What is a botanical garden? You may have never visited it correctly!

The National Botanical Garden was established on April 18 this year. Its predecessor was the Beijing Botanical Garden established in 1956. Later, due to various reasons, the Beijing Botanical Garden was divided into two: the South Garden managed by the Chinese Academy of Sciences and the North Garden managed by the Beijing Municipal Government. Today, under the background of the construction of the national botanical garden system, the South Garden and the North Garden are reunited, and they will also cooperate with botanical garden colleagues across the country to make overall arrangements and reasonable layouts, and work together for the cause of biodiversity conservation in our country.

National Botanical Gardens. Copyrighted image, unauthorized reproduction

So, when it comes to botanical gardens, what do you think botanical gardens are for? In addition to viewing plants, what other functions does a botanical garden have? Today, let us follow Mr. Wang Kang, the director of the National Botanical Gardens Science Museum, to learn about the interesting stories of botanical gardens.

01

What does the botanical garden do?

Actually, a botanical garden is a plant-themed museum that focuses on collecting three things:

1. Living plants are the plants you see in botanical gardens or the plants being experimented in nurseries;

2. Dead plants , i.e. specimens;

3. Documents related to plants , including books, paintings, notes, etc., all materials related to humans and plants. The main task of the botanical garden is to use these materials, specimens, and living plants to carry out botanical research; at the same time, it is also necessary to export beautiful gardens and superb gardening to attract people to the botanical garden, so that there is an opportunity to convey botanists' understanding and knowledge of plants to the public, so that the public will be interested in nature, animals and plants, and botanical gardens.

Therefore, you are all the breadwinners of the botanical garden, and you are the reason for the existence of the botanical garden. Visitors' satisfaction is crucial, so the botanical garden must pursue beauty and be people-oriented. If the botanical garden is not well managed, dirty and messy, and you all go to the botanical garden with your hands covering your nose, it will be the end of the botanical garden.

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Is it enough for a botanical garden to have beautiful environment, beautiful park, beautiful plants and beautiful staff? Obviously it is not enough.

With the development of the times, the functions of botanical gardens are also undergoing a series of changes. Early botanical gardens were mainly focused on the development and utilization of plant resources, while modern botanical gardens have undergone a slight functional change, and the protection of biodiversity has become an important task. This is not because the botanical gardens have changed, but because the world has changed. With more people, plant resources have become insufficient, or it can be said that they have been over-exploited by humans, or squeezed by human activities, the number has decreased, the area has become smaller, and the ecosystem has become fragile. In order to protect those species that are seriously threatened, modern botanical gardens have carried out ex situ conservation work.

02

What is ex situ conservation?

The opposite of ex situ conservation is in situ conservation . In situ means right where you are. For plants, the main way to conserve in situ is to establish national parks, nature reserves, forest parks and other protected areas, and the work of in situ conservation is mainly undertaken by these protected areas. Ex situ conservation, on the other hand, means moving plants to other places, and the ex situ conservation of plants is mainly undertaken by botanical gardens. Ex situ and in situ are two complementary methods, and neither is indispensable.

Ex situ conservation is not simply about digging plants from the wild and bringing them to a botanical garden. In science, ex situ conservation has a definition and connotation. It is the last chance for survival for organisms that are about to become extinct. How do we understand ex situ conservation? In what circumstances is ex situ conservation necessary? Let's take a specific example to explain.

The photo below shows a large-flowered Cypripedium in Beijing, which may be the most breathtaking plant among the 24 orchid species that are distributed wild in Beijing. It used to be seen on many hills, but with the development of tourism, excessive collection, and frequent human activities that have disturbed the living environment of the large-flowered Cypripedium, this plant has become less and less common and harder to see. In this case, in situ conservation is obviously no longer able to keep this species healthy and reproduce in the wild, so ex situ conservation becomes particularly important.

Cypripedium macranthum, Photographed by Wei Yao

In the National Botanical Garden, Dr. Zhang Yu's team began studying Cyperus rotundus in 2004, conducting a one-stop exploration of the Cyperus rotundus's resources, growth environment, symbiotic bacteria, seed germination, and return to the wild, solving each problem one by one.

The seeds of orchids are very small , as fine as dust, because they have lost their endosperm during the long process of evolution. Most orchids have lost their endosperm, but they need nutrients during the germination process, so what should they do?

Under natural conditions, the germination of these seeds can rely on symbiotic bacteria to provide nutrients. Without symbiotic bacteria, the Cypripedium plants will hardly germinate. However, to date, scientists know very little about the symbiotic bacteria of orchids and are still at a stage where they have no idea where to start. At present, facing the two urgent needs of artificial cultivation and ex situ conservation, the focus of Cypripedium researchers around the world is how to make Cypripedium orchid seeds germinate and increase the germination rate without symbiotic bacteria .

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In addition, there is another peculiar point about Cypripedium plants, that is, Cypripedium plants in temperate regions have a mechanism that makes their seed coats very thick and woody . Under natural conditions, this phenomenon may be a protective measure for the plant itself, but in the laboratory it brings another problem - how to break the woody seed coat and make the seeds germinate quickly . This is also another research focus of Cypripedium researchers. If you want to solve this problem, you need to explore all control factors such as seed maturation time, culture medium, hormones, external organic matter, and the pH value of the entire culture medium.

After nearly 20 years of hard work, Dr. Zhang Yu's team has now returned Cypripedium grandiflorum to the wild in Beijing. In addition, they have also helped the Huanglong Nature Reserve in Sichuan to carry out in-situ conservation of Cypripedium plants. More importantly, they have trained talents and forces to carry out conservation work in the nature reserves in Beijing and the Huanglong Nature Reserve in Sichuan.

There are species in Beijing that are even less numerous than Cyperus dasyphylla, such as the first-class protected plant Baihuashan grape , the second-class protected plant honeysuckle , and the maple-leaf clematis that everyone particularly likes. Although the maple-leaf clematis is relatively abundant, if it is not protected, it may be endangered in a few years due to its high beauty. From this we can see that the species that are included in our protection list are not only those with small numbers or populations, but also some species that are likely to become less in the future.

Lilac honeysuckle (Lonicera oblata), Photographed by Mu Xianyun

Baihuashan grape (Vitis baihuashanensis), Photographed by Mu Xianyun

It seems that it is necessary to carry out artificial intervention and ex situ conservation work for the plants mentioned above: Cypripedium grandiflorum, Vitis vinifera, Honeysuckle with lilac leaves, and Clematis chinensis. These ex situ conservation works do not have to be limited to botanical gardens in cities, but can also be carried out in areas close to the plants' origins or in similar areas.

Maple Clematis (Clematis acerifolia), Photographed by Wei Yao

In the process of studying and protecting these plants, we found a characteristic: the higher the endangered degree of a species, the more problems it will have , such as pollination problems, fruiting problems, fertility problems, seed dispersal problems, etc. It is because these plants encounter challenges that they cannot bear that they will face a reproduction crisis. At this time, we need to carry out endangered mechanism research in ex situ conservation, prescribe the right medicine, and take artificial intervention to gradually increase the population in number and gradually restore the richness of genetic diversity.

Of course, there are some exceptions. The endangerment of some plants is entirely caused by human activities . Changing human activities and collection and utilization habits may be the most difficult part of conservation work. For example, some plant populations are very small and the distribution area is very narrow, but as far as the plants themselves are concerned, there is no bottleneck in their reproduction and survival. If there is no interference, although the population is not prosperous, it should have no problem surviving healthily. However, humans want to build hydropower projects in its distribution area, and the design height of the reservoir happens to submerge the largest population.

There are not many cases like this, but they do exist. The five-leaf maple is probably the most well-known example. For these plants, ex situ conservation may be the only hope. In a sense, this is not a scientific problem. Such a problem is difficult for anyone to solve. At this time, how to find a reasonable, appropriate, compromise and fair solution is a real test of human wisdom.

Acer pentaphyllum

The upgrade from Beijing Botanical Garden to the National Botanical Garden has brought us new opportunities and challenges. In the face of the functional transformation, how can we work with the public and people from all walks of life who care about the botanical garden to make the botanical garden more beautiful and better meet the people's needs for the botanical garden? I think we may need to do the following three things:

1. Use better exhibitions, better activities and courses to increase the public's stickiness to the botanical garden , so that those around us who love plants and nature can get the opportunity to learn and be learned from the botanical garden's audience, gaining both benefits and contributions, and gaining a sense of accomplishment and satisfaction;

2. Relying on the resources of the National Botanical Garden, build a scientific communication and popular science education platform for field scientific research, introduction and collection, gardening and cultivation ;

3. In line with the primary and secondary school curriculum, we will develop a national botanical garden science education curriculum plan for primary and secondary school students and science teachers. I hope that everyone here and all the friends who have heard this sharing can join us in loving life and cherishing life, not only caring for animals, but also caring for plants. All the beauty of this world may be related to the plants and trees around us. Their genes and potential are the basis for human survival. Caring for them is caring for ourselves.

Finally, I would like to say that the predecessors planted trees to provide shade for the future generations. The China National Botanical Garden is a "small sapling" that was just planted this year. In the future, we will plant more "saplings" all over the country to build our national parks and national botanical gardens system. I hope that these "small saplings" can be loved by everyone, grow up healthily, and grow into "big trees" to provide a sustainable umbrella of protection for our descendants and the motherland we deeply love.

This article is based on the speech given by Wang Kang (Director of the National Botanical Garden North Garden Science Museum and Professor-level Senior Engineer) at the Starry Sky Forum.

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