Uptake of Selenium and its Antioxidant Activity in Ryegrass When Applied as Selenate and Selenite Forms |
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Authors: | P Cartes L Gianfreda ML Mora |
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Institution: | (1) Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Casilla, 54-D Temuco, Chile;(2) Dipartimento di Scienze del Suolo, della Pianta e dell’Ambiente, Università di Napoli, Federico II, Italy;(3) Departamento de Ciencias Químicas, Universidad de La Frontera, Casilla, 54-D Temuco, Chile |
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Abstract: | Selenium (Se) is an essential micronutrient for animal and human nutrition, but whether it is essential to plants remains
controversial. However, there are increasing experimental evidences that indicate a protective role of Se against the oxidative
stress in higher plants through Se-dependent glutathione peroxidase (GSH-Px) activity. The effects of the Se chemical forms,
selenite and selenate, the rate of their application on shoot Se concentration and their influence on the antioxidative system
of ryegrass (Lolium perenne cv. Aries), through the measurement of GSH-Px activity and lipid peroxidation, were evaluated in an Andisol of Southern Chile.
Moreover, a soil–plant relationship for Se was determined and a simple method to extract available Se from acid soils is proposed.
In a 55-day experiment ryegrass seeds were sown in pots and soil was treated with sodium selenite or sodium selenate (0–10
mg Se kg−1). The results showed that the Se concentration in shoots increased with the application of both selenite and selenate. However,
the highest shoot Se concentrations were obtained in selenate-treated plants. For both sources of Se, there was a significant
positive correlation between the shoot Se concentration and the GSH-Px activity; and the Se-dependence of this enzymatic activity
was related especially with the chemical form of applied Se rather than the Se concentration in plant tissues. Furthermore,
the lipid peroxidation, as measured by Thiobarbituric Acid Reactive Substances (TBARS), decreased at low levels of shoot Se
concentration, reaching the lowest level at approximately 20 mg Se kg−1 in plants and then increased steadily above this level. In addition, the acid extraction method used to evaluate available
Se in soil showed a positive good correlation between soil Se and shoot Se concentrations irrespective of chemical form of
Se applied. |
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Keywords: | GSH-Px ryegrass selenate selenite soil available Se TBARS |
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