Walking on the streets of autumn every year, those golden ginkgo biloba leaves are always so beautiful that people can't take their eyes off them.
But it is unbelievable that this ubiquitous ginkgo tree is listed as an endangered species.
What kind of vicissitudes of life have Ginkgo biloba gone through to get into today's predicament? We might as well step into the long history of Ginkgo biloba and explore the origin and fate of this ancient species.
1. The life history of ginkgo: the oldest seed plant on the earth
Ginkgo biloba, also known as Ginkgo biloba, is one of the oldest surviving gymnosperms and the only one of the Ginkgo biloba family that has survived to this day.
It has a prehistoric legacy of 250 million years ago and is known as the "living fossil of the plant kingdom", recording and witnessing the long evolution of life on the earth.
Dating back to the late Carboniferous period, 300 million years ago, the original ancestors of Ginkgo biloba had already appeared and flourished on Earth.
At that time, seed plants had just appeared, angiosperms had not yet emerged, and gymnosperms were still the dominant force in terrestrial vegetation.
It was against this backdrop that ginkgo biloba arose, and together with ferns and stone pines, it formed the main body of the vast woodland of that era.
In the Early Jurassic period 200 million years ago, there were nearly 200 species in the Ginkgo family, which were widely distributed.
Different types of ginkgo biloba, each with its own style, dominate the ancient forest.
They thrive at low latitudes and gradually expand to higher latitudes, spreading almost throughout the peat bog belt.
Ginkgo biloba was accompanied by a variety of giant reptiles, pterosaurs, and early dinosaurs, who also rested in the shade of the ginkgo tree and enjoyed the delicious taste of the young leaves of the ginkgo tree, which undoubtedly witnessed the rich and colorful scene of species in that era.
Second, after geological changes, ginkgo biloba is on the verge of extinction
At the end of the Permian period, life on Earth experienced a great shock, and at the same time, Ginkgo also suffered a heavy blow of fate.
In the late Jurassic period, 180 million years ago, the ginkgo population began to shrink in large numbers, and at the end of the Cretaceous period 100 million years ago, a huge extinction event swept the earth, killing countless species, including Ginkgo biloba in North America and Europe.
In the aftermath of this catastrophe, Ginkgo biloba is on the verge of extinction worldwide.
Of all the Ginkgo biloba plants, only a handful of populations are scattered in a corner of Chinese mainland, and they have become the last hope of this ancient species.
Just when the ginkgo population was already endangered, the earth entered the Quaternary ice age 10 million years ago.
The expansion of the polar ice caps, the expansion of glaciers to the mid-latitudes, the accumulation of large amounts of snow and ice, the decline of sea levels, and the dry and cold climate have swept through much of the Northern Hemisphere, completely destroying the already fragile ecological environment.
In such an environment, North America and Eurasia, where ginkgo biloba was once distributed, have completely become their forbidden land, no longer suitable for the survival of ginkgo, and they are dying one after another.
By the last glacial maximum, 210,000 years ago, Ginkgo biloba was on the verge of extinction on Earth.
If no miracle happens, this ancient species, which has existed for hundreds of millions of years, will be wiped out in this geological change.
3. From China to the world, Ginkgo biloba has regained its vitality
At the critical moment when ginkgo biloba was about to become extinct, China's Qinling, Wushan and other places became the Noah's Ark that it escaped.
After the Quaternary Ice Age, the Earth entered the warmer and wetter Holocene, and as glaciers receded and temperate forests expanded again, Ginkgo biloba was able to recover from the haze of the Ice Age and regain its vitality in this blessed land.
They re-sprout leaves, blossom and bear fruit, and slowly spread in a suitable environment, and although the starting point is small, the ginkgo biloba has finally passed the catastrophe of life and death near extinction.
In this sanctuary in China, it has made a huge leap from endangered to safe, and after recovering in Qinling and other places, Ginkgo biloba has begun a new migratory journey.
Archaeological evidence suggests that ginkgo biloba was introduced to the Japanese archipelago from China as early as the 4th century BC, and during the Nara period, it became a garden ornament for Japanese aristocratic society.
In the late 17th century, with the increase of exchanges between the East and the West, ginkgo biloba was brought to the Netherlands in Europe, and soon took root in England and other countries, attracting great interest from botanists at the time.
In the 18th century, European ginkgo biloba was introduced to North America, and in just one century, it completed the spread of the journey from China in the east to the Americas.
It can be said that under the impetus of civilizational exchanges, ginkgo biloba has achieved a great renaissance from Asia to the world, and an ancient species that was once on the verge of extinction has been integrated into modern life around the world.
In recent years, botanists have used DNA technology to trace the extant Ginkgo populations in depth.
The results showed that the genetic composition of Ginkgo biloba in the world was very close to that of wild species in mainland China.
This confirms the fact that the ancestors of ginkgo biloba around the world can be traced back to Chinese populations.
It was the preservation of the "ark" in China that Ginkgo biloba was given a chance to survive and reproduce on the earth, and although it is not what it used to be, China is still the birthplace and genetic homeland of this ancient species.
It can be seen that while civilization spreads species, it should also spread the beautiful feelings of reverence for life and love for nature.
We are not only the inheritors of life, but also the guardians of life.
4. Why is it endangered? Genetic homogeneity leads to a lack of resistance
In modern society, large-scale transplantation and cultivation have been carried out by humans in order to develop and utilize ginkgo.
More than 90% of the world's ginkgo forests are the result of artificial introduction, but the ancestors of these cultivated ginkgo biloba are very limited.
At present, most of the world's main cultivated strains originate from a very small number of wild species in China, and these "clonal" propagation has led to a very low genetic diversity of existing cultivated Ginkgo.
Different from the natural world, the simplification of the cultivated environment also restricts the effective genetic recombination of Ginkgo, which leads to the increasing survival risk of cultivated Ginkgo.
Unlike artificial cultivation, wild populations can achieve a high degree of genetic recombination and adaptive selection, but the current distribution of wild Ginkgo biloba in China is very limited.
Except for a few scattered small communities, the main wild Ginkgo biloba is only distributed in very few areas such as Qinling Mountains and Wushan.
Genetic exchange and gene flow between them are almost non-existent and cannot form an effective "gene pool".
The range and scale of wild species are still uncertain, but it is certain that they are far from meeting the needs of maintaining genetic diversity.
The simplification of cultivated Ginkgo biloba, coupled with the distribution limitation of wild populations, has led to the overall resistance of the existing Ginkgo population.
In the event of disease and disaster, these genetically similar ginkgo biloba will not be able to resist it, and like the extinct Big Mac banana in the past, the entire variety may be wiped out by the disease.
5. How to protect this ancient tree?
(1) Protect wild populations
An important way to protect the Ginkgo biloba species is to protect its wild population.
At present, the main wild ginkgo biloba is distributed in Qinling, Wushan and other places, and these natural distribution areas should be strictly protected to avoid human destruction.
At the same time, it is necessary to strengthen the population monitoring of wild ginkgo, discover new populations or population distribution changes in time, and include them in the scope of protection.
Nature reserves can be set up in the vicinity of the area, or measures such as introduction can be taken to increase the number of wild populations.
It is very important to protect the wild gene pool of Ginkgo biloba, which is related to the improvement of the overall genetic diversity of Ginkgo biloba species.
Only abundant wild species can provide strong support for the future of ginkgo.
(2) Scientific introduction and cultivation
While protecting wild populations, it is also necessary to adopt scientific and reasonable introduction and cultivation, which can not only enrich the genetic diversity of cultivated populations, but also help to breed new varieties with stronger stress resistance.
Individuals with rich genetics should be selected from wild populations, artificially cultivated and cultivated, and new strains with different gene types should be created by means of hybridization, which can enrich the genetic diversity of the whole cultivated population.
At the same time, molecular markers and other technologies can be used to screen out new varieties with better traits such as disease and insect resistance and cold resistance.
The cultivation of these varieties can improve the environmental adaptability and resistance of the overall cultivation of Ginkgo.
and (3) global cooperative protection
Considering the global distribution of Ginkgo, conservation efforts require the cooperation of various countries, and an international database can be established to share information and research results on Ginkgo conservation in various places.
It is also possible to consider establishing a germplasm resource bank to collect seeds and samples of Ginkgo biloba from different regions to provide sample support for global conservation research.
If conditions permit, a protective base can also be established in a safe area.
Countries can also carry out technical cooperation on the introduction of ginkgo biloba, scientific research, etc., share conservation experience, and improve the level of global ginkgo protection.
(4) Inherit culture and awaken responsibility
In addition to technical means, it is also necessary to inherit the ginkgo culture and awaken people's responsibility to protect.
Ancient ginkgo trees have witnessed historical changes and represent the resilience of life, and this spirit needs to be passed on from generation to generation, so that the ancient ginkgo trees can be included in the protection of cultural relics, and science popularization and education can be carried out to let more people understand the history of ginkgo.
When people realize the value of this ancient tree, they will also consciously take on the responsibility of protecting it, and only by evoking a common cultural identity can we truly protect it.
From wild populations to scientific introduction, from technical means to cultural identity, only by all-round protection can we make this 250-million-year-old tree continue to develop in the depths of the earth's century.
VI. Final Remarks
Trees have their own life course, and humans play an important role in it.
I hope that through this article, everyone can see the ginkgo biloba from the surface to the inside, from the scene to the feelings, cherish the last vitality of this 200-million-year-old tree, and also warn human beings of the responsibility to protect their homeland.
Let us watch this ancient light of life and all the life on this planet.
Resources
Institute of Physics, Chinese Academy of Sciences.Why is ginkgo so common, why is it an endangered plant?2022-11-03
Forestry Science and Technology Development, 2015, 29(01): 118-122.
CAO Fuliang. Chinese ginkgo[M]. Nanjing:Jiangsu Science and Technology Press, 2002.