Assessment of lead tolerance in 23 Chinese soybean cultivars and the effect of lead on their mineral ion complement.

The selection and breeding of lead pollution-safe cultivars (Pb-PSCs) has been used to minimize the influx of Pb into the human food chain. We examined the growth response of 23 selected soybean cultivars to various lead concentrations and also assessed their tolerance to lead. Variations in uptake, enrichment, and translocation of lead among these cultivars were studied to screen out soybean Pb-PSCs. The results indicated that the seed Pb concentrations under three Pb treatments (500, 1,000, and 2,000 mg kg(-1)) varied significantly (P < 0.05), with average values of 0.20, 0.25, and 0.33 mg kg(-1), respectively. Cultivars Shennong 6, Shennong 8, Tiefeng 29, Tiefeng 37, Ji 1005, Liaodou 15, and Suke 1 were found to fit the criteria for Pb-PSCs. The seeds of these seven cultivars were further assessed for interactions between Pb and other mineral nutrient elements such as Ca, Cu, Fe, Mg, Mn, and Zn. High lead concentration in soil was found to inhibit the uptake of Ca, Cu, Fe, Mg, and Zn. Furthermore, Mn accumulation was found to be enhanced in the seeds of all of the seven Pb-PSCs in response to high Pb concentration.