At 20:09 on December 4, Beijing time, the return module of the Shenzhou 14 manned spacecraft successfully landed at the Dongfeng Landing Field.
On the same day, the third batch of space science experiment samples of the manned space station that went down with the cabin was delivered to the space application system at the landing site, and returned to Beijing in the early morning of the next day, and was successfully transported to the Space Application Engineering and Technology Center of the Chinese Academy of Sciences. The overall space application system and related experiments The personnel checked the basic state of the experimental samples, and after confirming that the returned samples were in good condition, they were handed over to the relevant experimental scientists smoothly.
The returned samples include 3 biological sample cold packs and 1 non-container sample bag, of which 3 biological sample cold packs contain experimental samples of rice and Arabidopsis, and the non-container sample bag contains 4 boxes of non-container material experimental samples .
Rice and Arabidopsis seeds experienced a full life cycle of 120 days.
Rice is the main food crop for human beings, and it is also the main candidate food crop for the life support system of manned deep space exploration in the future.
The use of space microgravity for rice breeding is also one of the important directions of space botany research.
If human beings want to survive in space for a long time, they must ensure that plants can successfully reproduce seeds in space.
In the past, only Arabidopsis, rapeseed, pea and wheat have been cultivated from seed to seed in space, but rice, the main food crop, has not been able to complete the whole life cycle of rice in space.
In the life science project of my country's space station, Zheng Huiqiong's research team of the Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences undertook the "Molecular Mechanism of Flowering Regulation of Higher Plants under Microgravity Conditions", and carried out the whole life cycle space of rice from seed to seed for the first time in the world. Culture experiment.
At the same time, flowering is a prerequisite for seed formation. Using the model plant Arabidopsis thaliana, the research team also systematically studied the impact of space microgravity on plant flowering.
The project carried out experiments in orbit for a total of 120 days, and completed the cultivation experiments of the whole life cycle of Arabidopsis and rice seed germination, seedling growth, flowering and seeding.
During the period, the astronauts carried out three sample collections in orbit, including rice sample collection at the booting stage on September 21; sample collection at the flowering stage of Arabidopsis thaliana on October 12, and sample collection at the maturity stage of rice and Arabidopsis seeds on November 25.
After collection, the samples at the flowering or booting stage were stored in a low-temperature storage cabinet at minus 80 degrees Celsius, and the samples at the seed maturity stage were stored in a low-temperature storage cabinet at 4 degrees Celsius.
On December 4, the sample returned to the ground with Shenzhou 14.
After the samples were handed over in Beijing as planned, they were transferred to the Shanghai laboratory for further testing and analysis.
The main experimental content of this space project includes: the cultivation experiment of the whole life cycle of rice from seed germination, seedling growth, earing and seed setting was completed on orbit, and the image was obtained for analysis; the space ratooning rice was successfully cultivated after crop cutting And produced mature seeds (second stubble); image observation and analysis of Arabidopsis seed germination, seedling growth, and flowering key genes regulated by three different circadian clocks in response to space microgravity were completed on-orbit, and samples were collected on-orbit.
Preliminary experiments found that the plant type of rice became looser in space, mainly because the angle between stems and leaves became larger; dwarf rice became shorter, and the height of tall rice was not significantly affected.
In addition, the spiral upward movement of rice leaf growth controlled by the circadian clock is more prominent in space.
The flowering time of the rice space is slightly earlier than that of the ground, but the filling time is extended by more than 10 days, and most of the glumes cannot be closed.
Both flowering time and glume closure are important agronomic traits of rice. Both of them play an important role in ensuring the full reproductive growth of plants and obtaining high-yield and high-quality seeds. This process is regulated by gene expression, and the returned samples will be used for further analysis.
Conduct ratooning rice experiments in space and obtain seeds of ratooning rice.
Two spikes of rice can be regenerated 20 days after cutting the plant, which shows that it is feasible to regenerate rice in a closed environment with a small space, and provides new ideas and experimental evidence for the efficient production of space crops.
This technology can greatly increase the yield of rice per unit volume, and it is also the first regenerative rice technology tried in space in the world.
For the first time, the key genes of the spatial circadian clock regulating photoperiod flowering were studied.
Using gene mutation and transgenic methods, three kinds of Arabidopsis thaliana with different flowering times were constructed, namely: early flowering, delayed flowering and normal flowering (wild type), through the observation and analysis of the growth and development of Arabidopsis in space , and found that the response of key flowering genes to microgravity was significantly different from that on the ground, and the flowering time of Arabidopsis that bloomed earlier on the ground was also greatly prolonged under microgravity conditions.
In addition, after the circadian clock gene mutation, the hypocotyl of Arabidopsis thaliana was excessively elongated, indicating that the expression of the circadian clock gene is very important for maintaining the normal shape of Arabidopsis growing in space and adapting to the space environment. Adapting to the microgravity environment of space provides a new direction.
The follow-up research team will further use the returned materials to conduct in-depth analysis of the molecular basis of Arabidopsis adaptation to the space environment.
At the same time, 4 boxes of experimental samples of non-container materials were returned.
The non-container material test cabinet is the first domestic and the second similar experimental facility in the world to successfully operate in orbit. So far, it has achieved stable operation in orbit for more than 590 days, successfully completed the in-orbit experiment of 7 boxes of material samples, and successfully heated the samples 73 pieces.
Through long-term on-orbit experiments, the space application system has made breakthroughs and mastered a series of key technologies, obtained a large amount of important scientific data, revealed a number of new phenomena in space experiments, and produced some preliminary results through ground analysis and research. Published many papers in internationally renowned top journals.
In the future, scientists will continue to accelerate the research on the deep supercooling solidification process of new metal alloys and the measurement of thermophysical parameters in order to obtain the key conditions for the high-performance preparation process on the ground and guide the preparation of new materials on the ground.
Reporter Wu Yuehui and Yu Jianbin (Source: People's Daily)