Antioxidative response in variegated Pelargonium zonale leaves and generation of extracellular H₂O₂ in (peri)vascular tissue induced by sunlight and paraquat

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• 作者：Marija Vidović^a ; ^{marija@imsi.rs" class="auth_mail" title="E-mail the corresponding author} ; Filis Morina^a ; ^{filkis14@hotmail.com" class="auth_mail" title="E-mail the corresponding author} ; Ljiljana Prokić^b ; ^{ljprokic@agrif.bg.ac.rs" class="auth_mail" title="E-mail the corresponding author} ; Sonja Milić-Komić^a ; ^{soonjam@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Bojana Živanović^a ; ^{bokazivanovic@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Sonja Veljović Jovanović^a ; ^{sonjavel@imsi.rs" class="auth_mail" title="E-mail the corresponding author}
• 关键词：ABA ; abscisic acid ; APX ; ascorbate peroxidase ; Asc ; reduced ascorbate ; CAT ; catalase ; DAB ; 3 ; 3&prime ; -diaminobenzidine ; DHA ; dehydroascorbate ; DHAR ; dehydroascorbate reductase ; GR ; glutathione reductase ; GSH ; reduced glutathione ; GSSG ; oxidized glutathione ; HPLC ; high-performance liquid chromatography ; MDAR ; monodehydroascorbate reductase ; O2 ; superoxide anion radical ; PAR ; photosynthetically active radiation (400&ndash ; 700  ; nm) ; PODs ; class III peroxidases ; PS ; photosystem ; ROS ; reactive o
• 刊名：Journal of Plant Physiology
• 出版年：2016
• 出版时间：1 November 2016
• 年：2016
• 卷：206
• 期：Complete
• 页码：25-39
• 全文大小：4518 K

文摘

In this study we exposed variegated leaves of Pelargonium zonale to strong sunlight (>1100 μmol m⁻² s⁻¹ of photosynthetically active radiation) with and without paraquat (Pq), with the aim to elucidate the mechanisms of H₂O₂ regulation in green and white tissues with respect to the photosynthetically-dependent generation of reactive oxygen species (ROS). Sunlight induced marked accumulation of H₂O₂ in the apoplast of vascular and (peri)vascular tissues only in green sectors. This effect was enhanced by the addition of Pq. In the presence of diphenyl iodide, an NADPH oxidase inhibitor, H₂O₂ accumulation was abolished. Distinct light-induced responses were observed: in photosynthetic cells, sunlight rapidly provoked ascorbate (Asc) biosynthesis and an increase of glutathione reductase (GR) and catalase activities, while in non-photosynthetic cells, early up-regulation of soluble ascorbate peroxidase, dehydroascorbate reductase (DHAR) and GR activities was observed. Paraquat addition stimulated DHAR and GR activities in green sectors, while in white sectors activities of monodehydroascorbate reductase, DHAR and class III peroxidases, as well as Asc content rapidly increased. Differential antioxidative responses in the two tissues in the frame of their contrasting metabolisms, and the possible role of (peri)vascular H₂O₂ in signaling were discussed.