Abstract EANA2024-66

By the end of this decade, NASA plans to return to the Moon, and, most importantly, establish a permanent settlement there within the Artemis space program [1]. Such an ambitious initiative brings many challenges, one of them being the necessity to secure food supplies to the astronauts participating in these near-future lunar missions.

Vascular plants have been considered an integral part of remote and long-term space missions, particularly as a source of fresh food for crews. In combination with the so-called in situ resource utilization (ISRU), an idea of using as much of the original on site resources as possible, the concept of cultivation of crops directly in the „lunar soil“ arises [2]. In the past, studies investigating the ability of plants to grow in the lunar regolith have been carried out [3,4]. These experiments have been mostly conducted on regolith simulants, however in 2022, a study on Arabidopsis thaliana grown in an actual lunar regolith sample obtained during the Apollo missions was published [5]. These works showed, that plants can grow in these substrates, although significant stress responses have been observed.

The main focus of our experiment has been to evaluate the effects of cultivation of selected plant species in lunar regolith on photosynthesis using the method of in vivo induced chlorophyll fluorescence. Moreover, we have compared the results gained for a synthetically prepared lunar regolith simulant (source: National Technical University of Athens, Greece), to those obtained for a volcanic rock-related regolith collected on the James Ross Island, Antarctica. Both regolith samples  were sieved in order to obtain a fraction of particles below 2 mm that were used for chemical analysis.  Atomic absorption spectrometry and other analytical methods were used to evaluate the differences in elemental content between the two regolith samples.  In this way, we evaluated the potential of the antarctic regolith in future astrobiological plant studies.

From the regolith samples, we have prepared a) water extract in distilled water and b) acidic extract using a weak acetic acid. They were used as solutions for germination test of selected vascular plant species. In follow-up experiment, the extracts were used as cultivation media. Nutrients have then been added to the media, and the same nutritive medium has been used as control. The plants then have been grown from the seed in these regolith extracts in special-designed minichambers composed of  microbiological plates and a cover transparent for light.  During cultivation,  controlled environment (photosynthetically active radiation, air temperature) was maintained in the minichambers. After germination of the seeds and formation of the first leaves, we measured time courses of several chlorophyll fluorescence parameters in order to evaluate regolith effect of plant vitality, primary photosynthesis in particular. For that purpose, maximum quantum efficiency of photosystem II (FV/FM), the quantum yield (ΦPSII), and non-photochemical quenching (NPQ) were measured in approximately 1 week interval.

 

 

 

 

 

 

 

 

 

 

 

 

References:

[1] M. Smith et al., "The Artemis Program: An Overview of NASA's Activities to Return Humans to the Moon", 2020 IEEE Aerospace Conference, 2020

[2] L. G. Duri et al., "The Potential for Lunar and Martian Regolith Simulants to Sustain Plant Growth: A Multidisciplinary Overview", Frontiers in Astronomy and Space Sciences, 2022

[3] D. G Mortley et at., "Growth of Sweetpotato in Lunar and Mars Simulants". SAE Technical Paper 2000-01– 2289. Warrendale, PA: SAE International, 2000

[4] G. W. W Wamelink et al., "Can Plants Grow on Mars and the Moon: A Growth Experiment on Mars and Moon Soil Simulants", PLOS ONE, 2014

[5] A. Paul, S. M. Elardo, R. Ferl, "Plants Grown in Apollo Lunar Regolith Present Stress-Associated Transcriptomes That Inform Prospects for Lunar Exploration", Communications Biology, 2022