UF/IFAS by Tyler Jones

Science | Horticulture

It is a novelty in human history and a milestone in lunar and space exploration.

The Little Prince grew a rose on an asteroid and now it seems that we will also have a beautiful garden on the Moon. For the first time in history, scientists from the University of Florida (UF) have successfully grown plants in the soil of our satellite, also known as lunar regolith, an environment radically different from the terrain of Earth whose fertility has surprised researchers .

Rob Ferl and Anna-Lisa Paul, lead authors of the paper and distinguished professors of horticultural sciences at the UF Institute of Food and Agricultural Sciences, knew that NASA had lunar soil that was collected during the Apollo 11, 12 and 17 missions and they wanted to use it to investigate, but it was not easy to get it. After making three requests over the course of 11 years, the US space agency gave its arm to twist and granted them 12 grams of lunar regolith (approximately 3-4 teaspoons), a minimum amount that, together with the incalculable historical and scientific importance of the sample, forced scientists to design a carefully choreographed experiment on a small scale so as not to fail.

His little lunar garden had thimble-sized 'pots' set in plastic plates normally used to grow cells. Each 'pot' contained approximately one gram of lunar soil, which the scientists moistened with a nutrient solution and added some seeds of the Arabidopsis plant.

The advantage of this plant species, and the reason it was selected for the study, is that its genetic code has been fully mapped, so the researchers were able to see how the lunar regolith affected the plants' DNA.

First shoots and differences

For comparison, the researchers also planted Arabidopsis in JSC-1A, a terrestrial substance that mimics real lunar soil, as well as simulated Martian soils and terrestrial soils in extreme environments.

A few days later, the first shoots appeared. "We weren't sure if seeds planted in lunar soils would sprout. But almost all of them did, so we were amazed. That confirmed for us that lunar soils do not disrupt the signals involved in plant germination," Paul said. "We wanted to do this experiment because, for years, we asked ourselves this question: Would plants grow on lunar soil? The answer, it turns out, is yes," added Ferl.

But the plants grown in lunar regolith showed differences with those of the control group. For example, some were smaller, grew more slowly, or were more varied in size, all physical signs that plants were working and adapting to cope with the chemical and structural composition of the Moon's soil. And this was even more evident when the researchers analyzed the gene expression patterns of the plants.

"At the genetic level, the plants were putting out the tools they normally use to cope with stressors, such as salt, metals or oxidative stress, so we can infer that they perceive the lunar soil environment as stressful," he said. Paul. So one of his goals now is to use this data to develop solutions that allow lunar crops to grow without stress and with very little impact on their health.

mature lunar soil

According to the researchers, the characteristic plant response to lunar soil may be related to where the regolith was collected. Thus, the researchers discovered that the plants with the most signs of stress were those that grew in what lunar geologists call mature lunar soil, which are the ones that are most exposed to the cosmic wind, which alters its composition. For their part, plants grown in less mature soils fared better.

“The Moon is a very, very dry place. How will the minerals in the lunar soil respond to having a plant growing on them, with the added water and nutrients? Will adding water make the mineralogy more hospitable to plants? These are questions posed by UF assistant professor of geology Stephen Elardo, who has also collaborated on the research. Follow-up studies will help answer them.

Through the UF Space Plants Laboratory, Paul and Ferl, who are internationally recognized experts in the study of plants in space, have sent space shuttle experiments to the
International Space Station and in suborbital flights. This work is a first step towards growing plants that will one day serve as a source of food and oxygen on the Moon, or during other space missions, making it a milestone in space exploration. And it occurs at a key moment, as NASA's Artemis Program plans to return humans to the Moon in the coming years.