Liquid Nitrogen and Seed Bank. Botanists Save Bellflower From Extinction
Botanists are saving a unique plant, Adenophora liliifolia (commonly called ladybells), from extinction. They sow and grow it in laboratories, and the best seeds go to the seed bank, where they are frozen in liquid nitrogen. After a few years, the seedlings from the PAS Botanical Garden will return to the Kampinos Forest.
Ladybells (Adenophora liliifolia) is a plant with purple and white flowers that resemble bells. It is found in Asia and Europe. In Poland, its presence is confirmed in less than 30 locations. Depending on the region, it is considered a critically endangered or extinct species.
`It is a protected species in all European countries, in which it occurs, and it has its western range border in our Poland. So our populations are very valuable from the genetic point of view. They are simply unique`, emphasises Dr. Anna Rucińska from the Botanical Garden of the Polish Academy of Sciences in Powsin.
Dr. Rucińska reminds that in natural conditions, Adenophora liliifolia was most often found in thermophilous oak forests. Nature co-shaped this kind of forests with people grazing cattle and pigs in the forests. Grazing of animals limited the growth of some bushes, allowing sunlight to reach the lower parts of the forest more easily. As a result, photophilous species developed.
`Recently, forest management related to grazing animals has been abandoned, which is why luminous oak forests have begun to change their character`, says Dr. Rucińska. In the 20th century, Adenophora liliifolia could be found at about 100 sites in Poland. Currently, these are only several sites`.
Scientists from the Botanical Garden of the Polish Academy of Sciences carry out a conservation programme that involves strengthening existing populations with new specimens, grown from seed material obtained from the same populations.
To restore Adenophora liliifolia populations in natural conditions, they obtain seeds from plants that still occur in nature, collect them and preserve them in a cryogenic seed bank.
"We mainly secure seeds in a cryogenic seed bank. The seed bank is based on storage in liquid nitrogen. This is the first seed bank of this type for endangered species in Europe`, emphasises the head of the Florintegral project.
Seeds are carefully selected. `We conducted research aimed at assessing the genetic relationships between different ladybells populations and based on these studies we selected individuals that had the highest level of genetic similarity to the populations once found in the Kampinos National Park`, the botanist explains.
She reminds that the temperature of liquid nitrogen is minus 196 degrees Celsius. Special equipment allows it to be kept in the liquid phase or in the form of vapours. `Large tanks filled with permanently liquid nitrogen are required. Each time such a tank is opened and the samples are secured, liquid nitrogen evaporation occurs. We need to supplement it. Liquid nitrogen inhibits the aging process of seeds`, the researcher explains.
At low or ultra-low temperatures, the seeds will last for a long time. Cryogenic methods have already proven effective in the storage of crop seeds. For endangered plants, scientists use additional procedures, which allows to protect seeds even better.
Under controlled conditions, scientists also sow and grow plants, after which they bring the plants thus obtained into oak forest.
`As part of the FlorIntegral project, we have partnered with the Kampinos National Park. We want to bring the patches of oak trees to a state that will allow to restore species characteristic of this habitat, including ladybells`, declares Dr. Rucińska, the project leader.
Ultimately, scientists want to recreate Adenophora liliifolia habitats in the Kampinos National Park, and then restore the endangered species. They only introduce individuals that are most similar to those that once existed there. Adenophora liliifolia is to become a natural, unique element of the Polish landscape of thermophilous oak forests.
Dr. Anna Rucińska adds that seeds of over half of the endangered species of Polish plants are preserved in Powsin.
Author: Karolina Duszczyk
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