Effect of Selenium on Alleviating Oxidative Stress Caused by a Water Deficit in Cucumber Roots.

Jóźwiak Jóźwiak,Politycka Politycka

doi:10.3390/plants8070217

Jóźwiak Jóźwiak, Politycka Politycka

Open Access

https://doi.org/10.3390/plants8070217

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Abstract

The aim of the study was to evaluate the antioxidant activity of selenium in the roots of Cucumis sativus L. seedlings pre-treated with selenium (Se) in the form of sodium selenite at concentrations of 1, 5, and 10 µM, and then subjected to a water deficit (WD). It has been hypothesized that Se, in low concentrations, alleviates an oxidative stress caused by a WD in the cucumber roots. A WD was introduced by the surface dehydration of roots. The aim of the research was to compare the changes accompanying oxidative stress in plants growing in the presence of Se and in its absence. The study concerns the generation of reactive oxygen species (ROS)—superoxide anions (O2•−), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH)—as well the activities of the antioxidant enzymes lowering the ROS level—ascorbate peroxidase (APX), peroxidase (POX), catalase (CAT), and superoxide dismutase (SOD). A WD caused oxidative stress, i.e., the enhanced generation of ROS. Selenium at the concentrations of 1 and 5 μM increased the tolerance of cucumber seedlings to oxidative stress caused by a WD by increasing the activities of the antioxidant enzymes, and it also limited the damage of plasma membranes as a result of the inhibition of lipid peroxidation.

Highlights

Plant metabolism is often disrupted by a number of adverse environmental factors; it is important to conduct research towards the increasing ability of plants to survive in these unfavourable conditions
Selenium at the concentrations of 1 and 5 μM increased the tolerance of cucumber seedlings to oxidative stress caused by a water deficit (WD) by increasing the activities of the antioxidant enzymes, and it limited the damage of plasma membranes as a result of the inhibition of lipid peroxidation
It was found that the pre-treatment of cucumber seedlings with Se at different concentrations caused a significant increase in the generation of O2 − only at the highest Se concentration (10 μM), compared to the control that did Plants 2018, 7, x FOR PEER REVIEW

Summary

Introduction

Plant metabolism is often disrupted by a number of adverse environmental factors; it is important to conduct research towards the increasing ability of plants to survive in these unfavourable conditions. Drought is one of the main factors limiting crop yielding. About 45% of the world crop area is exposed to continuous or frequent drought stress, and over 40% of world-wide yields, especially vegetables, are obtained on artificially irrigated soils [1]. High water requirements are one of the reasons for restricted cucumber cultivation. This species is extremely sensitive to a water deficit (WD) [2,3], which is associated with a poorly developed and shallow root system, the production of a large mass of above-ground parts, and a high water content in fruits. Low soil moisture reduces the size and quality of a cucumber yield [4]

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