Plant and Soil

, Volume 248, Issue 1, pp 21–30

The evolution of physiology and development in the cluster root: teaching an old dog new tricks?

  • Keith R. Skene

DOI: 10.1023/A:1022303201862

Cite this article as:
Skene, K.R. Plant and Soil (2003) 248: 21. doi:10.1023/A:1022303201862


In this paper we examine the key elements of cluster or proteoid roots, and trace their origins back to regular root properties. By viewing the root system as being composed of two categories of surface, the high transport capacity (HTC) area, just behind the meristem, and the low transport capacity (LTC) area (the rest of the root system), based on export and import capacities, we examine root system architecture in terms of structure–function relationships, and conclude that measuring total root exudation per unit area, volume or mass will not give useful comparative data for root transport properties. Furthermore, the cluster root represents a manipulation of the HTC to LTC root surface area ratio. Increased exudation and P uptake may be no higher in individual rootlets than in other HTC regions of the root system. We also examine the transformation theory (the theory of form resulting from a series of forces, which, when altered, lead to a change, or transformation in form) as an explanation of cluster root evolution, and conclude that the cluster root requires only a change in pericycle response to depleted internal nutrient levels, with the other characteristics representing consequences stemming from the form and constraints of the root system.

cluster roots high transport capacity (HTC) low transport capacity (LTC) morphogenesis proteoid roots pseudo-cluster root root architecture transformation theory 

Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • Keith R. Skene
    • 1
  1. 1.Division of Environmental and Applied Biology, Institute of Biological SciencesUniversity of DundeeDundeeScotland

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