2015 Volume 9 Pages 43-55
Within the tip of roots meristems of angiosperms and gymnosperms there is a small group of cells known as the quiescent centre (QC). The concept of the QC was developed 60 years ago by FAL Clowes, working in the Botany School, Oxford University, UK. To celebrate the Jubilee of the QC, a brief outline of the work that led to its demonstration by autoradiography was presented by Dubrovsky and Barlow (2015). The present article traces Clowes’s subsequent experimental studies of the QC, especially with regard to how X-irradiation became an important tool for elucidating the properties and significance of the QC for root development. Also reviewed are some of the consequences that subsequently arose from this work with radiation, in particular the concerns over the use of radioisotopes in attempts to describe the kinetics of cell proliferation in the root meristem.