Increased heat sensitivity of the photosynthetic apparatus in triazine-resistant biotypes from different plant species

Leaf fragments from five species of triazine-resistant and -susceptible plants were exposed for brief periods to temperatures above 38°C. In resistant leaves, a greater increase in temperature-induced fluorescence emission was observed than in susceptible leaves, indicative of greater heat sensitivi...

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Bibliographic Details
Published in:Plant and cell physiology 1985-04, Vol.26 (3), p.419-429
Main Authors: Ducruet, J.M. (Laboratoire des Herbicides-BV, Dijon Cedex (France)), Lemoine, Y
Format: Article
Language:English
Subjects:
AZINAS
AZINE
AZINES
Biological and medical sciences
Chemical control
Fluorescence
FOTOSINTESIS
Fundamental and applied biological sciences. Psychology
Heat-stress
HERBICIDAS
HERBICIDE
HERBICIDES
Life Sciences
Oxygen evolution
Parasitic plants. Weeds
PESTICIDE RESISTANCE
PHOTOSYNTHESE
PHOTOSYNTHESIS
Photosystem II
Phytopathology. Animal pests. Plant and forest protection
PLANTAS
PLANTE
PLANTS
PROPIEDADES TERMICAS
PROPRIETE THERMIQUE
RESISTANCE AUX PESTICIDES
RESISTENCIA A LOS PLAGUICIDAS
THERMAL PROPERTIES
Triazine resistance
VARIEDADES
VARIETE
VARIETIES
Weeds
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Summary:Leaf fragments from five species of triazine-resistant and -susceptible plants were exposed for brief periods to temperatures above 38°C. In resistant leaves, a greater increase in temperature-induced fluorescence emission was observed than in susceptible leaves, indicative of greater heat sensitivity of the PS II electron transfer linked to triazine resistance. The kinetics of fluorescence induction under low or strong light excitation revealed two distinct effects of heat exposure; A DCMU-type inhibition which was reversed upon cooling and a decrease in the variable fluorescence, due mainly to an increase in the constant fluorescence (O level) in resistant leaves, which was only partially reversible. A greater deterioration of electron transfer activity in chloroplasts isolated from resistant plants also was detected, under exposures to a high pH, temperature of 25–35°C and to ferricyanide. This indicates that there is greater instability of the oxygen evolving system in triazine-resistant plants.
ISSN:0032-0781
1471-9053
DOI:10.1093/oxfordjournals.pcp.a076925