Silene stenophylla
Read aloud Freeze and bring to life in a new age? This science-fiction vision has been achieved by Russian biophysicists with at least one fossil plant: from frozen remains stored in the permafrost of Siberia for more than 31, 000 years, they regenerated whole plants in the laboratory. The regenerated carnation plants were able to flower and form seeds. Permafrost soils cover a good 20 percent of the world's land surface and hold a huge biological treasure: the ice masses, some of which are several hundred meters thick, contain microorganisms and higher organisms from past millennia. In the conserved biological samples, scientists today read the history of earlier geological ages. Science has evidently proved a special service to an arctic ground squirrel, just over 31, 000. In the middle of the permafrost of Siberia, it buried a supply of seeds and fruits that it never used. In the laboratory, Russian biophysicists have now succeeded in regenerating complete plants from three of these fossil fruits of the silkworm Silene stenophylla.

A few years ago, soil scientists brought a wealth of different seeds to light from the feed cavity at a depth of 38 meters. Although some of them could be germinated, none of the seeds developed into a healthy plant. Too big was the damage that time and frost had done to the vegetable embryo. The cell researchers and biophysicists around Edith Gakhova therefore used another way to bring the fossils back to life: they isolated individual cells from the placenta of immature fruit. The vegetable placenta is easily recognizable, for example, in paprika: it forms the soft, white tissue inside, to which the seeds are attached. Using a special nutrient medium, the biologists then caused the placental cells to divide and form leaf tissue. After normal, complete plants had formed, they were even able to form flowers and seeds. This resulted in a healthy second generation.

The method is not new. In plants? unlike humans and animals? Almost every cell has the ability to differentiate into every other cell type. Feeding a single plant cell with the right hormone cocktail makes it relatively easy to make a whole plant out of it. However, growing plants from cells that had been frozen for 31, 800 years is a unique success so far.

Insight into the evolution of plant species display

Finally, the living fossils allowed us to take a look at the adaptations that have occurred in the millennia of the plant species. In fact, changes compared to today's representatives of Silene stenophylla were recognizable: the petals of modern plants are much larger and more split than those of their ancestors. In addition, the species today only has bisexual flowers? while in the late Pleistocene she apparently wore both female and bisexual flowers. It could have been an adaptation to the then cold climate, the researchers suspect. They hope that the revival of long-extinct species may yield much more information about early life forms and climatic adjustment mechanisms in the future.

Svetlana Yashina (Russian Academy of Sciences, Pushchino) et al .: PNAS, doi: 10.1073 / pnas.1118386109 © Maria Bongartz


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