(tetraploid ‘Lutea’, Asteraceae) germinated in sand (with 3–4 first true leaves) were placed into Hoagland solution containing 14.622 mM N composed from inorganic nitrate N – 14.1 mM and inorganic ammonium N – 0.522 mM (Kovácˇik & Klejdus, 2008; Kovácˇik et al., 2011b).