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Ancient Plant Stem Cells Provide Clue Into Pre-Historic Tree Formation

Joanna Lawrence
5th June, 2016

Researchers at the University of Oxford have found an ancient population of plant root stem cells in a fossil verified to be 320 million years old. These cells are believed to have given rise to the roots of ancient trees and plants. In addition to revealing the most ancient root stem cells to date, the study highlights the first time an actively growing root has been fossilized. In essence, the plant was captured in time and frozen. According to Alexander Hetherington at Oxford Plant Sciences, the discovery offers a unique glimpse as to how roots grew hundreds of millions of years ago. Plant stem cells are located at the tip of the roots and shoot in clunks referred to as “meristems”. These ancient stem cells found at Oxford are quite unique compared to those found today. The ancient stem cells had an entirely different method behind their cell cycle that was elusive to scientists until now. The study reveals that root formation in trees, plants and shrubs was so different 320 million years ago that most of the species from then are believed to have no living ancestors. Clearly, plant life was more diverse than we thought. Ancient trees are believed to be responsible for the ice age itself. Some trees back then grew to over 50 metres in height and were able to pull carbon dioxide directly out of the atmosphere, leading to a mass cooling event that led to the ice age. Scientists examined the soil where the stem cells were found via extensive mineral analysis to reveal the cells were once located within one of the very first tropical rainforests on the planet. The trees that grew in this soil are believed to have given rise to many of the leading coal sources we have today ranging from Europe to the United Kingdom. With this interesting glimpse into how plant formation occurred long before we existed, we can begin to paint a better picture of what the world looked like between the Carboniferous and Permian periods, at least within the Plantae kingdom. Study Source: http://dx.doi.org/10.1016/j.cub.2016.04.072