An Overview of Selenium Uptake, Metabolism, and Toxicity in Plants

Abstract

Selenium (Se) is an essential micronutrient for humans and animals, but lead to toxicity when taken in excessive amounts. Plants are the main source of dietary Se, but essentiality of Se for plants is still controversial. However, Se at low doses protects the plants from variety of abiotic stresses such as cold, drought, desiccation, and metal stress. In animals, Se acts as an antioxidant and helps in reproduction, immune responses, thyroid hormone metabolism. Selenium is chemically similar to sulfur, hence taken up inside the plants via sulfur transporters present inside root plasma membrane, metabolized via sulfur assimilatory pathway, and volatilized into atmosphere. Selenium induced oxidative stress, distorted protein structure and function, are the main causes of Se toxicity in plants at high doses. Plants can play vital role in overcoming Se deficiency and Se toxicity in different regions of the world, hence, detailed mechanism of Se metabolism inside the plants is necessary for designing effective Se phytoremediation and biofortification strategies.

Selen v vodnih in kopenskih rastlinah / Selenium in water and in terrestrial plants

“…Selenium in the aquatic environment is most commonly a result of anthropogenic factors (Maier & Knight 1994). The accumulation and metabolism of selenium in plants takes place along the sulfur metabolic pathway and usually ends with the conversion of selenium into the volatile substance and its evaporation from the plant (Finley 2005;Gupta & Gupta 2017). The ability of different types of plants to absorb selenium from the soil is also different.…”

“…With its antioxidant action selenium can reduce the production of ethylene in plants and thus slows down the senescence and prolongs the life of the fruits (Lv et al, 2017;Hu et al, 2003;Pezzarossa et al, 2012;Puccinelli et al, 2017). For selenium was found to be able to protect the plants against abiotic stress such as cold, drought and an increased content of heavy metals in the soil and biotic stress such as pathogens and herbivores (Gupta & Gupta 2017;. It should be noted also that the increased concentrations of selenium may also have a negative effect on plants, acting as a pro-oxidant; it can inhibit plant growth and maturation of seeds and reduces the yields of agricultural crops (Hartikainen et al, 2000;Xue et al 2001).…”

“…Selen je po kemijski zgradbi podoben žveplu in tudi privzem selena v rastline poteka preko transporterjev za žveplo, ki se nahajajo v membrani koreninskih celic (Finley 2005;Gupta & Gupta 2017). Rastline privzemajo selen iz tal prvenstveno v obliki selenata, ki se prenese v kloroplaste, njegova asimilacija v rastlini se nato nadaljuje po enaki poti kot asimilacija žvepla.…”

“…Prav tako lahko selen zaščiti rastline pred abiotskim stresom, vključno z ultravijoličnim sevanjem, mrazom, sušo in privzemom težkih kovin iz tal in biotskim stresom, kot so patogeni in herbivori (Gupta & Gupta 2017;. Preuče-vali so, kako dodani selen vpliva na strpnost kumar (Cucumis sativus L.) na kadmij.…”

Effects of Exogenous Selenium Application on the Growth of Sensitive and Tolerant Sorghum Plants Under Salt Stress

“…Selenium (Se) is an essential micronutrient for animals and usually considered a beneficial element for many plant species (Feng et al, 2013;Gupta & Gupta, 2017). Many studies have demonstrated that in low concentrations, Se may acts as a protective agent against several abiotic stresses, such as heavy metals (Chauhan et al, 2017), UV radiation (Golob et al, 2017), drought (Nawaz et al 2016), high temperatures (Djanaguiraman et al, 2010) and salinity (Jiang et al, 2017).…”