Effect of different forms of selenium on the plant–soil–earthworm system

Abstract

Selenium (Se) is an essential micronutrient for humans, animals, and certain lower plants, but at higher concentrations Se becomes toxic to organisms. The boundary between the Se beneficial effect and its toxicity is narrow and depends on its chemical form, applied concentration, and other environmentally regulating factors. Due to the potential risk of toxicity in higher concentration, the aim of this study was to estimate the impact of increased concentrations of different forms of Se on the response of the wheat–soil–earthworm system. Soil, earthworms, and wheat grains were exposed to the Se in form of selenite and selenate in concentrations of 0.01, 0.1, and 1 mg kg−1. As an indicator of oxidative stress in wheat, lipid peroxidation levels (LPO) and total H2O2 content were determined, while antioxidative response was determined by catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR) activities. The biomarker responses in earthworms were determined by acetylcholinesterase (AChE), carboxylesterase (CES), and antioxidative enzymes (CAT and glutathione S‐transferase) activities. Selenite and selenate increased Se content in the wheat and earthworms, while selenate application was more efficient, indicating higher bioaccumulation of this Se form. Both Se forms did not cause significant changes in the LPO level and H2O2 content, while GPX activities were elevated in all treatments, suggesting that oxidative stress was not induced in wheat. In earthworms, Se significantly reduced activities of AChE and CAT at some concentrations, while CES activity was increased at all concentrations applied. This study showed significant impact of Se on measured biochemical responses in wheat and earthworms, indicating the disruption of homeostasis. Obtained results can serve as basis for further studies on Se effects and will help in including different aspects necessary for understanding of Se impact on different components of soil ecosystems.

Nutritive Evaluation of Earthworms as Human Food

“…Due to the assimilation of metals from their environment, earthworms often contain elevated levels of metals, including some heavy metals that could be harmful to animals and human beings [40,41]. However, in experiments with ish and chicken, no signiicant increases in heavy metals was found in the carcasses of the trial animals fed on earthworms.…”

Effects of Selenium on Serotonin Synthesis and the Glutathione Redox Cycle in Plum Leaves

“…The Se-mediated regulation of GPX has been reported previously in animals (Carmagnol et al 1983;Lei et al 1995), but the existence of essential Se-dependent proteins has not been demonstrated in higher plants (Stolfa et al 2017). A correlation between the Se concentration and GPX activity was reported in wheat (Stolfa et al 2017), ryegrass (Cartes et al 2005), Chinese cabbage (Wu et al 2017), and potato (Seppanen et al 2003). Moreover, Se is also post-translationally assimilated into Cys-38 of the non-Se-dependent GPX to enhance its enzymatic activity in algae (Takeda, 2015).…”

The Toxic Effects of Sulfoxaflor Induced in Earthworms (Eisenia fetida) under Effective Concentrations

“…The TBARS, mainly malonaldehyde (MDA), is an important indicator to reflect the level of lipid peroxidation and is determined by monitoring the reaction between MDA and thiobarbituric acid (TBA) [25]. After heating at 95 • C in a water bath for 1 h, the absorbance of the red reaction product was detected at 532 nm [26].…”

“…Therefore, we can deduce that sulfoxaflor can cause cytotoxicity to earthworms. TBARS were cytotoxic final products of cell lipid peroxidation; content could reflect whether the body is subjected to lipid peroxidation [25,41,42]. Moreover, the TBARS content could illuminate whether external pressure causes cell damage [30,35].…”