绿洲土Pb-Zn复合胁迫下重金属形态特征和生物有效性

通过对Pb-Zn复合胁迫下干旱区绿洲土壤中油菜种植进行盆栽试验模拟,探讨了重金属复合污染对油菜生长的影响及其各形态之间的转化规律和生物有效性.结果表明,低浓度Pb、Zn处理下,油菜生长得到促进,茎叶生长优势大于根系.随着外源重金属的投加,土壤中Pb、Zn主要赋存形态较对照均由紧结合态向松结合态转化,重金属生物有效性提升;可交换态Pb、碳酸盐结合态Zn分别是油菜不同部位吸收Pb、Zn的主要贡献形态.油菜在低浓度胁迫水平对Pb、Zn的富集能力和转移能力强于高浓度胁迫水平,且油菜对Pb、Zn的富集、迁移系数均随土壤中对应元素或共存元素生物有效态含量的增大而减小.所有处理中,油菜茎叶中的Pb含量均超出了食品安全限量指标,建议在此类土壤种植叶菜类蔬菜前进行相关指标检测.     

阿维菌素在油菜和土壤中残留及降解行为研究

在北京和山东两地对阿维菌素在油菜和土壤中的残留以及降解动态进行了研究.样品衍生化后用高效液相色谱-荧光检测器对阿维菌素进行分析,在0.005 mg·kg-1-0.100 mg·kg-1的浓度下,该方法在油菜和土壤中的回收率分别为88.3%-99.3%和85.9%-95.9%,相对标准偏差分别为4.0%-7.2%和4.4...     

Bioaccumulation and translocation of cadmium in cole （Brassica campestris L.） and celery （Apium graveolens） grown in the polluted oasis soil, Northwest of China

A pot experiment was conducted to study the bioaccumulation and translocation of cadmium (Cd) in cole (Brassica campestris L.) and celery (Apium graveolens) grown in the Cd-polluted oasis soil, Northwest of China. The results showed that Cd in the unpolluted oasis soil was mainly bound to carbonate fraction (F2) and Fe-Mn oxide fraction (F3). However, marked change of Cd fractions was observed with increasing soil Cd concentrations, in which the concentration of Cd in F1 (exchangeable fraction), F2 and F3 increased significantly (p < 0.001 for F1, F2 and F3). The growth of cole and celery could be facilitated by low concentrations of Cd, but inhibited by high concentrations. The correlation analysis between the fraction distribution coefficient of Cd in the soil and Cd concentration accumulated in the two vegetables showed that Cd in F1 in the soil made the greatest contribution on the accumulation of Cd in the two vegetables. The high bio-concentration factor and the translocation factor of Cd in both cole and celery were observed, and Cd had higher accumulation in the edible parts of the two vegetables. Therefore, both cole and celery grown in Cd-polluted oasis soil have higher risk to human health. And the two vegetables are not suitable to be cultivated as vegetables consumed by human in the Cd-polluted oasis soil.     

晋南两熟半干旱区“粮药”(半夏)农田生态抗旱耕作模式效益研究

采用大田试验,设计冬小麦(Triticum aestivum Linn.)在春季起身后套作半夏[Pinellia ternata(Thunb.)Breit.](小麦/半夏)、冬油菜(Brassica campestris L.)收获后复播半夏[Pinellia ternata(Thunb.)Breit.](油菜-半夏)和春玉米(Zea mays L.)与半夏[Pinellia ternata(Thunb.)Breit.]间作(玉米+半夏)3种耕作模式,探讨晋南两熟半干旱区适宜半夏的粮药耕作模式。结果表明:与油菜-半夏、玉米+半夏耕作模式相比,小麦/半夏耕作模式经济产量最高,生态效益最好;不同半夏品种中,西河半夏(原产地温度相对最低)产量最高,新绛半夏(原产地温度相对较高)产量最低。表明半夏适宜于从低温地区引种到高温地区栽培,可提高产量。与商洛半夏和新绛半夏相比,西河半夏分别增产19.1%和41.9%;小麦/半夏耕作模式为最佳粮药耕作模式,其半夏产量与油菜-半夏和玉米+半夏耕作模式相比,分别增产53.4%和70.8%。     

Chemical fractionations and bioavailability of cadmium and zinc to cole （Brassica campestris L.） grown in the multi-metals contaminated oasis soil, northwest of China

A pot experiment was conducted to study the relationship between distribution of cadmium (Cd) and zinc (Zn) and their availability to cole (Brassica campestris L.) grown in the multi-metal contaminated oasis soil in northwest of China. The results showed that Cd and Zn in the unpolluted oasis soil was mainly found in the residual fractionation, however, with increasing contents of Cd and Zn in the oasis soil, the distribution of Cd and Zn changed significantly. The growth of cole could be promoted by low Cd and Zn concentration, but significantly restrained by high concentrations. There was antagonistic e ect among Cd and Zn in the multi-metals contaminated oasis soil. Stepwise regression analysis between fractionations distribution coe cients of the two meals in the soil and their contents in cole showed that both Cd and Zn in the exchangeable fractionation in the oasis soil made the most contribution on the uptake of Cd and Zn in cole. The bio-concentration factor (BCF) of Cd was greater than Zn in cole, and BCFs of the two metals in leaves were greater than those in roots. The translocation factors of the two metals in cole were greater than 1, and the two metals mainly accumulated in the edible parts in cole. Therefore, cole is not a suitable vegetable for the oasis soil because of the plants notable contamination by heavy metals.     

The uptake and translocation of selected elements by cole (Brassica) grown using oasis soils in pot experiments

Pot experiments were conducted on cole (Brassica) grown in soils jointly treated with traces of two heavy metals cadmium (Cd) and zinc (Zn). As the concentration of heavy metals in the soil increased, the uptake of these metals by the plants rose. However, the ratio of heavy metal concentration in soil to uptake by plants increased at a slower rate. Bioavailability of heavy metals considered between the roots and soil using non-linear regressions was shown to be statistically significant. Similarly, the bioavailability of these two heavy metals between leaves and roots using a linear regression was also statistically significant. The bioconcentration factors (BCFs) for Cd and Zn were 0.282 and 4.289, respectively. Significant variation of BCF with the heavy metal bioavailability in soil was noted from non-linear models. The transfer factors (TFs) were 4.49 for Cd and 1.39 for Zn. The Zn concentration in leaves under all treatments did not exceed threshold set standards, but Cd levels exceeded these standards when the concentration of Cd in the soil was more than 1.92 mg kg^?1 dry weight (dw). Data indicate that cole (Brassica) is not a suitable crop for oasis soils because of plant contamination with heavy metals, especially Cd.     

晋南两熟半干旱区“粮药”（半夏）农田生态抗旱耕作模式效益研究

采用大田试验,设计冬小麦（Triticum aestivum Linn.）在春季起身后套作半夏[Pinellia ternata（Thunb.）Breit.]（小麦/半夏）、冬油菜（Brassica campestris L.）收获后复播半夏[Pinellia ternata（Thunb.）Breit.]（油菜-半夏）和春玉米（Zea mays L.）与半夏[Pinellia ternata（Thunb.）Breit.]间作（玉米＋半夏）3种耕作模式,探讨晋南两熟半干旱区适宜半夏的＂粮药＂耕作模式。结果表明：与油菜-半夏、玉米＋半夏耕作模式相比,小麦/半夏耕作模式经济产量最高,生态效益最好;不同半夏品种中,西河半夏（原产地温度相对最低）产量最高,新绛半夏（原产地温度相对较高）产量最低。表明半夏适宜于从低温地区引种到高温地区栽培,可提高产量。与商洛半夏和新绛半夏相比,西河半夏分别增产19.1%和41.9%;小麦/半夏耕作模式为最佳＂粮药＂耕作模式,其半夏产量与油菜-半夏和玉米＋半夏耕作模式相比,分别增产53.4%和70.8%。