This review considers root evolution by attempting to define the root and, …

• Abstract
• Introduction
• What is a root?
• The functions of roots in extant plants in relation to the capabilities of other below-ground plant structures
• The biogeochemical context of the early embryophytes
• The early (Palaeozoic) evolution of embryophytes and the origin of roots
• Implications for plants and for their environment of increased rooting depth by vascular plants during the Palaeozoic
• Conclusions
• References
• Tables

Conclusions 

An understanding of the evolution of roots based on fossil evidence is only being obtained slowly. This fossil evidence does not support a monophyletic origin of roots in polysporangiophytes. Molecular genetic studies on root development in extant lycophytes and euphyllophytes (including seed plants) should give further information on this point.

Acknowledgments

Work in JAR's laboratory on roots has been, and/or is, supported by AFRC, BBSRC and NERC, and DE's research on early land plants by NERC. Comments from Dr KR Skene and Dr W Bruce, and by Professor WG Chaloner and another, anonymous, referee have been very helpful.

Notes
 
³ To whom correspondence should be addressed. Fax: +44 1382 344275. E-mail: [email protected]