While monitoring the
retreat of the Teardrop Glacier in the Canadian Arctic, scientists have
found that recently unfrozen plants, some of which had been under ice
since the reign of Henry VIII, were capable of new growth.
While in the field, the researchers from the University of Alberta
discovered that the receding ice--which has doubled from 2 meters per
year in the 1990s to 4.1 meters per year in 2009--had uncovered lots of
mosses and other non-vascular plants, including more than 60 plant
species. Upon careful examination, the scientists were impressed by how
well preserved the delicate bodies were; the stems and leaf structures
were perfectly intact, although some of them were only one-cell layer
think. Using radiocarbon dating, they determined that those plants have
been frozen for 500 years since the Little Ice Age when the glacier was
at its maximum.
The most surprising
thing, however, was that many of the plants were showing signs of life:
they had green tips and fresh off-shoots, even though they have only
been ice-free for less than a year and were just a few centimeters away
from the glacier margin.
Plants have long
been reported to emerge from beneath Arctic glacier ice. One study from
1966 stated that “vigorous new moss shoots appear in places to be
growing
directly out of the underlying dead moss.” It concluded the new
growth was a result of germination of either dormant or migrant spores
on the “dead moss mats.”
That and all other publications since then, presumed that the emergent
vegetation was dead. Now for the first time, researchers realized that
at least part of that re-growth is coming from the Ice Age plants
themselves. “This is an important distinction,” explains the lead
scientist Dr. Catherine La Farge from University of Alberta.
To confirm their
observations in the field, the team of scientists collected samples of
these recently uncovered plants and grew them in the lab under careful
monitoring. The results were unprecedented: a third of the plants
re-grew! The discovery was reported in the prestigious journal
Proceeding of the National Academy of Sciences (PNAS) this week.
The second important finding about this scientific discovery is that the
plant cells grown in the lab acted as stem cells: they were capable of
regenerating the entire plant regardless of which part of the body did
the original cell come from. This capability is known as totipotency.
Spontaneous plant regeneration from a few viable cells is well-known in
mosses. But until now it had never been observed in 500 year old
specimens.
These results demonstrate that plants buried by ice hundreds of years
can remain dormant and serve as an unrecognized genetic reservoir on
recently uncovered land, concludes Dr La Farge.
Source: news.mongabay.com
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