Abstract
Two experiments were performed in simplified soil-less systems to study how roots respond to changes in mechanical impedance. In the first the increases in root force and diameter that occur when a pea root was impeded mechanically inside a hole with rigid conical walls were determined. The experiment was performed at 8°C and at 25°C, and the root growth pressures generated were calculated during periods of 12, 24, 48 and 72 hours. The maximum growth pressures generated were approximately the same at both temperatures, although the maximum pressure was achieved approximately twice as quickly at 25°C than at 8°C, being reached within 15–20 hours. In the second set of experiments a new technique was developed to measure simultaneously the elongation rate and the force exerted by the roots of seedlings grown in moist air. A constant force was exerted by a force transducer on a pea radicle using a system of pulleys, and the elongation rate of the pea root was monitored using a linear variable differential transformer (LVDT). The changes in root elongation rate were recorded that occurred in response to increases and decreases in the applied force. Root elongation rate decreased by more than 50% within 30 min of increasing the applied force by 100 mN. A similarly fast, but smaller increase in growth rate occurred when the force was removed. The interpretation of results from both studies will be discussed in terms of a modified form of the Lockhart model of growth.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Abdalla A M, Hettiaratchi D R P and Reece A R 1969 The mechanics of root growth in granular media. J. Agric. Eng. Res. 14, 263–248.
Atwell B J 1990 The effect of soil compaction on wheat during early tillering. II. Concentrations of cell constituents. New Phytol. 115, 37–41.
Barlow P W 1993 The response of roots and root systems to their environment–an interpretation derived from an analysis of the hierarchical organization of plant life. Env. Exp. Bot. 33, 1–10.
Bengough A G and Mullins C E 1990 Mechanical resistance to root growth: A review of experimental techniques and root growth responses. J. Soil Sci. 41, 341–358.
Bengough A G and Young I M 1993 Root elongation of seedling peas through layered soil of different penetration resistances. Plant and Soil 149, 129–139.
Bengough A G and MacKenzie C J 1994 Simultaneous measurement of root force and elongation for seedling pea roots. J. Exp. Bot. 45, 95–102.
Eavis B W, Ratliff L F and Taylor H M 1969 Use of a deadload technique to determine axial root growth pressure. Agron. J. 61, 640–643.
Goss M J and Russell R S 1980 Effects of mechanical impedance on root growth in barley (Hordeum vulgare L.). III. Observations on the mechanism of response. J. Exp. Bot. 31, 577–588.
Greacen E L 1986 Root response to soil mechanical properties. Trans.13th Int. Congr. Soil Sci. 5, 20–47.
Greacen E L and Oh J S 1972 The physics of root growth. Nature, New Biol. 235, 24–25.
Misra R K, Dexter A R and Alston A M 1986 Maximum axial and radial growth pressures of plant roots. Plant and Soil 95, 315–326.
Passioura J B and Fry S C 1992 Turgor and cell expansion: Beyond the Lockhart Equation. Aust. J. Plant Phys. 19, 565–576.
Pritchard J, Barlow P W, Adam J S and Tomos A D 1990a Biophysics of the inhibition of the growth of maize roots by lowered temperature. Plant Physiol. 93, 222–230
Pritchard J, Wyn Jones R G and Tomos A D 1990b Measurement of yield threshold and cell wall extensibility of intact wheat roots under different ionic, osmotic and temperature treatments. J. Exp. Bot. 41, 669–675.
Taylor H M and Ratliff L F 1969 Root growth pressures of cotton, peas, and peanuts. Agron. J. 61, 398–402.
Veen B W 1982 The influence of mechanical impedance on the growth of maize roots. Plant and Soil 66, 101–109.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1995 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Bengough, A.G., Mackenzie, C.J., Elangwe, H.E. (1995). Biophysics of the growth responses of pea roots to changes in penetration resistance. In: Baluška, F., Čiamporová, M., Gašparíková, O., Barlow, P.W. (eds) Structure and Function of Roots. Developments in Plant and Soil Sciences, vol 58. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-3101-0_37
Download citation
DOI: https://doi.org/10.1007/978-94-017-3101-0_37
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-4402-0
Online ISBN: 978-94-017-3101-0
eBook Packages: Springer Book Archive