Vidović Marija, Morina Filis, Prokić Ljiljana, Milić-Komić Sonja, Živanović Bojana, Jovanović Sonja Veljović
Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia.
Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080 Belgrade, Serbia.
J Plant Physiol. 2016 Nov 1;206:25-39. doi: 10.1016/j.jplph.2016.07.017. Epub 2016 Sep 1.
In this study we exposed variegated leaves of Pelargonium zonale to strong sunlight (>1100μmolms of photosynthetically active radiation) with and without paraquat (Pq), with the aim to elucidate the mechanisms of HO regulation in green and white tissues with respect to the photosynthetically-dependent generation of reactive oxygen species (ROS). Sunlight induced marked accumulation of HO 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, HO 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 HO in signaling were discussed.
在本研究中，我们将天竺葵的杂色叶片置于强光（光合有效辐射>1100μmol m⁻² s⁻¹）下，分别添加和不添加百草枯（Pq），旨在阐明绿色和白色组织中过氧化氢（HO）调节机制与光合作用依赖的活性氧（ROS）生成之间的关系。阳光仅在绿色区域诱导HO在维管组织和（周）维管组织的质外体中显著积累。添加Pq可增强这种效应。在存在二苯基碘化物（一种NADPH氧化酶抑制剂）的情况下，HO积累被消除。观察到明显的光诱导反应：在光合细胞中，阳光迅速引发抗坏血酸（Asc）生物合成以及谷胱甘肽还原酶（GR）和过氧化氢酶活性增加，而在非光合细胞中，观察到可溶性抗坏血酸过氧化物酶、脱氢抗坏血酸还原酶（DHAR）和GR活性早期上调。添加百草枯刺激了绿色区域的DHAR和GR活性，而在白色区域，单脱氢抗坏血酸还原酶、DHAR和Ⅲ类过氧化物酶的活性以及Asc含量迅速增加。讨论了两种组织在其不同代谢框架下的差异抗氧化反应以及（周）维管组织中HO在信号传导中的可能作用。
