Key Laboratory of Western China's Environmental Systems of the Ministry of Education (MOE) & College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
J Sci Food Agric. 2011 Jan 30;91(2):377-84. doi: 10.1002/jsfa.4196.
Crops grown in soils contaminated by heavy metals are an important avenue for toxic metals entering the human food chain. The objectives of our study were to investigate the accumulation and distribution of cadmium (Cd) and lead (Pb) in wheat plants cultivated in arid soils spiked with different doses of heavy metal, as well as bioavailability of these metals in the contaminated arid soils from the oasis, north-west China.
The concentrations of Cd in the roots of wheat plants were about 5, 14 and 8 times higher than those in the shoots, shells and grains, respectively. The concentrations of Pb in the roots were about 23, 76 and 683 times higher than those in the shoots, shells and grains, respectively. Grains contained 11-14% and 0.1-0.2% of Cd and Pb found in roots of wheat plants. The bioconcentration factor (BCF) is the ratio of metal concentration in plant tissues and metal concentration in their rooted soils. The average BCF of Cd and Pb in grains was 0.6270 and 0.0007. Cd and Pb contents in different parts of wheat plants mainly correlated with the bound-to-carbonate metal fractions in contaminated arid soils.
The preliminary study indicated that Cd and Pb were predominantly accumulated and distributed in wheat roots and shoots, and only a small proportion of these metals can reach the grains. The carbonate fractions mainly contributed to Cd and Pb bioavailability in contaminated arid soils.
生长在重金属污染土壤中的农作物是有毒金属进入人类食物链的一个重要途径。本研究的目的是调查在不同重金属剂量污染的干旱土壤中种植的小麦植株对镉（Cd）和铅（Pb）的积累和分布，以及这些金属在中国西北绿洲干旱污染土壤中的生物可利用性。
小麦植株根部的 Cd 浓度分别比茎叶、麦壳和麦粒高出约 5、14 和 8 倍。根部的 Pb 浓度分别比茎叶、麦壳和麦粒高出约 23、76 和 683 倍。麦粒中含有 11-14%和 0.1-0.2%的 Cd 和 Pb，来自于根部的小麦植株。生物浓缩因子（BCF）是植物组织中金属浓度与根系土壤中金属浓度的比值。Cd 和 Pb 在麦粒中的平均 BCF 分别为 0.6270 和 0.0007。小麦植株不同部位的 Cd 和 Pb 含量主要与污染干旱土壤中与碳酸盐结合的金属分数有关。
初步研究表明，Cd 和 Pb 主要在小麦的根和茎叶中积累和分布，只有一小部分金属可以到达麦粒。碳酸盐分数主要影响污染干旱土壤中 Cd 和 Pb 的生物可利用性。
