The first step
Collecting seeds is the first step of preservation, and GBOWS cooperates on this task with national partners who receive regular training from the seed bank.
Apart from seeds, collectors take specimens for verification. For future study, they record details of the plant, including where it was found, its size and the number of individual plants in the habitat.
This year, collectors from the bank visited many regions nationwide, including areas with low populations in West China and also sinkholes in the south and southwest.
At sinkholes in Mengzi city, Yunnan, researchers found two rare plant species, Petrocosmea grandiflora and Elaeagnus bambusetorum, which had not been seen for more than 100 years.
Species are targeted and prioritized if they meet at least one of three standards－they are endangered, endemic or of economic importance.
After arriving at the bank, the seeds undergo a series of processes before they can be stored long-term.
First, they are checked by botanists to ensure their "identity". Then, the seeds are slowly dried to 5 percent moisture content in a drying chamber, which maintains a temperature of 15 C and relative humidity of 15 percent.
The seeds are next cleaned before being weighed and counted manually, which is time-consuming and requires patience and an eye for detail.
Then, the seeds are placed in suitable containers and weighed on an electronic scale under a plastic cover, which prevents the results being influenced by factors such as the wind.
The weight of the seeds is recorded in grams correct to four decimal places－even more accurate than a scale for weighing gold.
Before being stored, the seeds receive an X-ray "health check". After this, they are photographed.
Seed morphology researcher Li Lianyi said, "For big seeds, an ordinary camera is enough, but for those with a diameter of 1 or 2 millimetres, photomicrography is used.
"Some tiny seeds cannot be seen by the eye, but photomicrography allows us to appreciate their spectacular shapes and colors."
After these procedures are completed, the seeds are sealed in glass bottles or jars. Each container has a barcode that can be scanned to enable scientists to view information about the seeds inside.
The containers, large and small, are stored in a huge chamber at a temperature of minus 20 C. Such chambers are freezers built underground to reduce the influence of the local environment.
The seed bank has five such chambers, covering a total of 190 square meters and capable of storing 170,000 collections.
Germination tests are conducted on a seed accession after it is banked to ascertain viability and to establish a germination protocol.
Seed revival is conducted on a palmsized cell culture dish with agar, a gelatinous substance obtained from some red seaweeds. In most cases, it usually takes a few days for the seeds to sprout.
Seed curator Li Hui said, "Some seeds remain dormant and need a little inducement to 'wake them up'-for example, a biological enzyme or an external force, such as chipping or breaking out the hard seed coating."
For seeds without a germination study, she said it sometimes takes four or five years for them to revive. "For instance, some seeds only sprout through interaction with a biological enzyme found in the intestinal tracts of birds," Li Hui said.
The bank has provided technical support for the preservation, research and use of China's wild plants. It also provides seed germination guidance services.
"Most of the orders are from forestry, grassland and agricultural colleges and research institutes," Li Hui said.
"A test is usually conducted every five or 10 years after the seeds are stored to check their ability to grow. The result is a significant part of our research on the plant."
Partnerships at work
In addition to cooperating with 105 research institutes and preservation centers nationwide, the seed bank works with international partners, including Kew Gardens in the UK, on collecting backup specimens, exchanges and research.
It holds 2,176 sets of seeds from 45 countries, with each set containing thousands of individual seeds.
Li Pei, the staff member, said, "Duplication storage is widely used in case the seeds are destroyed in natural disasters, other accidents or in wars."
She said wild plant protection is recognized globally as a crucial method of biodiversity conservation, as wild species have significant survival potential.
GBOWS has also made considerable efforts on DNA study and preservation of wildlife, she added, citing as an example protection of the Chinese yew－which is critically endangered and under top-level national preservation.
"In the past, illegal traders processed the tree bark into powder to evade the forestry policy. Thanks to development of the DNA barcoding technique, we can now not only recognize the species that the powders are made from, but also source its provenance," Li Pei said.
The aim of GBOWS is to conserve 19,000 species and 190,000 accessions in the next 15 years, she added.
"As China has rich and unique biological resources, we aim to further enhance our collections and conduct deeper research, in expectation of contributing more to biodiversity conservation, not only in China but the world," Li Pei said.
