Hormone clue to root growth

PA 187/09 Plant roots provide the crops we eat with water, nutrients and anchorage. Understanding how roots grow and how hormones control that growth is crucial to improving crop yields, which will be necessary to address food security and produce better biofuels. Now an international group of scientists, led by the Centre for Plant Integrative Biology at The University of Nottingham, has shed light on how a plant hormone is crucial in controlling the growth of plant roots. Plant growth is driven by an increase in two factors: the number of cells, and their size. It is already known that the plant hormone gibberellin controls how root cells elongate as the root grows in the model plant Arabidopsis thaliana . Now a paper appearing in Current Biology describes for first time how this hormone also regulates the number of cells in the root in order to control root growth. Gibberellin normally acts by signaling the removal of proteins which repress growth, and so promotes root cell production.