Ginkgo is so common, why is it an endangered plant?

In late autumn and early winter, there is always a sunny afternoon. The moment we step out of the door, we will suddenly find that the ginkgo trees outside the door are swaying with golden leaves, shining brightly, embellishing the autumn like guards and watching over the winter.

Perhaps in the eyes of most people, ginkgo is just a touch of golden color in autumn photos, but in the eyes of scientific researchers, it has colorful "colors" . How much do you know about this beautiful and mysterious plant?

Core Photography

Origin and distribution of Ginkgo

When it comes to ginkgo, you may have a question: why does ginkgo seem to be everywhere, but it is a national first-class wild protected plant?

This is due to a variety of factors, the first of which is its unique evolutionary and taxonomic status .

Ginkgo (Ginkgo biloba L.) is native to China and belongs to the phylum Gymnospemae, family Ginkgoaceae, genus Ginkgo (Ginkgo L.), a single family, single genus, single species of plant. It is a relic species preserved after the Quaternary glaciation. Since its origin in the late Paleozoic era, it has experienced a long evolutionary history and is known as the "living fossil" of the plant kingdom .

Ginkgo Fossils

Image source: Wikipedia

Currently, the most recognized reliable Ginkgo fossils can be traced back to the Carboniferous period 280 million years ago. The Ginkgo genus was once extremely prosperous in the Mesozoic Era, and the earliest reliable Ginkgo fossils can be traced back to the Early Jurassic period 180 million years ago.

Fossil data show that there were at least 20 genera and more than 150 species of Ginkgo plants from the Jurassic to the Cretaceous period, and more than 10 genera and more than 100 species have been discovered in China alone.

The Yima Ginkgo fossil is now in the Henan Provincial Geological Museum.

Image source: See watermark

After the prosperous period from the Jurassic to the Early Cretaceous, the number of Ginkgo species decreased sharply under the influence of glacial movement from the end of the Tertiary to the beginning of the Quaternary. All the Ginkgo plants growing in North America, Europe and other places became extinct. After the Pliocene, only one species of Ginkgo survived (the one we can see), which was named G. biloba.

Fortunately, China was less affected by glacial erosion, which provided a refuge for the species during the Quaternary Ice Age. This also makes China the only country in the world that may have natural ginkgo trees.

Schematic diagram of the radiation evolution of important molecules in Ginkgoales from the "prototype" hairy leaves (Zhou Zhiyan, 2003)

Ginkgo has a proven history of cultivation in my country as long as a thousand years. It was planted in the south of the Yangtze River during the Three Kingdoms period, and was already grown in the Central Plains during the Tang Dynasty. It became more common during the Song Dynasty. From a global perspective, ginkgo was introduced to Japan from China in the sixth century, and was introduced to the Utrecht Botanical Garden in the Netherlands in 1730, the Royal Botanic Garden in the UK in 1754, and the United States in 1784.

China is the world's largest ginkgo country, with more than 90% of the world's ginkgo germplasm resources. Ginkgo is distributed in all provinces (regions) except Heilongjiang, Inner Mongolia, Qinghai, Tibet and Hainan. The key distribution provinces (regions) include Shandong, Jiangsu, Guangxi, Zhejiang and more than 20 others, and nearly 30 key towns.

Shanghai Ancient Ginkgo Tree No. 001

Image source: Shanghai Release

However, although ginkgo can be seen everywhere now, most of the ginkgo we can see are cultivated artificially. However, the number of plants is not the decisive factor in judging the rarity of plants. The diversity of their genes and the distribution of wild populations are the most important.

Therefore, only naturally existing ginkgo can represent the genetic diversity of this species, and only by protecting the natural ginkgo resources can we truly protect this ancient species. However, according to current research, the distribution and number of wild ginkgo populations are extremely rare, and there is even great controversy in the academic community as to whether there are still wild ginkgo in China.

Cultivated Ginkgo

Image source: Pixabay

Academician Zhou Zhiyan, a famous paleontologist, believes that the current ginkgo has actually entered a period of evolutionary decline. The decline of Ginkgo species and the reduction of wild distribution areas also indicate the decline of the natural population of Ginkgo. On these two levels, it is inevitable that Ginkgo will be designated as a national wild protected plant.

Image source: China Government Network

http://www.gov.cn/zhengce/zhengceku/2021-09/09/content_5636409.htm

How much is Ginkgo worth?

Every September and October, there is an endless stream of people picking up seeds under the ginkgo trees. After peeling and cooking, the seeds can become delicious food, but what most people don’t know is that ginkgo is actually a treasure. In recent years, it has been highly valued by countries around the world for its unique edible, medicinal, material, ornamental, greening, protection and scientific research value .

Fresh ginkgo nuts

Image source: Wikipedia

The trunk of the ginkgo tree is straight and tall with a graceful posture. It is emerald green in spring and summer and golden yellow in late autumn. It is an ideal tree species for landscaping, highways, forest networks, and windbreaks . It is listed as one of the four major long-lived ornamental tree species in China.

Ginkgo leaves are rich in medicinal ingredients such as flavonoids, lactones and polyprenols, which can lower the cholesterol level in human blood, prevent arteriosclerosis, and have special therapeutic effects on cardiovascular and cerebrovascular diseases; Ginkgo nuts are rich in starch, crude fat, sucrose, vitamins and various trace elements. China's ginkgo nut production and output value rank first in the world, and the development level of China's nuclear ginkgo represents the world level; Ginkgo wood is known as "silver fragrant wood" and is a rare and precious timber species used for high-end furniture and luxurious decoration.

Ginkgo biloba: a versatile tree that can be used for both fruit and leaves

Image source: Internet

According to research and calculations, the economic income from planting ginkgo timber forests is equivalent to 13 times that of planting fir in the forest area, and the economic benefits are very significant. In addition, ginkgo is also a key tree species in the national strategic timber reserve construction.

Ginkgo is also the oldest relict species among existing seed plants. It has unique phenomena such as leaf-seed ginkgo, weeping-breasted ginkgo, and male gametophytes with motile flagella , providing good genetic resources for systematic development, cell and molecular biology research.

Ginkgo biloba seeds

Male gametophyte development in Ginkgo biloba

What are the variations and varieties of Ginkgo?

People often only have limited impressions of ginkgo, which has fan-shaped leaves and turns yellow in autumn. Although the modern ginkgo is a single family, single genus and single species, during the long process of evolution, through natural hybridization and artificial selection, the seeds and leaves of ginkgo have undergone a rich morphological variation.

Since the 1980s, researchers have used phylogeography and molecular marker techniques to explore the evolution and genetic diversity of Ginkgo. The results show that compared with other gymnosperms, Ginkgo has rich genetic variation.

Based on these variations, ginkgo varieties are becoming more and more diverse, and different ginkgo varieties show rich differences in traits, mainly in terms of plants, leaves, seeds and cores .

Image source: Wikipedia

There are currently 59 ginkgo varieties in the database of the International Union for the Protection of New Varieties of Plants (UPOV). China is the country with the most authorized ginkgo varieties, with a total of 24 authorized new ginkgo varieties, including nuclear varieties such as "Shannongguo 1", "Shannongguo 2", "Shannongguo 5", "Nanlinguo 1", and "Nanlinguo 2", as well as ornamental varieties such as "Shannongyin 1", "Shannongyin 2", "Wenbi", "Xiajin", and "Dieyi".

Image source: Unsplash

In addition to the UPOV database, we have found more than 300 other ginkgo varieties through monographs, the Internet and other channels. The varieties include leaf color variations such as golden leaves, white leaves, variegated leaves, and golden ribbons; leaf shape variations such as ear leaves, wedge leaves, multi-lobed leaves, drooping leaves, needle leaves, herringbone leaves, and barrel leaves; plant shape variations such as narrow crowns and drooping branches; nuclear shape variations such as round seeds, bells, Buddha fingers, eldest sons, and plum cores; and specific trait variations such as drooping nipples and leaf seeds.

Ginkgo biloba

With its ever-changing appearance, ginkgo is quietly changing people's stereotype of its solemnity.

A variety of ginkgo varieties

Image sources: UPOV, China Forestry Information Network, etc.

The secret of ginkgo's longevity?

The "living fossil" Ginkgo biloba is the only tree species in the Ginkgo family that survives to this day. It is speculated that parts of China were not directly impacted by the Pleistocene glaciation, thus becoming a potential refuge for some dioecious plants.

There is increasing evidence that the natural distribution area and potential refuge of Ginkgo populations are the Tianmu Mountains in eastern China and the Yunnan-Guizhou Plateau in southwestern China.

Photo by Xu Shanshan

As for the ginkgo itself, due to its unique morphological, physiological and genetic characteristics, it has created the current situation of a large number of ancient ginkgo trees. Ancient trees are treasures among forest germplasm resources, and ancient ginkgo trees are a shining pearl among these treasures.

In the long process of geological changes and changes of the times, ancient ginkgo trees are not only witnesses of the long history, but also symbols of the level of social civilization.

Image source: Pixabay

Research by the team of Professor Xing Shiyan, a famous ginkgo expert at Shandong Agricultural University, shows that there are currently 49,120 ancient and famous ginkgo trees measured and counted in China, distributed in 23 provinces (autonomous regions and municipalities), including Hubei, Jiangsu and Shandong.

The team further described the growth locations, growth characteristics, ancient tree culture and other related information of 6,019 of the ancient and famous ginkgo trees, and the results were published in the monograph "China's Ginkgo Germplasm Resources".

Image source: Unsplash

The tenacity of ginkgo trees is awe-inspiring. In Hiroshima, Japan, there are still a few ginkgo trees that survived the atomic bomb explosion in 1945. In Shengsheng Garden in Linyi, Shandong, there is also the largest ancient ginkgo complex found in China.

This community was first planted during the reign of Emperor Kangxi of the Qing Dynasty. It was cut down by the Japanese army when they occupied Linyi in 1938. It was destroyed again during the Great Steel Production Campaign in 1958. After more than 60 years, the current ginkgo forest was formed. Inspired by the strong vitality of ginkgo, the garden was named Shengsheng Garden, which means endless life.

Image source: Sohu

The mystery of ginkgo's tenacious vitality and longevity has always been a hot topic for researchers. After observing the cambium of ginkgo trees of different ages, some scholars found that the expression of genes related to cell division is almost "consistent" , even for ginkgo trees over 600 years old.

Professor Wang Li's team at Yangzhou University studied some genes that regulate antibacterial and anti-insect related proteins and obtained similar results.

Image source: Pixabay

In addition, there are a large number of latent buds at the junction of ginkgo roots and stems. When the main trunk is damaged, it will stimulate the development of latent buds, thereby forming a phenomenon of multiple trunks. Eventually, the multiple trunks will replace the main trunk and continue to exist. This may be one of the secrets of ginkgo's longevity.

Although the molecular biology research on ginkgo longevity is not very in-depth, I believe that with the continuous advancement of forest biotechnology, there will be more exciting interpretations of the mechanism of ginkgo longevity.

Top left: The "World's No. 1 Ginkgo Tree" at Fulai Mountain in Ju County, Shandong Province;

Top right: The "Second Largest Ginkgo Tree in the World" at the White Horse Temple in Xintai, Shandong;

Bottom left: Ginkgo biloba community in Shengsheng Garden, Linyi, Shandong;

Bottom right: Five generations living under one roof ginkgo trees in Tianmu Mountain, Zhejiang (Source: Chinese Ginkgo Germplasm Resources, edited by Xing Shiyan)

Culture and Protection of Ancient Ginkgo Trees

The ancient ginkgo trees have stood for thousands of years, witnessing the development of Chinese civilization, like a scholar with a wealth of knowledge, quietly stored in a deep temple, growing in a deep river valley, or proudly standing in a remote forest; along the way, there may be lingering incense filling the road, or a surging river flowing through the valley, or a dangerous peak that is out of sight and hanging high in the sky...

Image source: Unsplash

The fusion of all these images brings together a painting of ginkgo trees that embody the spirit of an ancient gentleman. Its pride and grace are like the strength hidden in a corner of our thoughts, eternally filling our lives with tenacity and composure.

In the Song Dynasty, Li Qingzhao wrote in "Auspicious Partridge·Pair of Ginkgo": "She is so graceful and elegant that she can be your slave even if you offer her a sweet orange. Who will pity her for wandering in the world? Her jade-like bones and icy skin will never wither." This is the most vivid summary of ginkgo.

Image source: Unsplash

Ancient ginkgo trees are a world natural heritage that is unimaginable to human beings and a milestone in revealing the mysteries of nature. Breeders believe that an ancient ginkgo tree is a gene bank, archaeologists believe that an ancient ginkgo tree is a living antique, and historians believe that an ancient ginkgo tree is a history book.

Every ancient ginkgo tree is worthy of our care, but ancient ginkgo trees are scattered and difficult to manage in a unified manner. In addition, due to the constant changes in the environment and the strong interference of human behavior, some ancient trees are gradually declining or even endangered, and the situation is serious.

Image source: Unsplash

In recent years, the protection of ancient trees has received attention from natural resource departments in various places , and the rejuvenation of endangered ancient trees has been gradually carried out. Through technical measures such as flower and fruit thinning, tree restoration, soil improvement, pest and disease control, and grafting restoration, some ancient trees have regained their luster. In addition, the continuous improvement of off-site and facility preservation technology has provided a more solid guarantee for the protection of the precious genotypes of ancient ginkgo trees.

Image source: Unsplash

In short, ginkgo has become a natural ladder for us to understand nature. Through the efforts of generations of researchers, its magical codes have been slowly revealed layer by layer, and have been compiled into one academic work after another with important scientific research value, opening one window after another for everyone to have a comprehensive and in-depth understanding of ginkgo.

With its unique charm, ginkgo attracts crowds of people to stop and watch. I sincerely hope that with everyone's continuous protection and efforts, ginkgo will always be with us in the autumn sunshine, witnessing the prosperity and changes of the great era together.

Image source: Pexels

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This article is reproduced from the official account "Shanghai Natural History Museum" (ID: snhm01)