三万年前种子成功发芽
Scientists in Russia have grown plants from fruit stored away in permafrost by squirrels over 30,000 years ago.
俄罗斯科学家将三万多年前松鼠埋藏在永久冻土层中的果实培育成活。
The fruits grew into healthy plants, though subtly different from modern examples of the species
The Institute of Cell Biophysics team raised plants of Silene stenophylla - of the campion family - from the fruit.
Writing in Proceedings of the National Academy of Sciences (PNAS), they note this is the oldest plant material by far to have been brought to life.
Prior to this, the record lay with date palm seeds stored for 2,000 years at Masada in Israel.
The leader of the research team, Professor David Gilichinsky, died a few days before his paper was published.
In it, he and his colleagues describe finding about 70 squirrel hibernation（冬眠，过冬） burrows in the river bank.
"All burrows were found at depths of 20-40m from the present day surface and located in layers containing bones of large mammals such as mammoth, woolly rhinoceros, bison, horse, deer, and other representatives of fauna from the age of mammoths, as well as plant remains," they write.
"The presence of vertical（垂直的） ice wedges demonstrates that it has been continuously frozen and never thawed.
"Accordingly, the fossil burrows and their content have never been defrosted since burial and simultaneous freezing."
The squirrels appear to have stashed（贮藏） their store in the coldest part of their burrow, which subsequently froze permanently, presumably due to a cooling of the local climate.