Selenium uptake and species distribution in peas after foliar treatment with selenate

Abstract

Selenium fertilization of plants has been used to increase the nutritional selenium levels in humans and animals. The speciation of selenium in samples is necessary to understand selenium mobility, uptake and toxicity. The aim of this work was to check the ability of peas to accumulate Se by hydride generation atomic fluorescence spectrometry (HG-AFS) and to identify the selenium species in peas seeds by high performance liquid chromatography-UV photochemical digestion-hydride generation atomic fluorescence spectrometry (HPLC-UV-HG-AFS) using selenomethionine, selenocystine, selenate, selenite and Se-methylselenocysteine standards. In this study pea (Pisum sativum L.) was treated once or twice by spraying leaves with a water solution containing 15 mg Se/L in the form of sodium selenate at flowering time. The average total Se content in seeds was 21 ± 2, 383 ± 19 and 743 ± 37 ng g-1 in nontreated and once and twice foliarly treated plants, respectively. After water extraction 32 ± 3 % of Se was in soluble form and no selenium species were found in extracts under found optimal conditions of HPLC-UVHG- AFS. After enzymatic hydrolysis 92 % of Se was soluble in seeds and a great part of added Se (VI) was converted to selenomethionine representing 49 and 67 % in once and twice treated plants, according to the total Se content. The other part of soluble selenium in supernatants after enzymatic hydrolysis was not detected.