Wednesday, 5 June 2013

400-year-old plants

 Scientists say that plants that were frozen during the "Little Ice Age" centuries ago have been observed sprouting new growth.

Several 400-year-old plants have been found by researchers from the University of Alberta reportedly resurrected back to life. These icy plants called bryophytes were discovered at the Teardrop Glacier in the Canadian Arctic. Bryophytes are plant species that “dried-out during long, cold winters and then come back to life after a time.” They were “extremophiles that survive in places where other plants don’t.”

The unusual thing about these plants was that they have endured 400 years under the icy Arctic environment and have shown signs of growing. Catherine La Farge, researcher from the University of Alberta, revealed that they saw the 400-year-old plants with intact structures and green coloration. The researcher explained that about four species were regenerated out of the 24 samples.

According to La Farge, “We know that bryophytes can remain dormant for many years and then are reactivated. Nobody expected them to rejuvenate after nearly 400 years beneath a glacier. These simple, efficient plants, which have been around for more than 400 million years, have evolved a unique biology for optimal resilience. Any bryophyte cell can reprogram itself to initiate the development of an entire new plant. This is equivalent to stem cells in faunal systems.” La Farge‘s team used radiocarbon dating to conclude that the plants were living from 400 to 600 years old.

Samples of 400-year-old plants known as bryophytes have flourished under laboratory conditions. Researchers say this back-from-the-dead trick has implications for how ecosystems recover from the planet's cyclic long periods of ice coverage. The glaciers in the region have been receding at rates that have sharply accelerated since 2004, at about 3-4m per year. That is exposing land that has not seen light of day since the so-called Little Ice Age, a widespread climatic cooling that ran roughly from AD 1550 to AD 1850.

"We ended up walking along the edge of the glacier margin and we saw these huge populations coming out from underneath the glacier that seemed to have a greenish tint," said Catherine La Farge, lead author of the study. Bryophytes are different from the land plants that we know best, in that they do not have vascular tissue that helps pump fluids around different parts of the organism. They can survive being completely desiccated in long Arctic winters, returning to growth in warmer times, but Dr La Farge was surprised by an emergence of bryophytes that had been buried under ice for so long.

"When we looked at them in detail and brought them to the lab, I could see some of the stems actually had new growth of green lateral branches, and that said to me that these guys are regenerating in the field, and that blew my mind," she said. "If you think of ice sheets covering the landscape, we've always thought that plants have to come in from refugia around the margins of an ice system, never considering land plants as coming out from underneath a glacier."

Glacier retreat has accelerated in the period since 2004 - and many new species lie beneath

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