The International Society of Root Research sponsored the Symposium "Root Demographics and Their Efficiencies in Sustainable Agriculture, GrassLands and Forest Ecosystems," July 14-18, 1996, at the Madren Conference Center, Clemson University, Clemson, South Carolina, USA. The conference was a continuation of a series of international symposiums on root research held every three to four years. Symposiums have also been held twice in Vienna, Austria, and once in Uppsala, Sweden, and Almaty, Kazahkstan prior to the meeting at Clemson University. The sponsoring society has made a particular effort in these symposia to include root scientists from the former Soviet Union because of the importance of exchanging information on a worldwide basis. This symposium continued and promoted that effort by providing travel grants to several scientists from that region; however, funds for that purpose were limited. Therefore, in compiling these proceedings, a number of papers from scientists from the former Soviet Union and former Warsaw Pack countries have been included even though the scientists were not actually present for the SymPOSIum.

The decade since the publication of the third edition of this volume has been an era of great progress in biology in general and the plant sciences in particular. This is especially true with the advancements brought on by the sequencing of whole genomes of model organisms and the development of "omics" techniques. This fourth edition of Plant Root