THE INFLUENCE OF LEAD ON THE CONTENT OF POLYPHENOLS IN SEED OF FLAX UNDER MODEL CONDITIONS

Abstract

In this work the level of risk of enhanced heavy metal contents in selected crop cultivated in model conditions of the pot trial after different Pb doses addition and in real conditions (Považie area) was evaluated. We also investigated the effect of accumulation of heavy metals content (mainly lead content) on total polyphenols content and antioxidant activity. Four variants of the experiments: control (without Pb addition, only fertilisation) and next three variants were realised. Lead in the form of water-soluble salt of Pb(NO3)2 was applied in gradual specific doses with 5 (variant B), 10 (variant C), 15 (variant D) multiple as the limit value by the Law no. 220/2004 Z.z. to assess the state of soil contamination. For the experiment the flax seeds cultivar Electra were used.
The flame AAS (AAS Varian AA Spectr DUO 240 FS/240Z/UltrAA) was used for the determination of heavy metal contents in soil and plant materials. The total polyphenol content (TP) was estimated using Folin-Ciocalteau assay and the total antioxidant capacity of legume extracts was measured using the DPPH spectrophotometrically.
All determined Pb (with exception C variant) and Cd contents were higher than maximal allowed amounts given by the Food Codex of the Slovak Republic.In all variants with Pb addition the TP value was lower than those in the control variant. Higher levels of polyphenolic compounds in flax seeds showed a higher antioxidant capacity values due to increased doses of lead.