China is to launch a satellite that will carry plant seeds into space then return them to Earth for sowing. The idea is that radiation exposure in space will induce genetic mutations in the seeds, some of which could have beneficial effects.
But US researchers who have experimented on seeds in space say there is not enough of a benefit to justify the cost. Instead they see the launch as a publicity ploy.
Chinese researchers have previously reported sowing over 600,000 hectares of land with space-exposed seeds, and have claimed remarkable results. For example, they say pimiento trees grown from such seeds produce more pimientos that taste sweeter, have more vitamins, are more resistant to disease and have a longer shelf life.
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They have also sent rice, cotton, oil seeds, fruits and vegetables into space. But none of this research has appeared in scientific journals where it could be reviewed by other scientists.
鈥淚 think maybe the benefits were overly described,鈥� says Weijia Zhou, director of the Wisconsin Center for Space Automation and Robotics, who was the lead scientist on plant and seed experiments that flew 10 times on the space shuttle, once on the Russian station Mir and three times on the International Space Station.
Endurance test
China鈥檚 seed satellite would fly seeds 200 to 400 kilometres above Earth, according to the official news agency Xinhua. After being exposed to space for some time, part of the spacecraft would return to Earth.
鈥淪ending seeds to space and keeping them exposed to radiation聟is a meaningful study because we don鈥檛 know how long they can endure before damage is apparent,鈥� says Karl Hasenstein, a biologist with the University of Louisiana, US, who had a flax experiment on the shuttle Columbia鈥檚 last flight in 2003.
But scientists contacted by 快猫短视频 are not convinced that space radiation can induce genetic mutations. 鈥淭here is no strong evidence that particular species will be mutated in space,鈥� says Zhou. 鈥淚f there is any mutation, the mutagenic mechanisms are not well understood.鈥�
In fact, Zhou鈥檚 group submitted a proposal to NASA four years ago to fly a seed experiment similar to China鈥檚 on the outside of the International Space Station. The proposal was rejected. 鈥淭he programme office did not think it was worthwhile,鈥� says Zhou.
Junior researchers
In the past, NASA has flown seeds in space and distributed them to school children to see whether Earth seeds or space seeds grew better.
Companies like Pioneer Hi-Bred International, which is owned by chemical giant Dupont, have also decided that sending massive quantities of seeds into space is not profitable. They flew eight soybean seeds to the International Space Station in 2002. Seven of those grew into soybean plants in space and produced 87 seeds.
When scientists analysed the space seeds, they found they had a slightly higher level of carbohydrates and a little less oil than control seeds. But these figures were all within normal ranges.
鈥淲e are now testing some of those seeds to see if there were any genetic changes,鈥� says Tom Corbin, a research scientist with Pioneer Hi-Bred International. 鈥淪o far, we have not detected any.鈥�
