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Frozen plants from the Little Ice Age regenerate spontaneously
Carbon dating shows they bounce back from 400 years of being stuck in a glacier.
Retreating glaciers are proving to be good news for plant scientists. Underneath one such glacier on Ellesmere Island in Canada, researchers have found plants that they believe have regrown after being entombed in the glacier for more than 400 years, since a cold period called the Little Ice Age.
These plants are called bryophyte, a group that includes mosses. They are non-vascular, which means they do not have tissue that distributes resources throughout the plant and they do not reproduce through flowers and seeds. They use spores instead. But they also possess the ability to regrow from tiny fragments of themselves through a process called clonal growth. "This ability makes bryophytes pretty tough," Andrew Fleming, a plant scientist who was not involved in the study, said.
The discovery reported in the journal Proceedings of the National Academy of Sciences was made by a team led by Catherine La Farge, an expert on bryophytes at the University of Alberta. Because the bryophytes found were not much different from similar varieties found in the wild today, La Farge used radio carbon dating to confirm the age of their find.
The plants were trapped during a period known as the Little Ice Age, between the 16th and 19th centuries, when glaciers were growing in size. Arctic glaciers have recently been retreating, and since 2004, the rate of ice melt has increased dramatically. La Farge is hopeful that in addition to these plants, the melting glaciers will release other interesting flora and fauna of that time.
This discovery does not displace the record of the oldest frozen plant to be regenerated. That belongs to a 32,000 year old specimen of Silene stenophylla, which was regrown by using tissue extracted from its frozen seeds.
These bryophytes are also not the hardiest plants we know. That title belongs to what are commonly known as resurrection plants, which are able to survive extreme dehydration. Some of these are commonly found in deserts, such as Selaginella lepidophylla found in the Chihuahuan Desert on the border of Mexico and the US.
But La Farge hopes that their discovery will spark interests in bryophytes, which are not as well-understood as their flowering relatives. Fleming agreed, saying, "Large swathes of lands across the world are covered by mosses. They represent an important source of stored carbon."
PNAS, 2013. DOI: 10.1073/pnas.1304199110 (About DOIs)
This article was first published at The Conversation.
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