The last manned flight to the moon was in 1972 as part of Apollo 17. NASA’s Artemis program is set to finally bring humans back to the near-Earth celestial body in the 2020s. A lunar base is planned and annual manned landings. An important question is whether the living conditions on the Earth’s satellite can be improved through planting.
To test whether the lunar soil can support plant life, University of Florida researchers Anna-Lisa Paul, Stephen Elardo, and Robert Ferl grew specimens of thale cress (Arabidopsis thaliana) in 12 extraterrestrial soil samples and published the results in the journal Nature Communications Biology «. The samples were from the Apollo 11, 12 and 17 lunar missions and consisted of regolith. Regolithic material is a mixture of crushed rock and solidified molten rock. The researchers investigated whether the growth and gene expression of these seedlings differed from those grown in 16 samples of volcanic ash from Earth. The ash is similar in particle size and mineral composition to lunar soil.
© Tyler Jones, UF/IFAS (detail)
laboratory work | Anna-Lisa Paul (left) and Rob Ferl work with the lunar soils in their laboratory.
The team showed that growth was challenging for the seedlings: the lunar regolith plants were slow to develop and had more stunted roots than specimens grown in volcanic ash. They also expressed genes that indicate ionic stress – similar to how plants respond to salt, metals and reactive oxygen species. Some contained reddish-black pigments – traits that also indicate plant stress. Ferl and his colleagues suggest that the effects of cosmic rays and solar wind on the lunar soil, as well as the presence of small iron particles, trigger stress responses in plants and impair their development.