By Wu Yuehui, Yu Jianbin, People’s Daily
The third batch of space scientific experimental samples from China’s Tiangong space station were
delivered to scientists after a return capsule, carrying astronauts of the Shenzhou-14 crew, touched
down at the Dongfeng landing site in north China’s Inner Mongolia autonomous region on Dec. 4,
Beijing Time.
The returned experimental samples included three cold packs of rice and Arabidopsis, and a bag
with four boxes of container-free materials.
Rice, the main crop for humans, is a major candidate crop for the life support system in future
manned deep space exploration.
Rice breeding under space microgravity is one of the important directions of space botany
research. To ensure long-term survival in space, humans must make sure that plants can complete
the alternation of generations and successfully reproduce in space.
It was the first time in history that the full life-cycle growth experiment of rice was completed in
space. Previously, only thale cress, rape, peas and wheat had successfully grown from seed to seed
in the space environment, but the rice had not been able to complete the full growth cycle in such
circumstances.
The life-cycle growth experiments of rice were handled by Zheng Huiqiong, a researcher at the
Center for Excellence in Molecular Plant Sciences under the Chinese Academy of Sciences, and
her team.
Flowering is a crucial stage for plant reproductive development. The team also systematically
studied the effects of microgravity on flowering in space using the model plant Arabidopsis
Several life sciences experiments were done during 120 days in orbit. Experimental seeds of rice
completed the entire growth process from seed to seed, and relevant images were acquired from
space for analysis. The rice was grown after the pruning and it yielded the second crop of mature
seeds in space.
Besides, the experiments also completed the analysis and sampling on seed germination, seedling
growth and flowering of Arabidopsis under space microgravity.
Preliminary results showed that rice plants became looser in space with larger leaf angles. Short-
grain rice grew shorter while the height of tall-grain rice was not significantly affected. Besides,
the spiral upward movement of rice leaf growth controlled by the biological clock was more
accentuated in space.
Moreover, the ratooning rice can sprout two ears of rice 20 days after pruning in space, which
confirms the possibility of growing ratooning rice in a small closed environment. It has provided
new ideas and a solid basis for the efficient production of crops in space.
It marked the first time in the world to apply ratooning rice technologies in space, and is expected
to significantly increase the yield of rice per unit of volume.
Scientists for the first time studied the key biological clock-controlled genes that regulate
photoperiodic flowering in space. They found that for Arabidopsis, the genes’ response to a
microgravity environment is significantly different from that on the ground. It has provided a new
direction for using modified flowering genes to make plants better adapt to microgravity in space.
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