Chinese researchers have successfully reintroduced Petrocosmea grandiflora, a critically endangered plant long thought lost, into its natural habitat in the sinkholes of Mengzi City, in the Honghe Hani and Yi Autonomous Prefecture of southwest China's Yunnan Province.

The conservation effort was led by the Germplasm Bank of Wild Species (GBOWS), operated by the Kunming Institute of Botany under the Chinese Academy of Sciences, in collaboration with the local forestry and grassland bureau.

Petrocosmea grandiflora (Image by LIU Chen)

The journey began in 2021, when researchers conducted a preliminary survey of sinkholes around Mengzi. On June 17 of that year, the researchers used drone surveillance and professional climbing teams to descend into a massive sinkhole -- over 100 meters wide and up to 100 meters deep -- to collect and study germplasm resources. There, they rediscovered a wild population of Petrocosmea grandiflora, a species that had not been seen in over 125 years.

Endemic to China, the plant was first described in 1895 by a British botanist, based on specimens collected in Mengzi by Northern Irish botanist William Hancock.

While the specimens were preserved at the Royal Botanic Gardens, Kew, in Britain, the species remained absent from scientific observation for more than a century.

The rediscovery marked a turning point. In October 2021, GBOWS researchers began asexual propagation of the species to address its scarcity in the wild and its low rate of natural reproduction. Hundreds of seedlings were cultivated in laboratories and greenhouses.

Last weekend, those lab-grown plants were returned to the wild.

Two reintroduction sites were selected. The first was the original sinkhole, which offers ideal ecological conditions and minimal human disturbance. The second site, located about 1 km away, is a shaded limestone cliff near an agricultural road, selected for its accessibility to facilitate monitoring.

To replicate the plant's natural habitat, the researchers planted the seedlings on near-vertical limestone cliffs. Long-term monitoring of the reintroduced populations will be carried out jointly by the participating institutions.

"This represents a full-circle scientific endeavor made possible by relentless effort," said Cai Jie, deputy director of GBOWS. "From the accidental rediscovery of the critically endangered Petrocosmea grandiflora, to its successful propagation in the lab, and now its return to the wild, it's a powerful testament to China's commitment to biodiversity conservation."

As part of China's national strategy to safeguard strategic biological resources and promote scientific innovation, GBOWS has been collecting, preserving and researching wild germplasm from China and its surrounding regions.

By the end of 2024, GBOWS had preserved more than 100,000 plant seed accessions from over 12,000 wild species, along with about 10,000 species and 70,000 samples of plant DNA. Its collection also includes microbial strains, fungal specimens and animal germplasm, totaling 27,000 species and 330,000 biological samples. (Xinhua)