Laboratory for Soil and Water Management, K.U.Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
Environ Pollut. 2012 May;164:242-7. doi: 10.1016/j.envpol.2012.01.027. Epub 2012 Feb 28.
This study was set up to relate lead (Pb) bioavailability with its toxicity to plants in soils. Tomato and barley seedlings were grown in six different PbCl(2) spiked soils (pH: 4.7-7.4; eCEC: 4.2-41.7 cmol(c)/kg). Soils were leached and pH corrected after spiking to exclude confounding factors. Plant growth was halved at 1600-6500 mg Pb/kg soil for tomato and at 1900-8300 mg Pb/kg soil for barley. These soil Pb threshold were unrelated to soil pH, organic carbon, texture or eCEC and neither soil solution Pb nor Pb(2+) ion activity adequately explained Pb toxicity among soils. Shoot phosphorus (P) concentrations significantly decreased with increasing soil Pb concentrations. Tomato grown in hydroponics at either varying P supply or at increasing Pb (equal initial P) illustrated that shoot P explained growth response in both scenarios. The results suggest that Pb toxicity is partially related to Pb induced P deficiency, likely due to lead phosphate precipitation.
本研究旨在探讨土壤中铅（Pb）的生物有效性与其对植物毒性之间的关系。番茄和大麦幼苗在 6 种不同的 PbCl2污染土壤（pH：4.7-7.4；eCEC：4.2-41.7 cmol(c)/kg）中生长。在污染后，土壤被淋洗并校正 pH 值，以排除干扰因素。番茄在土壤 Pb 浓度为 1600-6500 mg/kg 时，生长减半，大麦在土壤 Pb 浓度为 1900-8300 mg/kg 时，生长减半。这些土壤 Pb 阈值与土壤 pH 值、有机碳、质地或 eCEC 无关，土壤溶液 Pb 或 Pb2+离子活度也不能充分解释土壤间的 Pb 毒性。随着土壤 Pb 浓度的增加，植株磷（P）浓度显著降低。在水培条件下，无论是在不同的磷供应条件下还是在不断增加的 Pb（初始磷相同）条件下生长的番茄，均表明植株 P 含量可以解释两种情况下的生长反应。结果表明，Pb 毒性部分与 Pb 诱导的 P 缺乏有关，可能是由于磷酸铅沉淀所致。
