Testing New Concepts for Crop Cultivation in Space: Effects of Rooting Volume and Nitrogen Availability

Abstract

Long term human missions to the Moon and Mars, rely on life support systems for food production and regeneration of resources. In the EU H2020 TIME SCALE-project, an advanced life support system concept was developed to facilitate plant research and technology demonstration under different gravity conditions. Ground experiments assessed irrigation systems and effects of rooting- and nutrient solution volume. The maximal allowed volume for existing International Space Station research facilities (3.4 L) was able to support cultivation of two lettuce heads for at least 24 days. A smaller rooting volume (0.6 L) increased root biomass after 24 days, but induced a 5% reduction in total biomass at day 35. Regulating effects of nitrate supply on plant water fluxes in light and dark were also investigated. At low concentrations of nitrate in the nutrient solution, both transpiration and stomatal conductance increased rapidly with increasing nitrate concentration. During day-time this increase levelled off at high concentrations, while during nigh-time there was a distinct decline at supra optimal concentrations. Plants supplied with nitrate concentrations as low as 1.25 mM did not show visible signs of nutrient stress or growth reduction. These findings hold promise for both reducing the environmental impact of terrestrial horticulture and avoiding nutrient stress in small scale closed cultivation systems for space.

Rocket Science: The Effect of Spaceflight on Germination Physiology, Ageing, and Transcriptome of Eruca sativa Seeds

“…Rocket species, including E. sativa, are commercially important salad crops cultivated worldwide [76]. It is therefore an important plant for nutrition and food (fresh produce) during spaceflights [12,13,[15][16][17]. Colla et al (2007) demonstrated that rocket seed germination and seedling growth on board the ISS was affected in that the maximum germination percentage was reduced from 95% to 80% and that subsequent seedling growth and nutrient content were negatively affected.…”

“…Molecular analysis of growing seedlings and adult plants in microgravity by epigenomics [10], transcriptomics, and proteomics [8,9,11] identified known and novel genes specific for the response to the space environment. This research has potential to be applied to growing fresh food derived from plants for nutrition and human survival in space during long-distance space travel [5,7,[12][13][14][15][16][17]. These works demonstrated that successful 'seed-to-seed' plant cultivation and propagation is possible but also that space-produced seeds may differ in reserve composition and properties.…”

Plant Gravitropism and Signal Conversion under a Stress Environment of Altered Gravity

“…In another study, the in vitro cell culture of Arabidopsis thaliana was placed under different conditions of simulated microgravity, at Mars gravity (0.38 g) and hypergravity (2 g), to study the cell proliferation, growth and appearance [ 8 , 58 ]. The most relevant changes occurred in the 24-h treatment, which was more pronounced for simulated gravity decline than for supergravity, which indicated that changes in gravity effects include severe interference with cell proliferation and growth [ 58 ]. The key transcripts responded to altered gravity have been identified.…”

Water and Microbial Monitoring Technologies towards the Near Future Space Exploration

“…Beside the on-demand crew consumption, on-board waters are distributed for different purposes, comprising hygiene and cleaning practices, urinal flushing, oxygen generation via electrolysis, life-support systems, and flexible water-based experimental activities (e.g., vegetable and food production systems, animal physiology and behavioral adaptation tests) (Baiocco et al, 2018;Chatani et al, 2015;Massa et al, 2016;Niederwieser et al, 2018;Ronca et al, 2019;Wolff et al, 2018). Wastewaters are continuously collected and recycled at high efficiency level.…”