Selenium is a trace element with multiple functions in animal and human nutrition. Deficiency in selenium reported for sheep bred in Central Dobrogea, required to initiate a comprehensive study on the abundance of total Se in parental rocks, in soil and wheat plants (the whole plant, on 5-6 stage by Feeks scale, and the grain at maturity) from the southeastern Romanian Plain and Central and South Dobrogea. 17 samples of rocks and parental materials, 101 soil samples, 83 samples of wheat during the vegetation period, and 49 samples of wheat at maturity stage, were analyzed in terms of total and mobile selenium content in rocks and soils, and the total selenium in plants. Also, other chemical properties of the collected samples were determined. Analytical results obtained, compared with similar results from literature, have shown that both in rocks and soils, the selenium content in our country is lower than in other areas of the world, unaffected by the phenomenon of deficiency or toxicity in this microelement. Thus, compared to the normal average total selenium content of the worldwide soils (0.383 ± 0.255 mg·kg-1), in the South-Eastern Romanian Plain soils and in Dobrogea soils, the average total selenium content is 38%, respectively, 63% lower. Moreover, in Dobrogea deficiency phenomenon is more intense. Average content of mobile selenium, soluble CH3COONH4-EDTA solution at pH 7, of the Central and Southern Dobrogea soils is 3.5 times lower compared with that of the South-Eastern Romanian Plain soils (0.014 mg·kg - 1). If in wheat plants during the vegetation the selenium content (0,130 mg.kg-1) was close to normal (0,146 mg.kg-1), recorded in wheat plants grown in different countries with soils that are not affected by selenium deficiency or excess, in grains of wheat obtained in the south-east of the country the selenium content was lower, and the grains of wheat, particularly those obtained on Dobrogea soils, selenium content tended to be a value below the detection limit of the method (5 • 10 -4 mg • kg-1) used for analysis. It outlines the need to bio-fortify with selenium the wheat flour obtained from Central and Southern Dobrogea wheat or mixing it with other wheat that was cultivated in other climatic zones.

total selenium content; mobile selenium content; loess; green schist; Chernozem; Kastanozems; wheat

Presentation: oral