1. Lead induces oxidative stress in Pisum sativum plants and changes the levels of phytohormones with antioxidant role.
- Author
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Dias, Maria Celeste, Mariz-Ponte, Nuno, and Santos, Conceição
- Subjects
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PEAS , *OXIDATIVE stress , *LEAD toxicology , *GLUTATHIONE reductase , *INDOLEACETIC acid , *ABSCISIC acid - Abstract
Abstract The interaction of lead (Pb) with plant hormonal balance and oxidative stress remains under discussion. To evaluate how Pb induces oxidative stress, and modulates the antioxidant enzymes and the phytohormones pool, four-week old Pisum sativum plants were exposed during 28 days to 10, 100 and 500 mg kg−1 Pb in soil. In comparison to leaves, roots showed higher Pb accumulation, oxidative damages and changes in phytohormone pools. Contrarily to leaves, where glutathione reductase (GR) and ascorbate peroxidase (APX) activities were more stimulated than catalase (CAT) and superoxide dismutase (SOD), roots showed a stimulation of SOD, GR and APX in all doses, and of CAT in the highest dose. While protein oxidation occurred in roots even at lower Pb-doses, lipid peroxidation and membrane permeability also occurred but at 500 mg kg−1 and in both organs, accompanied by increases of H 2 O 2. Jasmonic acid (JA) responded in both organs even at lowest Pb-doses, while salicylic acid (SA) and abscisic acid (ABA, only in leaves), increased particularly at the concentration of 500 mg Pb kg−1. In conclusion, and compared with leaves, roots showed oxidative damage even at 10 mg Pb Kg−1, being proteins a first oxidative-target, although there is a stimulation of the antioxidant enzymes. Also, JA is mobilized prior to oxidative stress changes are detected, and may play a protective role (activating antioxidant enzymes), while the mobilization of SA is particularly relevant in cells expressing oxidative damage. Other hormones, like indolacetic acid and ABA may have a low protective role against Pb toxicity. Graphical abstract Image 1 Highlights • Oxidative stress and hormonal changes in response to Pb are more evident in roots. • JA responds to low/moderate Pb-doses, while SA and ABA respond to higher doses. • JA correlates with antioxidant enzymes, having a preventive role against ROS damage. • SA antioxidant role is more relevant when plants show some oxidative damages. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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