Martian soil contains the right stuff for growing rice

Dirt on Mars may have all the necessary nutrients for growing rice, planetary scientist Abhilash Ramachandran reported March 13 at the Lunar and Planetary Science Conference. But the plant may need a bit of help to survive amid perchlorate, a chemical that has been detected on Mars’ surface and can be toxic to plants.

“We want to send humans to Mars … but we cannot take everything there. It’s going to be expensive,” says Ramachandran, of the University of Arkansas in Fayetteville. Growing rice there would be ideal, because it’s easy to prepare, he says. “You just peel off the husk and start boiling.”

Ramachandran and colleagues grew rice plants in a Martian soil simulant made of Mojave Desert basalt. They also grew rice in pure potting mix, as well as several mixtures of the potting mix and soil simulant.

Rice plants grew in the synthetic Mars dirt but developed shorter, thinner shoots and wispier roots than the plants that sprouted from the potting mix or hybrid soils. Even replacing just 25 percent of the simulant with potting mix helped heaps, the team found.

The researchers also tried growing rice in soil with added perchlorate. They sourced one wild rice variety and two cultivars genetically modified for resilience against environmental stressors like drought and grew rice in Mars-like dirt with and without perchlorate.

No rice plants grew amid a concentration of 3 grams of perchlorate per kilogram of soil. But when the concentration was just 1 gram per kilogram, a seed from one of the modified lines grew both a shoot and a root, while a seed from the wild variety managed to grow a root.

By tinkering with the successful rice’s modified gene, SnRK1a, humans might be able to develop a rice cultivar suitable for Mars.

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