An efficient antioxidant system and heavy metal exclusion from leaves make Solanum cheesmaniae more tolerant to Cu than its cultivated counterpart

Copper (Cu) is an abundant metal in the environment coming from anthropogenic activities and natural sources that, in excess, easily becomes phytotoxic to most species, being its accumulation in plants considered an environmental threat. This study aimed to compare the physiological and molecular responses of Solanum lycopersicum and its wild counterpart Solanum cheesmaniae to Cu stress. In particular, we wanted to address the hypothesis that S. cheesmaniae is more adapted to Cu stress than S. lycopersicum, since the former is equipped with a more efficient antioxidant defense system than the latter. Biomarkers of oxidative status (lipid peroxidation, hydrogen peroxide (H2O2) and superoxide anion (O.− 2 ) levels) revealed a more pronounced imbalance in the redox homeostasis in shoots of S. lycopersicum than in S. cheesmaniae in response to Cu. Furthermore, the activity of key antioxidant enzymes clearly differed in both species in response to Cu. Catalase (CAT) activity increased in S. cheesmaniae shoots but decreased in the domestic species, as well as ascorbate peroxidase (APX). Both species preferentially accumulated Cu in the radicular system, although a great increase in the aerial parts of S. lycopersicum was measured, while in leaves of Cu- treated S. cheesmaniae, the levels of Cu were not changed. Overall, results validated the hypothesis that S. cheesmaniae is more tolerant to excess Cu than S. lycopersicum and the data provided will help the development of breeding strategies toward the improvement of the resistance/tolerance of cultivated tomato species to heavy metal stress.This research was partially supported by national funds provided by Foundation for Science and Technology (FCT) through PEst-OE/BIA/UI4046/2014 (FCT through BioISI) and through the research project PTDC/ AGR-PRO/7028/2014.info:eu-repo/semantics/publishedVersio

Accumulation potential of Atriplex halimus to zinc and lead combined with NaCl: Effects on physiological parameters and antioxidant enzymes activities

An experiment in this study was designed to investigate the effect of different concentrations of Zn2+ or Pb2+ (0, 200, 400 and 600 μM) with NaCl (0, 200 mM), on the morphological and physiological parameters as well as the antioxidative response of the halophytic species Atriplex halimus. Results showed that Pb2+ had no significant impact on biomass production while Zn2+ significantly affected plant development mainly at high concentration, 600 μM. Total chlorophyll content did not change significantly under elevation concentrations of Zn2+ when compared to control. However, there was a modest decrease in total chlorophyll concentration in the leaves of A. halimus grown in a medium supplemented with 600 μMPb2+ and with combined stress Pb2+/NaCl. Zn2+ and Pb2+ contents in tissues were higher in the belowground organs of this halophyte. Overall results pointed out that application of different concentrations of Zn2+ or Pb2+ disturbed status of nutrients in A. halimus. Analysis of antioxidant enzymes [ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT)] showed that the activity was diminished by increasing Zn2+ concentrations in the medium. Whereas, the addition of Pb2+ in the medium increased CAT activity and decreased APX activity.info:eu-repo/semantics/publishedVersio

Physiological and biochemical responses of Suaeda fruticosa to cadmium and copper stresses: growth, nutrient uptake, antioxidant enzymes, phytochelatin, and glutathione levels

Environmental pollution by trace metal elements (TMEs) is a serious problem worldwide, increasing in parallel with the development of human technology. The present research aimed to examine the response of halophytic species Suaeda fruticosa to oxidative stress posed by combined abiotic stresses. Plants have been grown for 1 month with an irrigation solution supplemented with 200 mM NaCl and 400 μM Cd2+ or 400 μM Cu2+. The level of glutathione (GSH), phytochelatins (PCs), and antioxidant enzyme activities [ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT)] as well as lipid peroxidation was studied to see the stress exerted by the TME and the level of tolerance and detoxification strategy adopted by S. fruticosa. Relative growth rate (RGR) decreased under Cd2+ stress in this species, whereas Cu2+ did not have any impact on S. fruticosa performance. Cd2+ or Cu2+ enhanced malondialdehyde, suggesting reactive oxygen species-induced disruption of membrane integrity and oxidative stress in S. fruticosa. On the other hand, the activities of the antioxidant enzymes CAT, APX, and GPX diminished and mineral nutrition was disturbed by metal stress. S. fruticosa was able to synthesize PCs in response to TME toxicity. However, data indicate that GSH levels underwent a significant decrease in roots and leaves of S. fruticosa stressed by Cd2+ or Cu2+. The GSH depletion accompanied by the increase of phytochelatin concentration suggests the involvement of GSH in the synthesis of phytochelatins.info:eu-repo/semantics/publishedVersio