Absorption adn Accumulation of Heavy Metals in Amaranth Under Stress of Multiple Salt Ions

Reference to the salt and heavy metals content in the pore water of tidal flat soil which was in different leaching and desalinization stages, a hydroponic experiment of amaranth was carried out to investigate absorption,accumulation and transportation of six heavy metals (Zn, Cu, Ni, Cr, Pb and Cd)by the plant under the combined effect of a variety of salts(SO₄^2-、Cl^-、NO₃^-、CO₃^2-、Na⁺、Ca²⁺、K⁺and Mg²⁺,etc.). Results show that compared with what was observed in the control, under the effects of salt ions different in concentration,the content of Cd in stems and leaves of the plant increased by 69.2% -146.2%, while the contents of other heavy metals did not change much;the content of Cd,Pb,Cr,Ni and Cu in roots of the plant increased by 187.8%, 197.7%, 305.7%, 228.1% and 58.2%, respectively,but that of Zn was not significantly affected. In the culture with salt ion concentration being more than 1312.4 mg·L^-1, the contents of the six heavy metals in roots and shoots did not vary much between treatments different in salt concentrations,separately.Salt treatment apparently reduced the translocation coefficients of Pb, Cr, Ni and Cu in amaranth from the roots to the shoots, but it did not affect much that of Cd and Zn.