Siberian permafrost

Seventy-one percent of the Earth's surface is covered by blue ocean water, and the remaining 29 percent is land on which humans depend. But 20% of the land is permafrost.

High latitudes such as Europe, northern Asia, and North America have permafrost all year round because of the relatively low temperatures. And some mid- and low-latitude regions have permafrost on high mountains and plateaus because of higher altitudes and lower temperatures.

Permafrost, also called permafrost or tundra, is a layer of earth and rock that remains frozen for several years or even centuries. The colder the temperature, the thicker the permafrost layer. For example, the permafrost in the Arctic, where the average temperature is -15°C, can reach more than 1000 meters, but the permafrost in the 48°N, where the average temperature is about 0°C, is only about 1 meter thick.

The thicker the layer of permafrost, the longer it has existed, because permafrost is the result of increasing over the years. In general, under the influence of leaching processes, the permafrost layer is very deficient in nutrients. Most of the permafrost is inorganic matter, with another part of soil clay and humus. The humus structure is usually rich in nutrients, but 70% of the humus in the permafrost layer is fulvic acid, which has little nutritional value.

The permafrost is a natural, long-established "natural refrigerator", so to speak. Once something is frozen in the permafrost, there is moisture to keep it alive, but there are no nutrients and no suitable temperature for it to further transform its form. The longer it takes, the thicker the layer of permafrost, and the longer the sealed object is preserved.

Siberia has a cold climate, so there is a very thick layer of permafrost. Here, scientists have found mammoths, cave lion cubs, woolly rhinoceros cubs, lemmings and other animals, but in the "natural refrigerator" in the existence of tens of thousands of years of living creatures, although because of the low-temperature environment, the slow decomposition process of microorganisms and maintain the state of life, but the vital signs have long disappeared, so people get only a corpse.

But in 2012, scientists from the Russian Academy of Sciences succeeded in reviving 30,000-year-old plant seeds in the permafrost of Siberia.

30,000-year-old willow flycatcher seeds

In February 2012, a study was published in the Proceedings of the National Academy of Sciences. The report was about Russian scientists resurrecting 30,000-year-old plant seeds, which caused a great sensation at the time. This was because the oldest plant seeds resurrected by humans at the time were date palm seeds of the palm family that had been stored for about 2,000 years. The record was set by scientists in Israel in the 1970s, so it had been held for more than 40 years before 2012.

But this time the seeds of the resurrected plants were 15 times longer than the coconut seeds had been stored. You know that the longer the seeds are stored, the less likely the plant will be revived, and the survival rate is geometrically decreasing. And the Russian scientists are like accomplishing an almost impossible task, which is what triggered the heated debate.

It is understood that the seeds of the revived plant are those of willow-leaved flycatcher, which were first discovered in 2007. The seeds were found 38 meters underground in the permafrost near the Kolyma River in northeastern Siberia, surrounded by seeds and fruits of many other plants, and scientists speculate that this was once a place where squirrels stored their food. But for some reason, the area was covered with permafrost, so the seeds were preserved.

Scientists have measured the geology of the area using radiocarbon dating and found that the permafrost layer in which the seeds were stored probably formed between 28,000 and 32,000 years ago. In other words, the seeds have been preserved for about 30,000 years. Scientists removed them and compared the morphology of tens of thousands of plant seeds before finally identifying them as willow flycatcher seeds.

Willow-leaved flycatcher is currently only found in China, and can only be seen in the wild on rocky mountain forests at altitudes of 2100 to 2300 meters. It belongs to the class Angiospermae, order Staphylinidae, family Staphylinidae, and is one of more than 200 genera of flycatchers.

Once the scientists had the seeds, they first recorded and analyzed them. Immediately afterwards, seeding tests were quickly carried out, with the intention of comparing the changes in the plant over 30,000 years by observing the successful plantings.

But disappointingly, the seeds were successfully sown, but the scientists also put a lot of effort into simulating the growth environment required by the seeds. However, the seeds did not germinate, perhaps because the seeds had existed for too long, so the cells lost their vitality. That is to say, the seeds have been "completely dead", humans can not be planted to observe 30,000 years ago willow fly grass, such results let the researchers were a blow.

But modern technology has turned things around, as scientists have solved the problem of seed deactivation using cloning technology.

Generally, angiosperms will be able to keep their seeds longer than gymnosperms because they have a hard outer shell on their surface. Scientists have found that most of the cellular tissues of willow flycatcher seeds are completely dead, but the tissues on the ovules have not been completely deactivated because they are in the central part of the seed.

The scientists immediately performed a "laparotomy" on the seeds and succeeded in extracting the inactivated cell tissues from the seeds. The cloning technique was then carried out on these cells, and the flycatcher was successfully revived by reculturing the cells and tissues. This cloning technique resulted in the production of 36 living plants, which were the oldest multicellular life forms that had been revived.

Scientists carefully observed the resurrected Willow Flycatcher, and from the germination to the flowering stage, there was little difference between the 30,000-year-old Willow Flycatcher and the modern Willow Flycatcher.

It wasn't until after Willow Flycatcher bloomed that scientists discovered differences in the flowers, with the ancient Willow Flycatcher petals being wider and the depth of the apical slit greater than modern petals.

Most importantly, the seeds produced after flowering of the ancient willow flycatcher have a 100% germination rate, while modern willow flycatcher seeds have a 10%-14% lower germination rate.

How did scientists manage to resurrect 30,000-year-old seeds?

The most important reason why Russian scientists were able to successfully revive 30,000-year-old willow flycatcher seeds is that people used advanced scientific and technological means. As early as 1902, a German botanist named Harbrandt pioneered the idea of growing a complete living plant from some of its tissue cells. However, the means to realize this technology were not available at that time, so the idea was only at the idea stage.

It wasn't until 1958 that the American scientist Steward and his colleagues succeeded in turning this idea into reality. Together with his colleagues, they collected tissues from the healed parts of carrots and, after several experiments, successfully grew a carrot seedling. The world's first seedling grown from somatic cells successfully took root and blossomed. Since then, the bottleneck of plant cloning technology has been completely broken, and a new door has been opened in the field of plant breeding.

Since the 1960s, the rapid development of science and technology has led to a significant increase in the level of plant tissue culture, and many plants have begun to use this technology extensively. This technology is being used in many fields such as toxin removal, rapid propagation, cell engineering, genetics, genetic research, and artificial seedlings.

Therefore, the most important reason why scientists were able to successfully resurrect 30,000-year-old willow flycatcher seeds is that people already had very advanced plant tissue cultivation technology at that time. With the advanced technology and rich cultivation experience, people were able to see the flowering and fruiting of the 30,000-year-old plant. In addition, the ability to preserve the seeds in the permafrost is also a very important reason.

First of all, the shells of these seeds are very well protected, and the shells of angiosperms largely protect the embryo and germ of the seeds. For example, a batch of lotus seeds was once unearthed in 1950 in Liaoning Province, China, and these seeds had been stored for 1300 years. Since the seed coat of lotus seeds was intact, scientists from the Beijing Botanical Garden of the Chinese Academy of Sciences successfully planted and cultivated them in 1956.

If the seed shell of willow flycatcher has been destroyed this time, there will certainly be no living cells now, 30,000 years later. If there are no living cells, no amount of advanced technology can bring it back from the dead.

There is also the fact that these seeds are hidden in a thick layer of permafrost. 38 meters of permafrost protects the seeds from other animals, saving them from the risk of being eaten. Coupled with the sub-zero temperature environment, it is difficult for microorganisms to decompose the seeds, so they have a chance to be revived.

The significance of resurrection seeds

Scientists resurrected 30,000-year-old seeds of willow flycatcher, which on the one hand allows people to study the knowledge in the field of plant evolution, genetics and mutation in comparison with modern willow flycatcher. On the other hand, it also shows that the human level of plant tissue cultivation has reached a new peak.

If we can apply the results of the research in plant breeding. For example, if the secret of 100% germination rate of Willowherb is cracked, it can be widely applied to other plants with low germination rate, so that these plants which are not easy to grow and germinate can have higher germination rate. For example, if the secret of 30,000 years of genetic traits is deciphered, we can apply it to plants that have excellent performance after accidental mutation, so that we can ensure that the excellent plant genes can continue to be inherited.

Perhaps someday in the future, plant tissue culture can be developed into more advanced animal tissue culture. Perhaps when the technology is mature, we will not only be able to revive plants, but perhaps we will also be able to revive prehistoric animals. At that time, the way humans explore history will be completely overturned, and we will have a more vivid, three-dimensional and intuitive understanding of the earth's creatures in the past.

The entire cultivation time for reviving 30,000-year-old willow flycatcher seeds is not even long. But it took decades for humans to go from conceiving the idea of living cell cultivation to realizing plant tissue cultivation. Perhaps our current technology is not enough to resurrect ancient prehistoric animals, but as long as we can persevere in our research, we will one day be able to build on our strengths and fulfill the prophecy we have made today.