Root elongation rate is correlated with the length of the bare root apex of maize and lupin roots despite contrasting responses of root growth to compact and dry soils

Sonja Schmidt, Peter J. Gregory, Dmitri V. Grinev, A. Glyn Bengough

Research output: Contribution to journalArticle

7 Citations (Scopus)


BackgroundWe investigated interacting effects of matric potential and soil strength on root elongation of maize and lupin, and relations between root elongation rates and the length of bare (hairless) root apex.

MethodsRoot elongation rates and the length of bare root apex were determined for maize and lupin seedlings in sandy loam soil of various matric potentials (−0.01 to −1.6 MPa) and bulk densities (0.9 to 1.5 Mg m−3).

ResultsRoot elongation rates slowed with both decreasing matric potential and increasing penetrometer resistance. Root elongation of maize slowed to 10 % of the unimpeded rate when penetrometer resistance increased to 2 MPa, whereas lupin elongated at about 40 % of the unimpeded rate. Maize root elongation rate was more sensitive to changes in matric potential in loosely packed soil (penetrometer resistances <1 MPa) than lupin. Despite these differing responses, root elongation rate of both species was linearly correlated with length of the bare root apex (r2 0.69 to 0.97).
ConclusionMaize root elongation was more sensitive to changes in matric potential and mechanical impedance than lupin. Robust linear relationships between elongation rate and length of bare apex suggest good potential for estimating root elongation rates for excavated roots.
Original languageEnglish
Pages (from-to)609-618
Number of pages10
JournalPlant and Soil
Issue number1-2
Early online date26 May 2013
Publication statusPublished - Nov 2013


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