Plant and Soil

, Volume 219, Issue 1–2, pp 221–229

A comparison of the effects of auxin on cluster root initiation and development in Grevillea robusta Cunn. ex R. Br. (Proteaceae) and in the genus Lupinus (Leguminosae)

  • Keith R. Skene
  • Wendy M. James

DOI: 10.1023/A:1004730118886

Cite this article as:
Skene, K.R. & James, W.M. Plant and Soil (2000) 219: 221. doi:10.1023/A:1004730118886


The effect of NAA (naphthaleneacetic acid) on the development of cluster roots in members of the Proteaceae and Leguminosae was investigated. The exogenous addition of NAA led to initiation of cluster roots in phosphate conditions normally inhibitory for their development, but initiation took place within the limits of the cluster pattern under −P conditions. There was no change in spacing within the cluster root nor between cluster roots in Grevillea robusta Cunn. ex R. Br. or in rootlet length or cluster root length. In Lupinus albus L., change in rootlet length and cluster root length was noted at 10-10 and 1012M NAA. In L. albus, the length of time that roots were exposed to NAA does not appear to be important, with similar levels of cluster root initiation after 48 h and 7 days. Cluster root production in G. robusta differed from that in L. albus in terms of the concentration of NAA needed to induce initiation, and in the effects of extremely low levels of NAA on rootlet numbers and lengths. L. arboreus L. does not produce cluster roots under −P conditions. Furthermore, neither L. arboreus L., L. angustifolius L., L. luteus L. nor L. mutabilis L. were induced to produce cluster roots under −P conditions, nor under +P conditions in the presence of exogenous NAA. Thus, exogenous NAA only leads to the induction of cluster roots, at levels of P normally inhibitive of their development, in species of Lupinus that produce them under −P conditions. Auxin-induced cluster roots develop within the same constraints as those developing under −P conditions. NAA does not induce cluster roots in species of Lupinus that do not produce them under −P conditions.

auxin cluster roots proteoid roots root development root initiation 

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • Keith R. Skene
  • Wendy M. James

There are no affiliations available

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