Plants on the Moon
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Plants can grow in lunar soil. Though it’s not the ideal environment since the plants become stressed and brittle, plants can still germinate in soil derived from the moon, grow roots, sprout leaves, and even potentially become edible.
Research funded by the National Aeronautics and Space Administration (NASA) and conducted by a team of researchers at the University of Florida was published on May 12 in the journal “Nature Communications Biology.” The research was conducted in support of the Artemis Program, which plans to send humans to the Moon once again. The mission requires a better understanding of biological responses to the Moon’s soil, known as lunar regolith, which is fundamentally different from Earth’s soil: it is the habitat of limited organic elements, high radiation levels, and volcanic glass. Earlier lunar explorations have established that lunar soil samples did not harbor pathogens that may harm terrestrial life. However, the plants in the earlier experiments were only dusted with lunar regolith—they were never actually grown in it.
The May 2022 study was written and conducted by Anna-Lisa Paul, a University of Florida plant molecular biologist, and Robert Ferl, a distinguished professor of horticultural sciences at the UF Institute of Food and Agricultural Sciences. Though questions regarding lunar fertility have revolved for years, scientists have only recently received the opportunity to grow plants in lunar soil. The process would irreversibly alter the chemistry of the soil, hence permanently contaminating “precious natural treasures.” In spite of this, after the scientists applied for the opportunity to work with lunar regolith three times over the course of 11 years, NASA granted Paul and Ferl a loan of 12 grams of lunar soil, collected during the Apollo 11, 12, and 17 missions to the Moon between 1969 and 1972.
The small amount of soil provided meant that Paul and Ferl had to conduct a small-scale, carefully conducted experiment. Therefore, the team created a tiny lunar garden with thimble-sized wells functioning as pots for each trial plant to grow in, placed in small plastic plates that are normally used to culture cells' grammar. After they filled each well with nearly one gram of lunar soil, the scientists moistened the soil with a nutrient solution and added seeds from the Arabidopsis thaliana plant, hoping to harvest the thale cress weed. The Arabidopsis plant was chosen for experimentation because its fully mapped genetic code would allow the researchers more insight into the genetic effects that the soil would have on the plants. As a control in the experiment, the researchers also planted Arabidopsis seeds in soil harvested from extreme environments on Earth, such as volcanic ash and JSC-1A, a terrestrial substance that resembles lunar regolith.
Astoundingly, all the plants looked the same up until day six. Afterward, the lunar sample mediums appeared less robust in comparison to the controls and began showing signs of stunted roots along with reddish pigmentation that made the normally green weeds appear violet. After 20 days, all of the seeds sprouted. The plants were then harvested and their DNA was studied.
The genetic reports of the plants revealed similarities to plants grown in hostile environments, specifically environments that contained high concentrations of heavy metals. These findings were reasonable due to the high “glass fragment” findings in lunar regolith; lunar regolith is powdery and fine-grained, which makes the soil sharp-edged and abrasive. Nonetheless, though the plants’ growth indicated high stress levels, the plants still found a way to germinate fairly quickly, especially given the nutrient deficiency in lunar soil and with little aid from light, nutrients, and water. Paul claims the next step in the team’s research is to use the data derived from the analysis of the Arabidopsis’ gene expression to address methods with which they can enhance the plants’ biological stress responses. They hope that genetic modifications may induce a level of fitness in the plants that will allow them to grow in the lunar soil in a way that is not detrimental to their health.
NASA’s Artemis program aims to place astronauts on the southern pole of the Moon by 2025. With NASA preparing to send astronauts back to the Moon for the first time since 1972, being able to take advantage of natural resources found directly on the Moon has become increasingly important. Essentially, plant growth in lunar soil is a crucial step toward establishing lunar colonies, or long-term habitats on the Moon.
While there is no oxygen or carbon dioxide in the Moon’s atmosphere, plants could potentially alter lunar soil in a similar manner to which they have altered soil on Earth. If scientists manage to discover the precise reason for the growth defects in the plants grown in lunar mediums, they may be able to target genes that can counteract the environmental stresses and successfully harvest crops on the Moon. Once the modified plants are suitable for growth on the Moon, they can convert waste carbon dioxide exhaled by astronauts into oxygen, transforming the Moon’s atmosphere into a more breathable one, providing nutritional benefits to the astronauts who are there long-term.
With today’s technology, humans would have little difficulty merely reaching the Moon, but with long-term aspirations in mind like the building of a lunar base that would allow habitual human activity on the Moon, it has remained nearly impossible for a crew to take all the materials they would need with them. Therefore, it only makes sense to use the resources already available on the Moon, and because of these recent developments, lunar regolith may soon be added to the charter.