The changes of the antioxidant (AOA) and antiradical activities (ARA) and the total contents of phenolics, anthocyanins, flavonols, and hydroxybenzoic acid in roots and different aerial sections of Echinacea purpurea, nettle, and dandelion, after treatment with ornithine decarboxylase inhibitor, a polyamine inhibitor (O-phosphoethanolamine, KF), and a phenol biosynthesis stimulator (carboxymethyl chitin glucan, CCHG) were analyzed spectrophotometrically; hydroxycinnamic acids content was analyzed by RP-HPLC with UV detection. Both regulators increased the AOA measured as inhibition of peroxidation (IP) in all herb sections, with the exception of Echinacea stems after treatment with KF. In root tissues IP was dramatically elevated mainly after CCHG application: 8.5-fold in Echinacea, 4.14-fold in nettle, and 2.08-fold in dandelion. ARA decrease of Echinacea leaves treated with regulators was in direct relation only with cichoric acid and caftaric acid contents. Both regulators uphold the formation of cinnamic acid conjugates, the most expressive being that of cichoric acid after treatment with CCHG in Echinacea roots from 2.71 to 20.92 mg g(-1). There was a strong relationship between increase of the total phenolics in all sections of Echinacea, as well as in the studied sections of dandelion, and the anthocyanin content.

Selenium (Se) is one of the elements that determine the normal functioning of an organism; it has antioxidant properties and protects the organism against the actions of free radicals and carcinogenic factors. Selenium is an element that fulfils an important physiological function (Kieliszek and Blažejak 2013), but apart from all the elements, selenium has one of the narrowest range between dietary deficiency (< 40 µg/day) and toxic levels (> 400 µg/day) (Fordyce 2007).While there is no evidence of Se need for higher plants, several reports show that when Se added at low concentrations, it exerts beneficial effects on plant growth. Se may act as quasi-essential micronutrient through altering different physiological and biochemical traits; thus, plants vary considerably in their physiological and biochemical response to Se (El-Ramady et al. 2016).During the last decade, studies related with strategies for Se biofortification in food plants for human nutrition have increased significantly because this metalloid is incorporated into human metabolism mainly as a constituent of food plants (Mora et al. 2015). Biofortification is defined as the process of increasing the bioavailable concentrations of essential elements in the edible portions of cultivated plants through agricultural management (fertilization) or genetic improvement (White and Brodlay 2005).Plant-derived foodstuffs, namely cereals, are the major dietary sources of Se in most countries throughout the world, even if Se contents are strongly dependent upon the corresponding levels in cereal-growing soils. Therefore, wheat is one of the staple crops that appears as an obvious candidate for Se biofortification, considering its Possibility of selenium biofortification of winter wheat grain

The influence of application of increasing doses of selenium (0.05 mg, 0.10 mg and 0.20 mg/kg) into soil in pot experiments, with NPK fertilization of spring wheat (Triticum aestivum L., variety Banti), on the biomass yield (grain, straw, roots) and on selenium accumulation was observed. Selenium in the form of sodium selenite (Na 2 SeO 3 ·5H 2 O) and the NPK nutrients in the form of LAD-27, Ca(H 2 PO 4 ) 2 and KCl were applied. The average two-year results showed the expected indifferent effect of increasing doses of selenium on the yield of wheat grain, straw and roots. The differentiated doses of selenium into soil caused a significant increase of selenium content in dry matter (dm) of grain, straw and roots of wheat. The highest content of selenium (0.732 mg/kg in grain, 0.227 mg/kg in straw and 1.375 mg/kg in roots dm) was determined in the variant where 0.2 mg Se/kg of soil was applied. When applying the lowest dose of selenium (0.05 mg Se/kg of soil) the content of selenium was 0.155 mg Se/kg in grain. The selenium content in individual analysed parts of wheat was increasing in the following order: straw -grain -roots.

The effect of foliar application of graduated Se rates (0.5, 1.0, 10 and 20 g Se/ha) on the winter wheat grain yield and Se accumulation in grain was investigated in the accurate field fertilization experiment. Selenium fertilization was realized together with the application of liquid fertilizer DAM-390 (30 kg N/ha) in the growth stage of the 6 th leaf (Zadoks = 29). Applied treatments of Se fertilization did not influence the yields of grain. These yields fluctuated within the range of from 5.98 to 6.08, 5.65 to 5.71, and 7.78 to 8.04 t/ha of grain in the years 1999, 2000 and 2001, respectively. Highly significant lower grain yields in the year 2000 comparing to the other experimental years were caused by unfavorable weather conditions. Both the rates of 10 and 20 g Se/ha highly significantly increased Se accumulation in grain in all experimental years. The average Se content in grain dry matter was 0.045 mg/kg under unfertilized treatment and with the Se rates of 10 g and 20 g/ha it increased to the value of 0.088 and 0.145 mg/kg, respectively. The total offtake of Se by grain yield increased in the similar way. It results from the experiment that the rate of 10 g Se/ha is sufficient for achieving the required Se content in winter wheat grain.

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