Effect of Thallium(I) on Growth, Nutrient Absorption, Photosynthetic Pigments, and Antioxidant Response of Dittrichia Plants

Abstract

Dittrichia plants were exposed to thallium (Tl) stress (10, 50, and 100 µM) for 7 days. The Tl toxicity altered the absorption and accumulation of other nutrients. In both the roots and the leaves, there was a decline in K, Mg, and Fe content, but an increase in Ca, Mn, and Zn. Chlorophylls decreased, as did the photosynthetic efficiency, while carotenoids increased. Oxidative stress in the roots was reflected in increased lipid peroxidation. There was more production of superoxide (O2.−), hydrogen peroxide (H2O2), and nitric oxide (NO) in the roots than in the leaves, with increases in both organs in response to Tl toxicity, except for O2.− production in the roots, which fluctuated. There was increased hydrogen sulfide (H2S) production, especially in the leaves. Superoxide dismutase (SOD), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), and glutathione reductase (GR) showed increased activities, except for APX and MDHAR in the roots and GR in the leaves. The components of the ascorbate–glutathione cycle were affected. Thus, ascorbate (AsA) increased, while dehydroascorbate (DHA), reduced glutathione (GSH), and oxidized glutathione (GSSG) decreased, except for in the roots at 100 µM Tl, which showed increased GSH. These Tl toxicity-induced alterations modify the AsA/DHA and GSH/GSSG redox status. The NO and H2S interaction may act by activating the antioxidant system. The effects of Tl could be related to its strong affinity for binding with -SH groups, thus altering the functionality of proteins and the cellular redox state.

Dittrichia viscosa Selection Strategy Based on Stress Produces Stable Clonal Lines for Phytoremediation Applications

“…The different ROS-scavenging enzymes in plants, such as CAT, SOD and GSH reductase (GR), increase in parallel [10,26]. In a recent study [27] in which Dittrichia is challenged with Thallium(I), the authors showed that APX activity in leaves was just slightly increased by increasing concentrations of the HM, with a resulting H 2 O 2 concentration increment suggesting a weak increase in CAT activity. Also, GR activity did not change with the increasing concentration of HM.…”

Effects of Cadmium, Thallium, and Vanadium on Photosynthetic Parameters of Three Chili Pepper (Capsicum annuum L.) Varieties

“…According to the in-depth search in the scientific literature, there is no previously published information to compare the effects of Cd, Tl and V on the photosynthetic parameters of three chili pepper varieties. However, several studies have documented the individual effects of these elements on plant physiology and metabolism, including photosynthesis [63][64][65].…”

Mechanisms of Uptake and Translocation of Thallium in Brassica Vegetables: An X-ray Fluorescence Microspectroscopic Investigation

“…14 In Dittrichia plants exposed to 100 μM Tl, oxidative stress was observed as well as a decline of some nutrients (Fe, Mg, and K). 15 A study on Sinapsis alba (white mustard) showed that Tl tolerance decreased in higher Tl treatments, with evident effects on growth inhibition, oxidation of pigments, and a decline in photosystem core proteins. 16 Of all the nonessential trace elements, Tl has some of the highest bioaccumulation coefficients among plants, with high values reported in members of the Brassicaceae family.…”

“…A recent study on Arabidopsis thaliana reported that Tl interferes in K-dependent processes, inhibits photosynthetic activity, and enhances oxidative stress . In Dittrichia plants exposed to 100 μM Tl, oxidative stress was observed as well as a decline of some nutrients (Fe, Mg, and K) . A study on Sinapsis alba (white mustard) showed that Tl tolerance decreased in higher Tl treatments, with evident effects on growth inhibition, oxidation of pigments, and a decline in photosystem core proteins .…”