Altered xanthophyll cycle and fluorescence quenching indicate light-dependent early events in paraquat-treated resistant Erigeron canadensis

Váradi, Gyula: Altered xanthophyll cycle and fluorescence quenching indicate light-dependent early events in paraquat-treated resistant Erigeron canadensis. Acta biologica Szegediensis, (46) 3-4. pp. 157-158. (2002)

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Abstract

Violaxanthin de-epoxidation and chlorophyll fluorescence quenching in the presence of paraquat (Pq ) were studied in intact attached leaves of Pq-susceptible (PqS) and Pq-resistan t (PqR) biotypes of Erigeron canadensis under different light conditions. Initially, similar changes were induced in the two biotypes, but the effects relaxed only in the PqR plants, indicating a Pq elimination process. The penetration of Pq in of the chloroplasts of PqR plants proved to be somewhat restricted and highly light-dependent, as revealed by both the light response curves of violaxanthin de-epoxidation and fluorescence quenching and the short-term high-light pre-illumination experiments. An irregular down-regulation of the nonphotochemical fluorescence quenching (NPQ) processes was observed, reflected by lower steady-state zeaxanthin and NP Q levels as compared with the corresponding non-treated high-light controls. It is concluded that light is essential not only forthe initiation of the mechanism of resistance to Pq, but also for the penetration of Pq into the chloroplasts in the PqR E. canadensis. Also, the Pq elimination process may cause a modification to the regulation of the non-radiative energy dissipation in PqR plants in the presence of Pq.

Item Type: Article
Event Title: Hungarian Congress on Plant Physiology, 7., 2002, Szeged
Journal or Publication Title: Acta biologica Szegediensis
Date: 2002
Volume: 46
Number: 3-4
Page Range: pp. 157-158
ISSN: 1588-385X
Language: angol
Heading title: Photosynthesis, the effects of UV-B irradiation; Proceedings of the 7th Hungarian Congress on Plant Physiology
Uncontrolled Keywords: Természettudomány, Biológia
Additional Information: Bibliogr.: 158. p.; Abstract
Date Deposited: 2016. Oct. 17. 09:25
Last Modified: 2018. May. 28. 11:29
URI: http://acta.bibl.u-szeged.hu/id/eprint/22542

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