Wednesday 22 February 2012

Ice Age Seeds Buried By Squirrels and Resurrected By Russian Scientists

The 31,800 year old specimen of Sylene stenophylla
Recently, the vast plains of permafrost in Northern Siberia have yielded many fantastically preserved fossils. They have been mummified by the cold to such a degree that mammoths with bones, internal organs, soft tissue, flesh, hair and even extractable sections of genetic information have been retrieved from the ice. Plants and seed specimens have also been common finds. Seeds are built to last: strong enough to resist incredible physical forces.

In the BBC programme, 'How to grow a planet,' geologist turned palaeobotanist Ian Steward loaded seeds into a shotgun cartridge and blasted them at over the speed of sound at a solid target to prove their hardiness. Their casings did not even crack. They can be buried under miles of earth and rock, survive dessication, intense cold and even radiation and still mature into plants. Seeds are one of the main reasons why plants are a global force. If one looks at a mighty oak tree and then its seed, the humble acorn, this fact seems almost impossible.

Yet it is their natural hardiness that has allowed them to do this, creating entire forests from a handful of seeds smaller than sand grains. Now their incredible properties of resistance have been taken to a whole new level as Scientists led by David Gilichinsky at the Russian Academy of Sciences have succeeded in taking a plant seed which has been held in cryostasis for over 30,000 years, from the Pleistocene epoch, and sown it. Against all the odds, it took root and sprouted, revealing a species that has not existed on this planet for millennia.

On the frozen edge of the Kolyma River in North-Eastern Siberia, in an ancient pantry harboring seeds and other stores, an Arctic ground squirrel burrowed into the dirt and buried a small, dark fruit from a flowering plant. The squirrel’s prize quickly froze in the cold ground and was preserved in permafrost, waiting to grow into a fully fledged flowering plant when unearthed again. The seed was buried at a depth of 125 feet in soil that has never thawed with an avergae temperature of -7 degrees Celsius for, ± 300, 31,800 years.

The famous animations of Scrat, the Ice Age sabre-toothed squirrel
attempting to bury his icon acorn in the ground may be more accurate
than previously thought
The scientists took samples of placental tissue from the seed and fed them a series of nutrients to induce root growth. The 'seeds' took root and were subsequently transported to pots. Over the course of a year, they grew and grew eventually developing flowers and fruit before giving up seeds for the first time in 30,000 years. The plant itself was a member of a then extinct species Sylene stenophylla. A modern version exists and is known as the narrow-leafed campion.

A specimen of this was grown alongside its ancient counterpart. They both showed very different characteristics in terms of growth, primarily that the modern version sprouted roots twice as fast and the Pleistocene twice as many buds. It is likely that the differences in the Pleistocene version were adaptations for life in a cold environment rather than damage during their time in the earth. While the team looked at such factors up to and including damage from gamma rays produced by the decay of radioactive elements in the crust, they found no evidence to suggest that they had inhibited the growth and development of the seed.

'We consider it essential to continue permafrost studies in search of an ancient genetic pool, that of preexisting life, which hypothetically has long since vanished from the Earth's surface,' the authors wrote in a paper published in Proceedings of the National Academy of Sciences. This experiment proves the hardiness of life, revealing that there may be creatures still living or hibernating in the supposedly barren soils of other planets such as Mars or Titan.