Selenium Improves Physiological Parameters and Alleviates Oxidative Stress in Shoots of Lead-Exposed Vicia faba L. minor Plants Grown Under Phosphorus-Deficient Conditions

Magdalena Mroczek-Zdyrska,Agnieszka Hanaka,Joanna Strubińska

doi:10.1007/s00344-016-9629-7

Magdalena Mroczek-Zdyrska, Agnieszka Hanaka + Show 1 more

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https://doi.org/10.1007/s00344-016-9629-7

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Abstract

The goal of the study was to investigate the effects of exogenous selenium (Se) on the tolerance of faba bean plants to lead (Pb) stress under P-deficient conditions. The bean plants were grown for 2 weeks on Hoagland solution supplied with Pb (0, 50 μM) and Se (0, 1.5, or 6 μM), separately or simultaneously. It was shown that Pb did not affect shoot growth but caused major damage in the leaves, which was accompanied by Pb accumulation in these tissues. The exposure of the shoots to Pb led to significant changes in the biochemical parameters: the MDA content, glutathione peroxidase (GSH-Px), guaiacol peroxidase (GPOX), and catalase (CAT) activity increased. Furthermore, Pb intensified O2•− and H2O2 production. Both the Se concentrations used increased the chlorophyll b, chlorophyll a+b, and carotenoid content in the faba bean plants. Selenite also generally enhanced CAT, GPOX, and GSH-Px activities and the T-SH level. Our results imply that the degree of disturbances caused by Pb could be partially ameliorated by Se supplementation. Selenite at a lower dose alleviated Pb toxicity by decreased H2O2 and O2•− production and decreased the GSH-Px, GPOX, and CAT activities. The beneficial effect of the higher selenite concentration could be related to reduction of lipid peroxidation in the shoots of the Pb-treated plants. However, the effect of Se on the Pb-stressed plants greatly depended on the selenite dose in the nutrient solution.

Highlights

Plants are able to absorb and accumulate diverse types of metals, from toxic to those with unknown metabolic functions
The goal of the study was to investigate the effects of exogenous selenium (Se) on the tolerance of faba bean plants to lead (Pb) stress under P-deficient conditions
Se is a known anticarcinogen and antioxidant compound, which recently is quite frequently supplied in fertilizers to improve its deficiency in soil or to enrich plants and food crops in Se, having ameliorating advantages in food characteristics, like the shelf life (D’Amato and others 2014)

Summary

Introduction

Plants are able to absorb and accumulate diverse types of metals, from toxic to those with unknown metabolic functions. Heavy metals present in the environment in excess are dangerous for human and animal health. Pb accumulation in plant tissues results in numerous disturbances of physiological processes such as alterations in cell membrane permeability, water stress, disturbances in cell division, or inhibition of the electron transport during photosynthesis and respiration (Sengar and others 2008). To overcome the effect of Pb stress, plants can effectively scavenge oxygen species: H2O2, OH, and O2-. Both enzymatic (catalases and peroxidases) and non-enzymatic antioxidants (GSH, AsA, and car) are involved in this process (Verma and Dubey 2003)

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