An off-line implementation of the stable isotope technique for measurements of alternative respiratory pathway activities

Nagel, O.W., Waldron, S. and Jones, H.G. (2001) An off-line implementation of the stable isotope technique for measurements of alternative respiratory pathway activities. Plant Physiology, 127(3), pp. 1279-1286.



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In situ measurements of alternative respiratory pathway activity are needed to provide insight into the energy efficiency of plant metabolism under various conditions in the field. The only reliable method at present to measure alternative oxidase (AOX) activity is through measurement of changes in delta O-18(O-2), which to date has only been used in laboratory environments. We have developed a cuvette system to measure partitioning of electrons to AOX that is suitable for off-line use and for field experiments. Plant samples are enclosed in airtight cuvettes and O-2 consumption is monitored. Gas samples from the cuvette are stored in evacuated gas containers until measurement of delta O-18(O-2). We have validated this method using differing plant material to assess AOX activity. Fractionation factors were calculated from delta O-18(O-2) measurements, which could be measured with an accuracy and precision to 0.1 parts per thousand and 0.3 parts per thousand respectively. Potential sources of error are discussed and quantified. Our method provides results similar to those obtained with laboratory incubations on-line to a mass spectrometer but greatly increases the potential for adoption of the stable isotope method.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Waldron, Professor Susan
Authors: Nagel, O.W., Waldron, S., and Jones, H.G.
Subjects:Q Science > QK Botany
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Plant Physiology
Publisher:American Society of Plant Biologists
Copyright Holders:© American Society of Plant Biologists.
First Published:First published in Plant Physiology 127(3):1279-1286
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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