'Radicle' biochemistry: the biology of root-specific metabolism

The roots of higher plants are a fascinating and largely unexplored biologi cal frontier. One of their features is the ability to synthesize a remarkab le diversity of secondary metabolites, and to adjust their metabolic activi ties in response to biotic and abiotic stress. This includes the ability to exude a complex array of micro- and macromolecules into the, rhizosphere, with the potential to affect the inter-relationships between plants and ben eficial or deleterious soil-borne organisms. In the past, research on root biology has been hampered by the underground growth habit of roots and by t he lack of a suitable experimental system. However, recent progess in growi ng roots in isolation has greatly facilitated the study of root-specific me tabolism and contributed to our understanding of this remarkable plant orga n.