The effect of a growth regulator Ribav-Extra on winter wheat seedlings exposed to heavy metals

We studied the influence of a natural plant growth regulator Ribav-Extra and ions of heavy metals (HM) Pb2+, Cu2+, Zn2+ and Ni2+ on the physiological and biochemical indices of the winter wheat (Triticum aestivum L.) cultivar 'Mironovskaya 808'. The seeds of wheat were treated with Ribav-Extra (10 ppm) and grown for 7 days on heavy metal salt solutions (10 mu M or 1 mM). After that we recorded heavy metals accumulation, growth, generation of superoxide anion (center dot O-2(-)), lipid peroxidation (LPO), and catalase (CAT) and ascorbate peroxidase (APOX) activity. It was found that 1 mM of HM in growth media increased heavy metals accumulation in wheat plants and inhibited the growth of roots and shoots. Both low and high concentrations of heavy metals stimulated center dot O-2(-) production and oxidative damage in wheat seedlings. In most treatments, the toxic effect of heavy metals enhanced at higher concentration of metals. Pre-sowing treatment of seeds with Ribav-Extra decreased the negative impact of heavy metals by reducing oxidative stress which led to suppressed center dot O-2(-) generation, lipid peroxidation intensity and catalase activity. This suggests that the wheat plants, whose seeds had been treated with Ribav-Extra, were more heavy metal-resistant than the untreated ones.