Space Agriculture and Astrobiology
Bioremediation of lunar regolith simulant through mycorrhizal fungi and plant symbioses enables chickpea to seed
Chickpea plants partnered with mycorrhizal fungi and vermicompost can grow and produce viable seeds in lunar regolith simulant, offering a promising biological strategy for sustainable food production on the Moon.
Imagine you tried to grow vegetables in crushed-up volcanic glass mixed with toxic dust — that's basically what Moon dirt (called regolith) is like. It has sharp, jagged particles, almost no nutrients, and contains chemicals that stress plants out. Scientists wanted to see if they could make Moon dirt farmable. They mixed it with worm poop (vermicompost), which adds nutrients, and introduced a special fungus that lives on plant roots and helps them absorb water and nutrients. The plant they chose was the chickpea — a hardy, protein-rich legume. The result? When the fungus was present, chickpea plants actually grew flowers and made seeds even in soil that was 75% Moon dirt. Without the fungus, no seeds at all. The fungus also helped the Moon dirt clump into small balls, which makes it less dusty and dangerous. Think of it like the fungus being a personal trainer and nutritionist for the plant, helping it survive and thrive where it normally couldn't.
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Chickpea plants inoculated with Arbuscular Mycorrhizal Fungi (AMF) successfully produced seeds in lunar regolith simulant (LRS)/vermicompost mixtures containing up to 75% LRS, while non-inoculated plants failed to set seed in any LRS mixture.
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AMF inoculation extended plant survival in 100% LRS by approximately two weeks compared to non-inoculated plants, with senescence delayed from day 61 to day 75.
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AMF colonized roots across all LRS/VC mixtures including 100% LRS, demonstrating the capacity to establish symbioses under extreme regolith conditions.
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Although increasing LRS concentration reduced total seed count, standardized seed mass (100-seed weight) remained comparable to controls in LRS50 and LRS75, indicating that seed quality was maintained even as yield declined.
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AMF and vermicompost improved the structural properties of LRS by promoting aggregate formation, potentially mitigating hazardous particle-related properties of lunar regolith.
Food sustainability is a significant challenge for long-term space travel. Plants can provide fresh nutrition, reducing reliance on packaged foods. Using Lunar regolith simulant (LRS), we tested a methodology to create a productive growth medium for horticultural crops on the Moon. We leveraged chickpea (Cicer arietinum), Arbuscular Mycorrhizal Fungi (AMF), and Vermicompost (VC) to enhance plant stress tolerance, sequester contaminants, and improve substrate structure. Chickpeas were cultivated in LRS/VC mixtures, with or without AMF, under climate-controlled conditions. Plants seeded successfully in mixtures containing up to 75% LRS when inoculated with AMF. While the number of seeds declined with increasing LRS concentration, seed size remained stable. Higher LRS concentrations induced stress; however, plants grown in 100% LRS inoculated with AMF demonstrated an average extension of two weeks in survival compared to non-inoculated plants. AMF colonized roots across all mixtures, including 100% LRS, demonstrating the ability to establish symbioses under extreme conditions. We also observed improvement in the structural properties of LRS by forming aggregates capable of withstanding extreme conditions, potentially mitigating particle-related hazards. These results provide a baseline for chickpea establishment and yield in amended LRS while demonstrating biological improvements in regolith properties.