Genotoxic Cd and Pb effects and modifying potassium humate influence on wheat growing on soil polluted by heavy metals

The genotoxicity of Pb and Cd for the spring soft wheat variety Voroneshskaya 6 was tested in greenhouse trials. The protective function of presowing seed treatment by potassium humate (PH) was also done. Pb and Cd were introduced in the form of their nitro-acid salts at a dose of Cd-30 and 50, Pb-200 and 750 milli g per soil kg at tumbler filling by sod-podzol loamy soil. The seeds were treated by PH-containing preparation Agrospej (the Russian Federation) at a dose of 0.6 ml per seed kg. The analysis of chromosome aberrations in intercalary meristems of apical point was made at the beginning of the leaf-tube formation plant stage. It showed that Cd led to the rise of abberant cell rate (ACR) in 1.6 and 1.8 times depending on the dose. The presowing seed incrustation by PH decreased ACR till background meanings 11.00 and 13.52% at the control meanings of 12.25 and 13.72%). The ACR dependence on a dose was not marked for the trial variants with Pb soil contamination (17.3 and 18.25). The rate increase of cytogenetic disruptions was 1.4 and 1.5 times, but it had a statistical importance only at a dose of 750 milli g per kg that was probably connected with less Pb absorption by the plants and higher soil buffer capacity for the element in compare with Cd. The treatment by PH decreased disruption level in 1.5 times till 12.01%. The ratio of a total aberration number to total aberrant cell number changed insignificantly depending on the trial variants. The same case was also fixed in relation to a plant height and its dynamics and the most of productivity components. The exception was the variant with treatment by PH at the Cd contamination at a dose of 30 milli g per kg where grain weight of a plant fell down (from 1.22 g to 0.84 g in compare with the control variant). The conclusion was made that the growth regulator PH modified heavy metal genotoxic action decreasing chromosome disruptions without phytotoxic effect reducing.