Tuesday, February 21, 2012

Flower Offers New Hope for Pleistocene Park

Arctic Ground Squirrel in
Denali National Park
Scientists with the Russian Academy of Science in Moscow have reported that they have successfully germinated a flower from a 32,000 year old seed-bearing fruit.  The fruit was collected and deposited in a midden by an ancient Arctic Ground Squirrel.  The ground squirrels create the middens, stuffed with seeds, fruits, and other food sources to help them during periods when food is scarce.

The midden, and its fruit, were discovered in the arctic tundra of Siberia.  The middens that researchers, Svetlana Yashina and the late David Gilichinsky, were searching for were sealed by wind-blown sediment and buried 125 feet below the surface where they were less likely to be contaminated by extant rodents depositing extant arctic plant seeds.  Some of the excavated ancient burrows contained more than 600,000 fruits and seeds.

Flower grown from 32,000 year old seeds. 
Photo by Svetlana Yashina/AP
Additionally, the depth of the middens in the tundra soil means that they were permanently frozen at -7 deg. C.  This cool temperature may have acted as a storage freezer to help preserve the seeds, however in some experiments freezing temperatures have also been shown to damage seeds and severely reduce the likelihood of successful germination.

The germinated ancient flowers share similiarities with modern Narrow-leafed Campion (Silene stenophylla), but exhibit some small differences like narrower petals that are more splayed apart and slower average root growth.

The age of the seeds was verified through radiocarbon dating of the placenta in the fruit from which the seeds originated.  Additionally, a chemical analysis of the placenta exhibited high levels of sucrose and phenols, both of which help provide freeze tolerance for some organisms.

If the age of the flowers can be independently verified, and seeds can be successfully germinated again in other labs, then this discovery may bode well for resurrecting other plant species, including those that may have gone extinct.  This would be good news for researchers trying to recreate Pleistocene ecological conditions in the tundra of Siberia.

Caribou male in Denali
National Park
Researchers with Pleistocene Park have been working to (re)introduce large grazing herbivorous species back into parts of Siberia in an effort to recreate ecological conditions similar to those that would have been present during the Pleistocene Epoch, which included grassland steppe habitat.

The ability to re-introduce extinct plants from the Pleistocene may increase our understanding of the ecological interactions between steppe plants and grazers, which included mammoths, moose, bison, musk ox, horses, and caribou.