Effect of Some Heavy Metals on Seed Germination and Seedling Growth in Fodder Turnip (Brassica rapa L. var. rapa)

In this study, effect of some heavy metals (Pb, Cu, Cd ve Mn) in the form of nitrate salt at different concentrations (0.5, 1, 3, 5 ve 7.0 mM) on seed germination and root-shoot growth in Brassica rapa L. var. rapa (fodder turnip) were investigated. After surface sterilization, the seeds were allowed to inflate in 5 ml solutions at the determined concentrations of heavy metals, while the control group was inflated in distilled water for 6 hours. At the end of this period, the seeds taken from the swelling medium were sown on the double layer rough filter papers, which were soaked in 5 ml of swelling medium liquid in 9 cm plastic petri-dishes, with 25 seeds on each dishes. Immediately after sowing, the petri-dishes were covered and kept into plant growth cabinet to germinate in the dark at 23 ± 1 oC for 72h. The germination rates of seeds were determined at the end of 72 hours on the basis of radicula formation. At the end of the period, root and shoot lengths of the germinated seeds in each group were also measured and recorded. It has been determined that seed germination and root-shoot growth decrease in parallel with the increase in applied heavy metal concentrations. Detection of the highest germination percentage of fodder turnip (known as Pb-tolerant) in Pb treatment after Mn proves that the toxicity threshold value of this species is high.