It’s common knowledge that plants grow up from the ground, supported by a root system, but until now scientists were unable to understand how that process starts during fertilization at a cellular level. An international team of scientists that includes a University of Kentucky researcher has visualized how the fertilized egg cell divides unequally after fertilization. 

From this unequal cell division, one cell works toward developing the top part of the plant including stem, leaves and flowers while the other works on root structure.

Using a new live-cell imaging system, Tomokazu Kawashima with the UK College of Agriculture, Food and Environment, and his colleagues from Japan and Austria were able see how egg cells of Arabidopsis, a model plant used in research, lose their intercellular structure after fertilization and then reorganize.

“This paper provides the first insight into understanding how plants initiate embryo development at the cellular level, opening a new way of investigating sexual plant reproduction important for agriculture,” said Kawashima, an assistant professor in the UK Department of Plant and Soil Sciences.

The scientists identified two components within the cells, microtubules and actin filaments, which play a major role in cell structure and cell division. These components lose their structure at fertilization and then reorganize the cell to form an elongated shape with one smaller cell on top of a larger cell.

Researchers in Japan developed the live-cell imaging system. Kawashima played an important role in developing color markers for various components of the plant cell so scientists could fully see how those worked during and after fertilization.

The finding was recently published in the Proceedings of the National Academies of Science. The full article is available online at http://www.pnas.org/content/early/2016/11/21/1613979113.