Sending seeds into space for a period of time helps scientists develop new varieties of crops that can grow faster in a different environment and help meet the nutritional needs of a growing world population. Is.
At first glance, it looks like any other wheat crop waving in the wind all over the world. But the vast fields of crops in northeastern China are no ordinary plants—they were grown in outer space.
It is a type of wheat called Luyuan 502 and is the second most widely grown type of wheat in China. The plants were grown from seeds that were placed in orbit 200 miles (340 km) above Earth's surface.
In the unique low-gravity environment at this altitude in space and outside our planet's protective magnetic shield, they made subtle changes to the DNA that created new traits in these plants that made them more drought-tolerant and Made better resistant to certain diseases.
They are an example of the growing number of new varieties of important food crops being grown on spacecraft and space stations orbiting our planet. Here they are subject to the principle of microgravity and at this point they are exposed to an infinite amount of cosmic rays, which greatly stimulate the growth and transformation of plants - a process known as space change. Known as
Some mutations leave plants unable to grow, while others can be beneficial. Some plants are able to withstand harsher and more demanding growing conditions, while others produce more food per plant or grow faster or require less water. When they are brought back to Earth, the seeds of these space-bred plants undergo careful testing and further breeding to produce viable versions of popular crops.
Some mutations leave plants unable to grow, while others can be beneficial. Some plants are able to withstand harsher and more demanding growing conditions, while others produce more food per plant or grow faster or require less water. When they are brought back to Earth, the seeds of these space-bred plants undergo careful testing and further breeding to produce viable versions of popular crops.
"Spatial variability creates beautiful mutations," says Liu Liqiang, China's leading space mutation expert and director of the National Center of Space Mutagenesis for crop improvement at the Institute of Crop Sciences of the Chinese Academy of Agricultural Sciences in Beijing.
For example, according to the International Atomic Energy Agency, Luyuan 502 yields 11 percent more than standard wheat varieties grown in China, with better drought tolerance and resistance to the most common wheat pests. Using radiation-based techniques to develop new crop varieties has strong immunity.
"Luyuan 502 is a true success story," says Liu Liqiang. It has high productivity potential and adaptability. It can be cultivated in many different areas with different conditions.
This adaptability is what makes the Luyuan 502 popular with farmers in China's vastly diverse agricultural regions and diverse climates.
According to Liu, it is one of more than 200 space-changing crop varieties developed in China in the past 30 years. In addition to wheat, Chinese scientists have developed space-breeding rice, corn, soybeans, alfalfa (a leguminous plant used for cattle fodder, also known as alfalfa), sesame, cotton, watermelon, tomato, sweet pepper, and other varieties. Prepared vegetables.
China has been experimenting with space mutagenesis since 1987 and is the only country in the world to use the technique continuously. Since then it has flown dozens of missions to carry crop seeds into orbit. Chinese scientists grew the first space-bred crop - a variety of sweet pepper called 'Yujiao 1' - in the 1990s.
Compared to traditional sweet pepper varieties grown in China, the 'Yujiao 1' variety produces larger fruits and has greater disease resistance, says Liu.
China's emergence as a global space power in recent decades has enabled it to send thousands of seeds into orbit. In 2006, China sent its largest ever shipment - more than 250 kg of seeds and 152 species of microorganisms - into orbit via the Shijian 8 satellite. In May of this year, 12,000 seeds, including several varieties of grass, barley, alfalfa, and fungi, were sent into space as part of the Shenzhou 13 mission crew that spent six months aboard China's Tianhe space station. came back
In November 2020, the Chinese sent the Chang'e-5 mission to the lunar surface, which also landed on the lunar surface, along with sending a batch of rice seeds to the laboratory to orbit the moon. According to Chinese newspapers, crops were also grown from rice seeds returned from the moon.
"We benefit from China's strong space program," says Liu. We can use retrievable satellites, high-altitude platforms and even manned spacecraft to send our seeds into space twice a year and use these space facilities for crop improvement.'
Seeds are shipped for periods ranging from just four days to several months. In this unusual environment, many changes can occur in seeds and plants. First, high-energy solar and cosmic radiation can damage the genetic material in the seeds themselves, resulting in mutations or chromosomal defects that are passed on to future generations.
A low-gravity environment can lead to other changes as well. Plants that grow and grow in microgravity (very weak gravity, such as in orbiting spacecraft) also undergo changes in cell shape and the organization of structures within the cells themselves.
In most cases, Chinese scientists take seeds into space and then replant them on Earth after returning to Earth. The plants are then screened for useful traits to determine which plants are useful for more traditional crop types.
Scientists are looking for changes that lead to larger fruits, lower water requirements, better nutritional properties, resistance to high and low temperatures, or adaptations to disease. In some cases, rare mutations can lead to advances in crop yield or adaptive flexibility.
The most promising plants are further bred until researchers arrive at a sufficiently improved seed variety to meet the needs of farmers.
Although China is currently a leading country in research into space mutations (mutagenesis), it was not the first country to experiment with space breeding. These techniques were related to some of the early experiments conducted by American and Soviet scientists using carrot cells sent into orbit by the Soviet satellite 'Kosmos 782'.
The approach relies on the same principles as 'nuclear mutagenesis', which has been around since the late 1920s. Nuclear mutagenesis accelerates the naturally occurring mutagenesis process in the DNA of organisms by exposing them to radiation.
But while 'nuclear mutagenesis' uses gamma rays, X-rays and ion beams from terrestrial sources, space mutagenesis relies on the abundance of cosmic rays that surround our planet. On Earth we are shielded from these high-energy rays by its magnetic field and its dense atmosphere, but in orbit, spacecraft and satellites are constantly exposed to this radiation, mostly emitted by the Sun.
According to Shuba Shiva Shankar, who leads the Joint Plant Breeding and Genetics Group of the International Atomic Energy Agency (IAEA) and the Food and Agriculture Organization of the United Nations (FAO), both space and nuclear mutagens (space and nuclear mutagens) Can help cut development times of new crop varieties in half.
Seibersdorf, 21 miles southeast of the Austrian capital Vienna, is home to the International Atomic Energy Agency's nuclear laboratories, and is the world's center for nuclear modifications and training. Cooperating countries that do not have their own nuclear facilities send their seeds, plant cuttings or plants to Shivshankar's team for irradiation.
Shiva Shankar says, “It only takes a few minutes to light the seeds, but it requires a lot of knowledge and skill. Each type of plant has a different tolerance. Give the seeds a dose that's too high, keep them in the irradiation too long and you'll destroy them, and they won't germinate. If you don't give them an adequate amount of radiation, they will not mutate (i.e., not produce mutations) and die out as a species as their predecessors did.'
Nuclear Energy in Food and Agriculture and the Joint Nuclear Applications Division of the World Organization for Food and Agriculture, of which the Plant Breeding and Genetics Group is a part, was founded in 1964. In the late 1920s, experiments using X-rays to induce variation (variants by mutation) in wheat, corn, rice, oats, and barley interested botanists worldwide.
By the 1950s most advanced countries had their own nuclear breeding programs experimenting not only with X-rays but also with 'ultra-violet' (UV) radiation and gamma rays.
"There was a lot of effort at that time in Europe and North America," says Shuba Shivshankar. Many new strains created by nuclear mutagenesis were released. But in the last two or three decades, many of these countries have abandoned this technique. The United States in particular has turned to transgenic technologies that create the ability to insert foreign DNA fragments into a plant's genome in the laboratory.'
However, nuclear mutagenesis did not end. Countries in the Asia-Pacific region, led by China, continued to use it confidently. They continue to populate the IAEA's database of mutagenic crop varieties, which today contains 3,300 newly developed crop varieties. Shivashankar says that while the cost of transgenic technologies may be the main motivation for some poor Asian countries to stick with nuclear mutagenesis, rich Western countries have abandoned it.
"For example, the US industrial farming sector prioritizes a handful of traits such as pest and herbicide resistance," Shivshankar says. Transgenic technologies work much better for this. But the situation is very different in Asian countries.'
Asian breeders produce seeds for many smallholder farmers who operate in highly diverse environments. Mutation of just one or two features will not be enough.
"They need more complex features," says Shuba Shivshankar. Many of these are related to climatic conditions such as heat and drought tolerance or the ability to grow in nutrient deficient or saline soils, etc. In my opinion, this cannot be achieved with transgenic technologies.
China sees it as a necessity to try to improve the genetic pool of its agricultural crops. According to Liu and his team, if the world is to feed the additional two billion people on the planet by 2050, the world will need to increase production of staple grains by 70 percent. They say the growing population in the Asia-Pacific region is most at risk of food insecurity.
According to the International Atomic Energy Agency (IAEA), China alone has developed and introduced more than 800 new varieties through nuclear and space mutagenesis, compared to the original traditional crops. All important features are improved.
One question remains, however: What's the point of sending seeds into space when it can be done in laboratories on Earth?
Liu admitted that sending seeds into space costs more than sticking them in Earth's radiation. Yet space travel seems to provide clear advantages and often produces more interesting results.
'We actually see a higher frequency of useful radiation from space radiation than from gamma rays,' says Liu. The intensity of radiation in space is much lower, but the seeds take advantage of these rays for a long time. What we call the linear energy transfer of particles and the overall biological effect is greater in space and there is a lower rate of seed damage than radiation in laboratories.'
A single irradiation gives the seeds large doses of ionizing radiation — 50 to 400 grams in just a few seconds, Liu says. On the other hand, during a week-long spaceflight, the seeds are exposed to only two milliseconds. As a result, he says, up to 50 percent of seeds do not survive harsh ground-based treatments, while nearly all seeds grown in space usually grow further.
'All these techniques are very useful and are helping us solve some very real problems,' says Liu. There are very few opportunities to carry seeds into space. We just can't rely on him.'
Now it appears that there is a renewed interest in growing food in space in other parts of the world. In November 2020, US commercial space services company NanoRacks announced plans to operate orbiting greenhouses. What will be their purpose?
To develop new varieties of crops that will be better for feeding the world as they face the threat of extinction due to global climate change. For this endeavour, the company, known for launching small satellites from the International Space Station, has partnered with the United Arab Emirates.
The UAE is a country with very little arable land of its own, meaning it has to import most of its food needs.
However, not all seeds return from space as new superplants. In 2020, European scientists sent a batch of lettuce seeds to the International Space Station (ISS). After returning to land, these plants grew more slowly than other plants.
Much of the research now being done on growing food in space is aimed at helping astronauts feed themselves during missions. For example, astronauts on the ISS have been growing and eating romaine lettuce since 2015, and a study published in 2020 found that This food is safe, and can provide a valuable source of nutrients on long missions.
But now that growing food for astronauts could prove crucial as space agencies around the world set their sights on returning humans to the moon and other planets like Mars, space food may be one of the most important of us. It will be more effective and useful for those who live here on earth.
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