Tõnu Tõnutare

Effect of Selenium Treatment on Mineral Nutrition, Bulb Size, and Antioxidant Properties of Garlic (Allium sativum L.)

Foliar selenium (Se) treatment of garlic at concentrations of 10, 50, and 100 μg of Se/mL was carried out in open field conditions in 2008 and 2009 in Estonia. Bulb weight and yield structure, content of total Se, S, N, P, K, Ca, and Mg, ascorbic acid content (AAC), pungency, total phenolics, and total antioxidant capacity (TAC) were determined. The highest level of Se decreased total S, K, and Ca in both years; no negative impact on bulb weight was observed. In 2009 Se10 treatment had significantly more bulbs with the largest diameter compared to the other treatments. In 2008, the AAC was decreased by Se50 and the content of total phenolics by all Se treatments; however, TAC was increased. Foliar Se fertilization of garlic at rates of 10-50 μg of Se/mL can be recommended to increase the number of large bulbs and increase bulb antioxidant capacity.

Composition of commercially produced organic and conventional strawberries

Purpose – The purpose of this study was to determine differences in taste-related and bioactive compounds of organically (OR) and conventionally (CONV) cultivated commercially produced strawberries (Fragaria × ananassa Duch.). Addresses the question if the consumers buying OR strawberries are likely to purchase fruits with better taste and richer in bioactive compounds than those buying CONV fruits. Design/methodology/approach – Only information commonly available to the consumers [cultivar, quality class, product origin (country) and eco-labelling], was considered in selecting experimental material. “Polka” strawberries from 14 farms (7 OR and 7 CONV) from South Estonia were used for analyses. Findings – No evidence was found that OR strawberries contain more bioactive compounds or have higher soluble solids content and titratable acids ratio (associated with better taste) compared to CONV strawberries. There were significant differences in content of total phenolics, anthocyanins, ascorbic acid, vitamin...

Accumulation of metallic elements into the superficial peat layer of mires and wet mineral soils of Estonian forest land / Akumulacja metali w powierzchniowej warstwie gleb torfowych i wilgotnych glebach mineralnych ekosystemów leśnych Estonii

Abstract This article studied the extent of accumulation of aqua regia extractable metallic elements (Al, Mg, Pb, Zn, Hg, Cd) into peaty (histic) epipedon (EP) of fen soils, transitional bog soils, peaty gley soils and peaty podzols. The accumulation coefficients (Kac) of the elements in EP were estimated in relation of forest floor (FF, as an input) as a comparison to deeper levels (SS, as a past background). The study revealed that the extent of accumulation and its order depend on soil (peat) type or pedo-ecological conditions of peatification. In the forming of EP from FF, the concentrations of Al and Pb were increased on an average 2.5-5.0 times, but that of Hg increased significantly only in peaty soils (on an average 1.5-1.6 times). The contents of Zn were significantly decreased (Kac 0.1-0.5) in all soil groups. The comparison of EP peats concentrations with SS data demonstrated a considerable accumulation of Pb, Cd, Zn and Hg into thin (~20 cm) superficial peat layer. Streszczenie Z wykorzystaniem wody królewskiej badano stopień akumulacji metali (Al, Mg, Pb, Zn, Hg, Cd) w epipedonie torfów wysokich (EP), torfów przejściowych, oglejonych glebach torfowych oraz zabagnionych glebach bielicowych. Współczynnik akumulacji metali (Kac) w EP oszacowano w zależności od runa leśnego (FF, jako wkład) i w porównaniu do głębszych poziomów (SS, jako tło przeszłości). Stwierdzono, że stopień akumulacji metali jest uzależniony of typu gleby (torfu) oraz jej właściwości. W powstałym EP z FF stężenia Al i Pb zwiększyły się średnio 2.5-5.0 razy, natomiast Hg istotnie jedynie w glebach torfowych (średnio 1.5-1.6 razy). Istotnie zmniejszyły się (Kac 0.1-0.5 razy) zawartości Zn we wszystkich glebach. Porównując zawartości metali w EP z SS stwierdzono znaczącą akumulację Pb, Cd, Zn i Hg w (~20 cm) powierzchniowej warstwie torfowej.