Toxicity and bioaccumulation of heavy metals in spinach seedlings grown on freshly contaminated soil

This study was conducted to investigate the toxicities of 3 different doses of cadmium (cd),lead (pb),and zinc (zn) in both single and mix forms on the growth parameters (shoot and root fresh and dry weights,root and shoot lengths,shoot diameter,number of leaves,cell size and mitotic index) of spinach seedlings. soil from historically uncontaminated site was taken and after air drying and sieving (2 mm mesh sieve) was spiked with selected metals. plastic pots filled with spiked soil and seedlings of spinach were prepared in greenhouse environment. growth parameters were calculated according to standards methods and heavy metals (hms) were extracted from plant tissues in digestion block with the help of acid mixture (15 ml) of hno3,hclo4,and h2so4 (5:1:10),and concentrations of hms were measured using atomic absorption spectrometer (analyst 700 of perkelmer). increasing concentrations of cd,pb and zn in both single and mixture forms significantly (p<0.05) reduced growth parameters of s. oleracea seedlings. the reduction in growth parameters of s. oleracea seedling showed the dose response for cd,pb and zn in both single and mixture forms. the uptake patterns of cd,pb and zn in cd/pb,cd/zn and pb/zn showed antagonistic impacts on each other and uptake pattern was reflected in growth of the seedlings. toxicities caused by selected hms were highest for cd followed by pb and zn. highest toxicity was observed in plant seedlings grown on cd/pb treated soil.