Recently, the Shenzhou-17 astronaut crew picked fresh vegetables grown in the "space vegetable garden", and the "space vegetables" are now picked and eaten, fresh and delicious, and the astronauts are also ready for a new batch of vegetable cultivation. So, why do we grow vegetables in the sky?What is the biggest difficulty in growing vegetables in space?Do plants grow in the same cycle in space as they do on Earth?What other animals and plants can live in the "Heavenly Palace"?Let's take a look at how the "Heavenly Palace" is realizedWhy grow plants such as vegetables in space?
The space vegetables grown by astronauts look fresh and delicious. So, do you also have questions, why do we grow vegetables and other plants in space?To sum up, there are three main reasons: the first is the use of the space laboratory platform, which can be studiedThe effects of special environments such as space microgravity on plant growth and development, physiology and biochemistry. The second reason is very practical, and that is the plants that are grownAstronauts can be provided with food, oxygen and water. Plants can absorb carbon dioxide produced by astronauts through photosynthesis to produce oxygen, which can purify the closed cabin environment to a certain extent and obtain clean airProduce food, provide astronauts with fresh vegetables and fruits, supplement vitamins and dietary fiber, and enrich astronauts' dietsIn addition, through the transpiration of plants, water purification in the closed system can also be realized, and pure water can be replenished for astronauts. The third reason is plantsIt can provide a green and fresh environment for astronautsBy taking care of plants, the pressure of astronauts can be relieved and the psychological emotions of astronauts can be positively regulated. What are the difficulties of "growing vegetables" in space?
The space environment is very different from the earth, so what is the difficulty of growing vegetables in the "Heavenly Palace"?We know that plants must have the right amount of light, water, nutrients, etc. for normal growth. Astronauts said that there are two main difficulties in "growing vegetables" in space:First, in a weightless environment, water is not easy to penetrate deep into the root system. The space microgravity environment will cause a boundary layer to form around the plant roots, and water and air cannot be separated automatically, and plants must rely on external forces to exchange substances with the surrounding environment normally. Therefore, water and nutrient supply technology is the key to space plant cultivation. The second difficulty is that there is no sunlight in the cabin, and plants that like light are not easy to grow. However, there is an artificial light source in the experimental cabinet that can provide sufficient light for the plants. How to find "soil" for growing vegetables in space?
In the general concept, there must be "soil" to grow vegetables, but in space, the use of artificial cultivation substrate for cultivation is the main way of plant cultivation, which is equivalent to a substitute for soil, so how to find a "cultivation substrate" for plants to grow?
Researchers have chosen cultivation substrates, from early ion exchange resins and solidified agar, to later rock wool, vermiculite, montmorillonite, plutonite, artificially sintered ceramsite, etc., and researchers focus on these substrate materialsA variety of water and nutrient systems for space plant cultivation have been developed. In 2016, the space plant cultivation device developed by the China Astronaut Research and Training Center successfully carried out lettuce in-orbit cultivation experiments on Tiangong-2. This is also the first time that China has artificially cultivated vegetables in space, and at that time, astronauts were not allowed to eat them in orbit, but plant samples were brought back for biosafety testing. Since then, researchers have also designedA biodegradable and reusable plant cultivation mediumThis matrix exists in the form of a block-like structure and does not shed debrisAnd it has good aeration, fertilizer retention and water conductivity. As researchers continue to upgrade the cultivation substrate and devices, the Shenzhou-14 astronaut crew is in orbitLettuce, wheat and dwarf tomatoes were successfully cultivated using plant cultivation devices, and the Shenzhou-14 astronaut crew also achieved lettuce for the first time in orbit. How do the roots of plants sink into the "soil" in weightlessness?
Gravity is not felt in space, so why can the roots of plants be able to sink into the culture medium in this weightless environment?The astronaut explained that although the space station is not guided by gravity, the roots of plants will still grow into the soil, and this is because:Plants are not only aquatropic but also water-oppressive. The medium contains sufficient water, so it is similar to the previously planted Arabidopsis thaliana and rice seedsAt the time of germination, it grows into a soil box containing water. At the same time, without the sense of space brought by gravity, the roots and stems of plants cannot grow neatly in one direction, and will appear in a more messy state. What are the advantages of the newly upgraded "Space Vegetable Garden"?
At present, the "space vegetable garden" device used by astronauts to plant vegetables and fruits in space is the second-generation space plant cultivation device newly designed by the China Astronaut Scientific Research and Training Center
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Reporter:This is the space plant cultivation technology laboratory, and this set of equipment around me is the space cultivation device called the "space vegetable garden", which is exactly the same as the cultivation device running in the space station, which plays the role of synchronous control experiment between heaven and earth, and the light, water and nutrients required for plant growth can be scientifically and automatically configured in it. Compared with the previous generation of space cultivation equipment, its biggest feature is that it realizes rotational and multi-batch planting, which lays the foundation for large-scale space planting in the future.
Yang Runze, China Astronaut Research and Training Center:The lighting component adjusts its frequency and illumination to the best light conditions for plants through the appropriate proportion of red, blue and white light we designed, this cultivation cup assembly is to provide a suitable root space for the growth of plants, similar to this part of the soil, we call it the substrate, the initial state of its upward movement is a shriveled state, through the astronaut's in-orbit water supplement, it becomes a state suitable for plant growth.
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Reporter:So is this substrate recyclable?
Yang Runze, China Astronaut Research and Training Center:Yes. Then after this growth of the plant, the inedible part can be crushed and compressed to regenerate a matrix block, which is injected with water by the astronaut to re-provide it (the plant) with suitable growth space. At the same time, it also has some slow-release fertilizer, which will also provide some nutrients for the plant, and then its water supply component here provides the same pure water as the astronauts drink. We are also currently conducting research on a new generation of plant cultivation technology, which directly supplies the water and nutrients needed by plants to the vicinity of plant roots, and at the same time through some recycling devices, the excess water and nutrients are returned, so as to reduce some waste of unusable parts as much as possible and increase the proportion of it that can be recycled.
Do plants grow in the same cycle in space as they do on Earth?
Many people may also have a question, that is, do plants grow in the same cycle in space as they do on Earth?The microgravity environment of space can have an impact on many aspects of plant growth and development. Scientists have discovered through a number of space experiments in the early stageThe microgravity environment of space may cause changes in the growth cycle of many plants in space. For example, during the work and life of astronauts in Tiangong-2, the lettuce planted and the growth cycle on the ground are similar, while the Arabidopsis thamina, which is also carried in Tiangong-2, grows slower than on the ground, but survives longer. What other animals and plants will live in the "Heavenly Palace"?
In addition to lettuce, tomatoes, Arabidopsis thaliana and rice, which have been cultivated in space, what other animals and plants can live in the "Heavenly Palace"?Scientists say that in addition to plants,The space station can also be used to breed zebrafish, nematodes and other creatures. Here, scientists can control the light, temperature and other conditions according to the suitable growth environment of different organisms, and at the same time, the automatic observation device can also regularly take pictures and record their living conditions in space, so that scientists on the ground know whether they are developing well and observe whether they live in space Xi. How do the space "fruits and vegetables" look when they return to Earth?
In terms of plant planting, space breeding is nothing newLet's go to the Hainan Aerospace Breeding Center to have a look. At the Hainan Aerospace Breeding Center, the "Space Phalaenopsis" bred in the nursery greenhouse is in full bloom. There are also a large number of vegetables bred from space seeds that have experienced "space travel" in the planting base, such as space tomatoes, space cucumbers, etc.
Space breeding, also known as space mutagenesis breeding, is one of China's major space missions. It is to send crop seeds or test-tube seedlings to space through spacecraft, using special high vacuum, cosmic high-energy ion radiation, cosmic magnetic field, and high-clean environmental mutagenesis that cannot be simulated on the ground, so that the seeds can be mutated, and then after returning to the ground, at least 4 generations of breeding, screening out new seeds, new materials, and cultivating new varieties with new traits.
Since 2013, the Hainan Aerospace Breeding Center has screened out the varieties of fruits, vegetables and flowers suitable for Hainan's climate and soil from the aerospace introduction experiments, cultivated and planted, and promoted the planting in some cities and counties in Hainan and many provinces and cities outside the island. **CCTV News Client Producer: Liang Bingqing Editor: Li Yining.