1.1 Plant material and conditions of cultivation

In the three-year period 2005-2007 spring wheat (Triticum aestivum L.) "Vanek" variety (maintenance of variety: Lochow-Petkus, GmbH, Germany, producer: Selekta, Inc., Czech Republic) was cultivated at 10 m2 trial field plots outside environment (50°2’0"N, 14°36’54"E) on brown loamy soil. Every tested compound was applied in four replicates (10 m2 field plots). There were sowed 217 kg of seeds per hectare. As foregoing crop broad bean was cultivated on the trial field before wheat plants every year and before wheat sowing the field was fertilized with the dose 60 kg N ha-1 with nitrogen-phosphorus-potassium fertilizer. Average content of minerals in trial field soil is described in Table 1.

In another experiment spring wheat, Vanek variety (maintenance of variety: Lochow — Petkus, GmbH, Germany, producer: Selekta, Inc., Czech Rep.) was cultivated for two years (2006, 2007) in pots in the outside environment. Plants were cultivated in the soil anthropogenic contaminated with heavy metals from the location Pribram, Central Bohemia, historically polluted from metal ores mining and smelting activities. Average content of minerals in contaminated soil are given in Table 2. Sowing was performed into the pots of 5 L volume filled with 5 kg of homogenized soil. Each pot was fertilized with the same dose of NPK (1.43 g N in the NHNCb form, 0.16 g P and 0.40 g K in the K2HPO4 form). The final number of plants in a pot was twenty. Plants were irrigated with demineralised water.

Weather conditions in cultivation period (from April to July) were similar in both years. Mean air temperature in both years was higher compared with the long-term normal. Mean precipitation in 2006 was higher in April, May and June, lower in July compared with the long-term normal. In April and May 2007 mean precipitation was by 25 per cent lower than normal and in June and July was higher compared with the long-term normal.