Barley seeds were exposed to outer space for 13 months in a vented metal container without a climate control system to assess the risk of physiological and genetic mutation during long-term storage in space. The space-stored seeds (S0 generation), with an 82% germination rate in 50 seeds, lost about 20% of their weight after the exposure. The germinated seeds showed normal growth, heading, and ripening. The harvested seeds (S1 generation) also germinated and reproduced (S2 generation) as did the ground-stored seeds. The culm length, ear length, number of seed, grain weight, and fertility of the plants from the space-stored seeds were not significantly different from those of the ground-stored seeds in each of the S0 and S1 generation. Furthermore, the S1 and S2 space-stored seeds respectively showed similar β-glucan content to those of the ground-stored seeds. Amplified fragment length polymorphism analysis with 16 primer combinations showed no specific fragment that appears or disappears significantly in the DNA isolated from the barley grown from the space-stored seeds. Though these data are derived from nine S0 space-stored seeds in a single exposure experiment, the results demonstrate the preservation of barley seeds in outer space for 13 months without phenotypic or genotypic changes and with healthy and vigorous growth in space.
Research Containing: Barley
The gene expression and enzyme activity of superoxide dismutase, catalase, and ascorbate peroxidase in the space-grown barley were not significantly different from those of the ground-grown barley. Cu2+ reducing and radical scavenging activities in an extract of the space-grown barley were lower than those of the ground-grown barley by 0.7 fold, suggesting that the space environment does not induce oxidative stress, and reduces antioxidant capacity in plants.