Space ​Cucumbers Help ​Us Engineer More ​Drought-​tolerant Crops

Published on by in Technology

Space ​Cucumbers Help ​Us Engineer More ​Drought-​tolerant Crops

Cucumber seeds grown on board the International Space Station show an unusually strong tendency to grow towards water. This finding might help us engineer more drought-tolerant crops suitable for cultivation on Earth.

By Lakshmi Supriya

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Watering time for the space cucumbers JAXA and NASA

Plant growth is strongly influenced by the environment: stems grow up towards the sun, while roots grow down under the influence of gravity – an effect called gravitropism.

But in space, Earth’s gravitational pull is much less pronounced. Back in 1998, Hideyuki Takahashi of Tohoku University, Japan, began investigating how plant roots behave in these unusual conditions. Through an experiment on the space shuttle Discovery, his team accidently discovered that roots bend if they grow in microgravity.

Takahashi and his colleagues wondered whether the roots were bending in response to small variations in the humidity of their environment and so showing a “hydrotropic” response – growing towards water rather than with gravity. “The hypothesis is, in microgravity, the hydrotropic response will become pronounced,” he says.

To investigate further, the researchers sent cucumber seeds into space aboard the space shuttles Atlantis and Discovery in 2010. Japanese and US astronauts performed a series of experiments on the International Space Station, and the seedlings came back to Earth in 2011.

Onboard the ISS, the seeds were grown in a small chamber with wet filter paper on one side to set up a moisture gradient. Some of the seeds were allowed to grow in the ISS’s microgravity environment, others were grown inside a centrifuge to simulate Earth’s gravity.

The cucumber roots grown in microgravity bent towards the wet substrate, sometimes by as much as 60 degrees from the vertical. Those in conditions simulating Earth’s gravity grew vertically “downwards”.

Unexpectedly, the plant hormones – auxins – that encourage cucumber roots to grow downwards on Earth also seemed to encourage them to grow towards water in space. This suggests cucumber roots have a hidden ability to seek out water – but the power is masked on Earth because of their stronger response to gravity.

Read full article: New Scientist

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