The blooming of the Amorphophallus titanium, or titan arum, constitutes a grand event for a botanical garden. Originally from the equatorial rainforests of Sumatra, Indonesia, the plant only flowers three to four times during its lifespan of nearly 40 years but given it can only do so when it has accumulated sufficient energy in its huge underground stem, time between flowering is unpredictable, spanning from a few years to more than a decade.

But then an amazing thing happened... In July, three titan arums bloomed, one right after another, at the China National Botanical Garden in Beijing. Given the extreme rarity of this event as well as the plant's short flowering period of 24 to 36 hours, the garden organized an event to allow visitors to take in this sensational scene.

"It's an incredibly special plant and we hope more people can learn about the species and protect it," Wei Yu, Executive Deputy Director of the North Garden of the China National Botanical Garden, told Beijing Review.

The titan arum happens to be one of the smelliest plants on Earth. Nicknamed the corpse flower, it has an incredibly foul smell of rotten flesh when in bloom. The flowering structure generally opens late in the afternoon, rising up to 3 meters from the ground, and the scent is released that same evening.

Scientists are still searching for the plant's main pollinators, but it is likely the initial stench tantalizes dung beetles and carrion flies who feed and lay their eggs on rotting flesh; one study by the UC Botanic Gardens in California, the U.S., has confirmed stingless bees pollinate the plant.

"The scent changes on the second day and becomes similar to that of tropical fruits," Wei said.

Today, it is not easy for titan arums to be pollinated naturally, and manual pollination is a major way to help them produce better fruits. In October, the three titan arums in Beijing's botanic garden bore fruits, reddish-orange "cherries," for the first time, setting another record for titan arum growing in China.

"From blooming to fruiting, the national botanical garden has made significant progress, laying a solid foundation for further research on the species. It is also a manifestation of the garden's capabilities in terms of scientific study, cultivation and ex-situ conservation," Wei added.

New shelter

Ex-situ conservation is the protection of plant or animal species that are not able to be protected in their natural habitats. The off-site preservation of plants entails the protection and maintenance of plant samples under controlled conditions in specific areas outside their natural habitat, including botanical gardens. "If the number of a certain genus might further decline when left in its natural habitat, we start carrying out off-site conservation," Wang Kang, Curator of the Plant Museum at the China National Botanical Garden, told Beijing Review.

It usually contains a series of research endeavors on endemic conditions and how to help reproduce these inside a lab. "Also, we should create a livable environment within the plants' original habitat to eventually transplant them back," he said, adding the ultimate goal is "returning to and living in the wild."

When applied to animals, ex-situ conservation can involve captive breeding, which is when animals are bred in captivity and then released into the wild, or by keeping animals in zoos or other sanctuaries. One successful example in China is the giant panda and its downgraded classification from "endangered" to "vulnerable" species.

Plants endemic to the moist, shady jungle of Sumatra used to face many threats in their homeland. The titan arum, for example, is under threat in its natural habitat due to land degradation and deforestation. Large areas of its forest terrain are logged for timber and to make room for oil palm plantations. It was therefore included in the Red List of Threatened Species of the International Union for Conservation of Nature, a critical indicator of the health of the world's biodiversity, in 1997.

Growing the species is difficult due to its extremely specific environmental requirements, Wei said. For example, the optimum temperature for its growth needs to be controlled between 26 and 28 degrees Celsius, with humidity levels above 80 percent.

"Today, the wild titan arum remains critically endangered. We must try and preserve its genetics to help it survive," she said.

The China National Botanical Garden has so far introduced and cultivated over 1,000 rare and endangered plants, and "it is our duty to conserve every species under threat," Wei added.

Botanic wellbeing

China has set up a fairly complete ex-situ conservation system, including botanical gardens, wildlife rehabilitation and breeding centers, germplasm resource centers, and gene banks, according to a white paper on China's biodiversity conservation released in October 2021. For plants specifically, the country features about 200 botanical gardens and arboretums exhibiting 23,000 species.

National botanical gardens have carried out off-site conservation in many places, Zhou Zhihua, deputy head of the Department of Wildlife Conservation of the National Forestry and Grassland Administration, told Guangming Daily in April.

Last year, Chinese President Xi Jinping proposed the creation of a system of national botanical gardens in places such as Beijing and Guangzhou, capital of Guangdong Province, at the Leaders' Summit during the first phase of the 15th Meeting of the Conference of the Parties to the Convention on Biological Diversity in Kunming, Yunnan Province in southwest China.

These botanical gardens, considered national plant diversity protection bases, are expected to play an important role to balance in-situ conservation, a set of conservation techniques involving the designation, management and monitoring of biodiversity in the same area where it is encountered, with ex-situ conservation.

On April 18, the China National Botanical Garden was inaugurated. Built on the work conducted by the Institute of Botany at the Chinese Academy of Sciences (CAS) and the Beijing Botanical Garden, it collects over 30,000 species of plants from all over the world, representing different regions, including an assortment of rare and endangered species.

The second of its kind in the country, the South China National Botanical Garden in Guangzhou opened to the public three months after its peer up north. The largest subtropical botanical garden in the world, it has successfully conserved 1,700 plant species, 36 rare and endangered of which have already been transplanted back into the wild.

When creating this national-level botanical system, China considered the climate zones and vegetation regions of all plant species, the development of current botanical gardens, as well as local government capacity, Zhou said.

Compared to other botanical gardens, those at the national level hold decided advantages in species collection and scientific research, which makes up the foundation of ex-situ conservation, Ye Jianfei, a senior engineer at the Institute of Botany under the CAS, told Guangming Daily.

"The strength of scientific research can provide more references about the wild survival status and genetic diversity of rare and endangered plants. Such information is essential to formulating scientific and reasonable protection measures," Ye added.

Today, dominated by national botanical gardens, China's ex-situ conservation complements the in-situ conservation in its national parks, combinedly creating a full-fledged nationwide biodiversity protection system, Zhou concluded. 

(Print Edition Title: New Ark Sets Sail)

Copyedited by Elsbeth van Paridon

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