Leaf Age-Dependent Photoprotective and Antioxidative Response Mechanisms to Paraquat-Induced Oxidative Stress in Arabidopsis thaliana

International Journal of Molecular Sciences

Julietta Moustaka¹  Georgia Tanou²  Ioannis-Dimosthenis Adamakis¹  Eleftherios P. Eleftheriou¹  Michael Moustakas¹ 

[1]Department of Botany, School of Biology, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece

[2] E-Mails:

[3]Faculty of Agriculture, Forestry and Natural Environment, School of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece

[4] E-Mail:

关键词: antioxidant enzymes;    chlorophyll fluorescence;    differential response;    electron transport;    herbicides;    hydrogen peroxide;    non-photochemical quenching;    reactive oxygen species;   

DOI  :  10.3390/ijms160613989

来源: mdpi

【 摘 要 】

Exposure of Arabidopsis thaliana young and mature leaves to the herbicide paraquat (Pq) resulted in a localized increase of hydrogen peroxide (H₂O₂) in the leaf veins and the neighboring mesophyll cells, but this increase was not similar in the two leaf types. Increased H₂O₂ production was concomitant with closed reaction centers (q_P). Thirty min after Pq exposure despite the induction of the photoprotective mechanism of non-photochemical quenching (NPQ) in mature leaves, H₂O₂ production was lower in young leaves mainly due to the higher increase activity of ascorbate peroxidase (APX). Later, 60 min after Pq exposure, the total antioxidant capacity of young leaves was not sufficient to scavenge the excess reactive oxygen species (ROS) that were formed, and thus, a higher H₂O₂ accumulation in young leaves occurred. The energy allocation of absorbed light in photosystem II (PSII) suggests the existence of a differential photoprotective regulatory mechanism in the two leaf types to the time-course Pq exposure accompanied by differential antioxidant protection mechanisms. It is concluded that tolerance to Pq-induced oxidative stress is related to the redox state of quinone A (Q_A).

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.