Effects on seeds germination and bioaccumulation of lead in white mustard in a laboratory study

Abstract

The paper presents a laboratory study concerning the Pb effects on seeds germination and bioaccumulation in the white mustard plants (Sinapis alba). The garden soil rich in nutritive elements was watered with Pb solutions until the concentration of 45 mg·kg-1 and 85 mg·kg-1. After 60 days of exposure, the contents of Pb in soil and plant organs were evaluated. The Pb transfer (TC) and translocation (TF) indices were calculated. In addition, the effect of Pb pollution on the assimilation of essential metallic elements (Zn, Ca, Mg, Cu, Ni, Fe, Mn) in plants was investigated. Pb (85 mg·kg-1) can cause negative effects on seed germination (40 % inhibition). The Pb was immobilized by the plant at the root level, both in the control and in the exposed samples (TC and TF < 1). The absorption and translocation processes of the essential metals are influenced by the increasing Pb concentrations. Their presence decreases the toxicity of Pb to both tested concentrations. Competitive processes were observed between Pb (45 mg·kg-1) and Ca, Mg, Zn, Cu, and Mn. Antagonistic processes of Pb were observed in the case of Fe, Cu, and Ni in the plant. At 85 mg·kg-1 Pb inhibition or stagnation of accumulation compared to the control was noticed. The photosynthesis process measured through chlorophyll detection revealed no significant influences of Pb. Phytotoxic effects are reduced. The results revealed that Sinapis alba have the capacity to adapt to Pb contamination having a great phytostabilization potential.