PLANT PHYSIOLOGY , Vol 107, Issue 4 1371-1377, Copyright © 1995 by American Society of Plant Biologists
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WHOLE PLANT, ENVIRONMENTAL, AND STRESS PHYSIOLOGY |
Investigation of Local Ethylene Emission from Intact Cherry Tomatoes by Means of Photothermal Deflection and Photoacoustic Detection
HSM. de Vries, FJM. Harren, LACJ. Voesenek, CWPM. Blom, E. J. Woltering, HCPM. van der Valk and J. Reuss
Department of Molecular and Laser Physics, (H.S.M.V., F.J.M.H., J.R.) and Department of Ecology (L.A.C.J.V., C.W.P.M.B.), University of Nijmegen, Toernooiveld, 6525ED Nijmegen, The Netherlands
The function of the coronet region of the cherry tomato (Lycopersicon
esculentum Cherry) as the main emission channel for ethylene was
investigated. Ethylene was measured employing two laser-based detection
systems, the photothermal deflection instrument and the photoacoustic
detection setup. It is possible to detect minimum ethylene concentrations
of 1 nL L-1 locally and rapidly with the first instrument and
concentrations of 6 pL L-1 in a continuous flow system with the second
setup. The continuous flow system makes it possible to change the air
composition and to monitor its influence on the ethylene production of the
tomato. The response times of the two instruments are 30 s and 4 min,
respectively. The local character of the measurements makes it possible to
determine the emission sites of the gaseous plant hormone ethylene and
their relative importance. Transient anoxic conditions stop production of
ethylene; return to aerobic conditions shows the evolution of the
accumulated ethylene precursor 1-aminocyclopropane-1-carboxylic acid and
its renewed production on the measured ethylene emission, with a time
resolution of several minutes. Temporarily sealing the main emission
channel yields results comparable to anoxia.