Effects of Mars Global Simulant (MGS-1) on Growth and Physiology of Sweet Potato: A Space Model Plant

Abstract

Growing food autonomously on Mars is challenging due to the Martian soil's low nutrient content and high salinity. Understanding how plants adapt and evaluating their nutritional attributes are pivotal for sustained Mars missions. This research delves into the regeneration, stress tolerance, and dietary metrics of sweet potato (Ipomoea batatas) across different Mars Global Simulant (MGS-1) concentrations (0, 25, 50, and 75%). In our greenhouse experiment, 75% MGS-1 concentration significantly inhibited sweet potato growth, storage root biomass, and chlorophyll content. This concentration also elevated the plant tissues' H₂O₂, proline, and ascorbic acid levels. Higher MGS-1 exposures (50 and 75%) notably boosted the vital amino acids and sugar groups in the plant's storage roots. However, increased MGS-1 concentrations notably diminished the total C:N ratio and elemental composition in both the vines and storage roots. In summary, sweet potato exhibited optimal growth, antioxidant properties, yield, and nutrient profiles at 25% MGS-1 exposure as compared to higher concentrations. This study underscores the need for future interventions, like nutrient enhancements and controlled metal accessibility, to render sweet potato a suitable plant for space-based studies.

Keywords: Mars Global Simulant; amino acids; antioxidant; proline; stress tolerance; sugar classes.

Figure 1

Effects of the different concentrations of MGS-1 exposure on (A) total chlorophyll and (B) proline of I. batatas leaves. Results are expressed as means of replicate ± SE, where ‘*’ indicates statistical significance (p < 0.05), ‘**’ indicates statistical significance (p < 0.01), and ‘***’ indicates statistical significance (p < 0.001) according to Tukey’s test.

Figure 2

(A) Effects of various concentrations of MGS-1 exposure on H₂O₂ accumulation in I. batatas leaves, and (B) microscopic images of H₂O₂ accumulation. (i) control, (ii) 25%, (iii) 50%, and (iv) 75% of MGS-1 exposure.

Figure 3

Amino acid profiling of storage root tissues grown under control and different levels of MGS-1 exposure. (A) PLS-DA score plot, (B) VIP plot, (C) correlation plot analysis, and (D) hierarchical cluster analysis.

Figure 4

Effects of the different concentrations of MGS-1 exposure on the elemental accumulation in the vines and storage roots of I. batatas plants (A) Al, (B) B, (C) Fe, (D) K, (E) Mg, (F) Mn, (G) Na, (H) P, (I) Si, and (J) Zn. Results are expressed as means of replicate ± SE, where ‘*’ indicates statistical significance (p < 0.05), ‘**’ indicates statistical significance (p < 0.01), and ‘***’ indicates statistical significance (p < 0.001) according to Tukey’s test.