Lettuce grown in space on the International Space Station (ISS) has been well-received by astronauts, but researchers believe it may not be as healthy as previously thought.
Astronauts onboard the International Space Station utilize a system called Veggie to add water and nutrients to plants, enabling them to grow their own leafy greens, including red leaf lettuce. However, recent findings suggest that lettuce cultivated in a simulated microgravity environment on Earth may be more prone to infections such as E coli or Salmonella than lettuce grown in space, possibly posing a risk to astronauts’ health. A paper published in Scientific Reports detailed how a team of researchers utilized a device known as a clinostat to rotate plants, disrupting their sense of directionality. Noah Totsline, the lead author of the paper, explained that this caused the plants to lose their normal response to gravity, as they could no longer distinguish up from down. The plants’ natural defense mechanisms became less effective in a microgravity setting, leading to unexpected outcomes such as the opening of stomata in the presence of bacteria, making it easier for bacteria like Salmonella to penetrate the leaf tissue. As a result, the level of bacteria in the space-grown lettuce exceeded that of Earth-grown lettuce, raising concerns about the safety of these greens consumed by astronauts living in the closed-air environment of the ISS. Despite efforts to address the challenges posed by microgravity, the potential impact of pathogens on the Veggie system, which serves as a vital food source for future space missions to the Moon or Mars, remains a concern. In response, researchers are exploring genetic modifications to space lettuce to reduce the risk of bacterial infections by preventing wider stomata opening in space. They are also conducting tests on various lettuce varieties in simulated microgravity environments to assess their suitability for cultivation in space.
