New Zealand Journal of Agricultural Research abstracts
An experimental method for varying root temperature independently of shoot temperature
M. L. Castle1,2
J. R. Crush1,*
J. S. Rowarth2,†
1AgResearch
Ruakura Research Centre
Private Bag 3123
Hamilton, New Zealand
jim.crush@agresearch.co.nz
2Unitec
Private Bag 92 025
Auckland, New Zealand
*Author for correspondence.
†Present address: University of Melbourne, Victoria 3010, Australia.
Abstract In the field, roots and shoots of plants
are seldom exposed to the same temperature. Methods for varying root
temperature independently of shoot temperature have relied upon
hydroponic systems or field-based studies, and both approaches have
limitations for investigating the physiological affects of temperature
on nutrient uptake. A low-cost method for varying root and shoot
temperature independently using a solid root medium was developed, and
its utility demonstrated in an experiment with white clover. The
“temperature gradient trough” enabled the effects of a
range of root temperatures from 6 to 24°C on nitrogen (N) uptake
and distribution to be evaluated. Results showed that at an 8°C
shoot temperature, an increase in root temperature resulted in an
increase in 15N distribution to the laminae. At a 24°C
shoot temperature, and root temperatures greater than 10°C, plants
had significantly more 15N in laminae and petioles than at
shoot temperatures of 8°C. The temperature gradient trough enabled
independent varying of root and shoot temperatures in a controlled
environment, allowing rapid exploration of the effects of temperature
on N distribution in white clover.
Keywords nitrogen; root temperature; temperature gradient; white clover
A05037; Received 13 September 2005; accepted 10 January 2006; Online publication date 9 May 2006
New Zealand Journal of Agricultural Research, 2006, Vol. 49: 157–162
0028–8233/06/4902–0157 © The Royal Society of New Zealand 2006
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