Nasa scientists grew corn seeds in space and found that microgravity changed how the seedlings’ roots and shoots grew
Long before astronauts ever plant a seed on the Moon or Mars, Nasa has been testing a much simpler question here on Earth’s doorstep: what happens when a corn seed germinates with no gravity to tell it which way to grow? Back in the early 1990s, researchers flew dry corn kernels aboard the space shuttle, let them sprout in orbit, and compared them against identical seedlings grown under normal gravity on the ground. The plants survived. Their tissue looked healthy. But something was clearly missing. Without gravity acting as a compass, the roots and shoots lost their sense of direction entirely, growing in tangled, unpredictable patterns instead of the neat, downward and upward paths seen on Earth. The findings showed that plants could still develop in space, but their normal growth patterns depended heavily on gravity. This raised important questions about how future crops might be cultivated during long-duration missions, where reliable food production could become essential for astronauts. It is a small but telling result, and one that Nasa has kept building on ever since, through experiments on corn and a range of other plants aboard the International Space Station.
What happened to corn seeds in space without gravity
One of the clearest examples comes from a Nasa-funded shuttle experiment described in a 1992 paper archived on the agency’s Technical Reports Server, hosted by Nasa’s Kennedy Space Centre. Researchers imbibed dry corn kernels, launched them into orbit, and allowed them to germinate and grow for five days in darkness, comparing the seedlings against identical batches grown under normal gravity on Earth.According to Nasathe shuttle-grown seedlings developed largely as expected in terms of weight, hormone levels, and tissue structure, but with one striking exception. As per the researchers, the tissues of the shuttle-grown plants appeared normal, and the seedlings differed only in the lack of orientation of roots and shoots. In other words, the plants grew perfectly healthy tissue; they simply could not tell which way to point it.
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How does gravity guide plant growth
On Earth, gravity gives a germinating seed an unambiguous cue: roots grow down, shoots grow up. Remove that cue, and a seedling has to rely on other signals, such as light, moisture gradients, or its own internal mechanical sensing, to decide which direction to grow. The corn experiment showed that when gravity disappears, roots and shoots stop following a single consistent path and instead grow in a jumble of directions, an effect popularly described as roots and shoots losing their orientation, or growing in twisted, disorganised patterns rather than the straight lines seen on Earth.Crucially, the Nasa researchers were cautious about over-interpreting a five-day snapshot. As per the paper, the findings could not be extrapolated to growth in microgravity for weeks, months, and years, of the kind that might be needed aboard a future space station or transit vehicle to Mars. The seedlings looked healthy over five days; nobody yet knew what would happen over five months.
Do other plants also lose direction in space
Corn is far from the only species to show this kind of directional confusion in orbit. Nasa-funded experiments using Arabidopsis thaliana, a small mustard-family plant that is the workhorse of plant spaceflight biology, have repeatedly documented roots that “skew” or curve away from a straight growth path once gravity is removed. According to a 2020 study published in Frontiers, titled ‘Root Skewing-Associated Genes Impact the Spaceflight Response of Arabidopsis thaliana’, in Plant Science and conducted aboard the International Space Station, this skewing behaviour was long assumed to require gravity as a reference point, and the observation that it persists in orbit overturned that assumption.A separate Nasa-supported ISS experiment, known as CARA, reached a similar conclusion from a different angle: gene activity rather than visible shape. As per the 2024 paper published in Nature, titled ‘Light has a principal role in the Arabidopsis transcriptomic response to the spaceflight environment’, plant tissue grown on the space station showed distinctive patterns of gene switching depending on whether it was exposed to light or kept in darkness, reflecting a complex, tissue-specific effort by the plant to reorganise its own growth machinery in the absence of gravity. Taken together with the corn results, the pattern across species is consistent: plants do not fail in microgravity, but they do lose their built-in compass.
How is Nasa preparing to grow food in space
The agency has built an entire open-access infrastructure specifically to capture and share findings like these. The Open Science Data Repository serves as a one-stop location for a variety of the agency’s space biological data, consolidating decades of plant, animal, and human spaceflight research from Nasa’s Ames Life Sciences Data Archive and GeneLab databases into a single searchable system.That matters because Nasa’s plans for long-duration missions, including eventual crewed trips to Mars, assume astronauts will be able to grow at least part of their own food along the way. Understanding exactly how and why plants lose their sense of direction in microgravity, while still growing healthy tissue as the corn experiment showed, is a necessary step towards designing growth systems, lighting cues, or even genetic tweaks that can compensate for the missing gravity signal before crews ever depend on space-grown crops for survival.
