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Alternative respiration and heat evolution in plants.

Authors
  • Ordentlich, A
  • Linzer, R A
  • Raskin, I
Type
Published Article
Journal
PLANT PHYSIOLOGY
Publisher
American Society of Plant Biologists
Publication Date
Dec 01, 1991
Volume
97
Issue
4
Pages
1545–1550
Identifiers
PMID: 16668582
Source
Medline
License
Unknown

Abstract

The alternative respiratory pathway dissipates most of the chemical energy of respiratory substrates as heat. We have shown that this heat can be quantified by microcalorimetry and is a measure of alternative pathway activity in vivo. The alternative pathway is known to increase in aged potato (Solanum tuberosum) slices and in chill-stressed leaves. Aging of potato slices for 24 hours was accompanied by an almost fourfold increase in the rate of heat evolution. This heat increase was resistant to KCN but could be blocked by an alternative pathway inhibitor, salicylhydroxamic acid (SHAM). In cucumber (Cucumis sativus) leaves subjected to chilling stress (between 4 and 16 degrees C), the rate of heat evolution was inversely related to temperature. As in aged potato slices, the increased rate of heat evolution in cucumber leaves was blocked by SHAM, but not by KCN. Nitrogen or the combination of SHAM and KCN blocked most of the heat evolution in both aged potato slices and chill-stressed cucumber leaves. Calorimetric measurements of the alternative pathway corresponded to respiration measurements performed using an oxygen electrode.

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