30,000-year-old plants are brought back to life

Fruit seeds stored by squirrels more than 30,000 years ago have been found in Siberian permafrost and regenerated into full flowering plants by scientists in Russia.

The seeds of the herbaceous Silene stenophylla are the oldest plant tissue to have been brought back to life, according to researchers Svetlana Yashina and David Gilichinsky of the Russian Academy of Sciences.

The latest findings could be a landmark in the research of ancient biological material and the race to potentially revive other species, including some that are extinct.

The previous record for viable regeneration of ancient flora was with 2,000-year-old date palm seeds at the Masada fortress near the Dead Sea in Israel.

The latest success is much older, with researchers saying radiocarbon dating has confirmed the tissue to be 31,800-years-old, give or take 300 years.

The study, appearing in the Proceedings of the National Academy of Sciences, describes the discovery of 70 squirrel hibernation burrows along the bank of the lower Kolyma river, in Russia’s northeast Siberia, and bearing hundreds of thousands of seed samples from various plants.

“All burrows were found at depths of 20-40 metres from the present day surface and located in layers containing bones of large mammals such as mammoth, wooly rhinoceros, bison, horse, deer, and other representatives of fauna from the Late Pleistocene Age,”said the report.

The permafrost essentially acted as a giant freezer, and the squirrel seeds and fruit resided in this closed world – undisturbed and unthawed, at an average of -7°C – for tens of thousands of years.

Scientists were able to grow new specimens from such old plant material in large part because the burrows were quickly covered with ice, and then remained “continuously frozen and never thawed”, in effect preventing any permafrost degradation.

In their lab near Moscow, the scientists tried to grow plants from mature S. Stenophylla seeds, but when that failed, they turned to the plant’s placental tissue, the fruit structure to which seeds attach, to success-fully grow regenerated whole plants in pots under controlled light and temperature.