Scientists have discovered traces of ancient «culture» of rice on the Ground

© Fotolia / alex9500Рис Yin and YangScientists have discovered traces of ancient «culture» of rice on the Ground© Fotolia / alex9500

Scientists have calculated the age of the oldest traces of rice in the sites of the ancient people in China and came to the conclusion that the first «cultural» varieties of this plant appeared 9400 years ago, according to a paper published in the journal PNAS.

«Wild rice grows in marshy terrain, and its leaves always have access to water. The leaves of domesticated rice are always at a great distance from water, and so they need to protect themselves from moisture loss, folding in a spiral. Traces of this process can be seen in phytolith – small pieces of silicon contained in the leaves of rice,» says Jianpin Zhang (Zhang Jianping) from the Institute of Geology and Geophysics KAN in Beijing.

Today, among scholars there is no clear idea about when and where was the domestication of rice. Genetic studies show that rice was «tamed» by the ancient inhabitants of Southeast Asia or southern China approximately from 9 to 13 thousand years ago, however, the first unequivocal archaeological evidence of its existence have to a much later era, 4.5 to 4 thousand years ago.

Moreover, today many scientists believe that figure could be domesticated at least three times in different parts of Asia in different historical periods. How much of modern varieties of rice are associated with these ancient cultures today is highly controversial among biologists, historians and archaeologists.

Zhang and his colleagues say they managed to find traces of the most ancient cultivated rice on the Land, studying the excavations, which were carried out in the territory of Zhejiang province in southern China in the place called Shanshan.

Here, as the scientists tell, Chinese archaeologists found traces of an ancient village residents in the «middle Kingdom» that existed in the South of China, about 8-10 thousand years ago. Among broken pots and other artifacts, scientists have managed to find a few stalks of rice and other plants, potentially pointing to the possibility of their domestication.

Stems, recalls Zhang, survived bad enough, and so archaeologists have calculated their age is not directly, through radiocarbon Dating, using deposits the slurry on the vessel walls, near which they were found. These dates, 13-9 thousands of years, caused great doubts among most scholars, as there was a possibility that the walls of the pots could be contaminated with radionuclide emissions from modern nuclear power plants and nuclear tests.

Speaking stones

Zhang’s team was able to double-check these dates and also to prove that the stalks of Sansana owned cultural varieties of rice by examining the proportion of isotopes in phytolith — particles of silicon contained in large amounts in plant cells and helps them to escape from pests and moisture loss.

As the researchers note, the shape, size and other properties of fossil plants differ for cells of different representatives of the earthly flora and they strongly depend on the conditions in which to grow rice or another plant. This allows high accuracy to determine what plants grew in one way or another in the world in the distant past by fragments of fossil plants that are preserved in sedimentary rocks and on the walls of pots.

Vitality contain small inclusions of unstable carbon-14, which scientists use to calculate the age of certain fossils and artifacts. Zhang and his colleagues have extracted a certain amount of organic matter of fossil plants and got enough «heavy» carbon to measure the exact age of the remains.

They were quite ancient – they hit the ground Sansana about 9400 years ago, making them the oldest remains of rice from human settlements known to mankind. Moreover, this figure, according to the scientists, was cultural.

This is supported by the fact that almost all vitality was bent, which would never occur with particles of silicon in the leaves of wild rice, growing in swamps. Accordingly, the figure found in Sansana, was adapted by the locals for growth in dry conditions, irrigated fields, making rice the same age as the two oldest agricultural crops – middle East millet and pumpkins from South America.

It is possible that the secrets of rice cultivation was further lost when, Shanshan ceased to exist. On the other hand, the presence of large numbers of stone artifacts in other villages of the ancient people in China who are now scientists interpretiruya as millstones for cleaning grains of rice from the husk, point to the fact that for 9 thousand years ago in the future, «China» there was a developed agriculture, which played a major role in the survival of the people of that time.