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采用速生树种修复重金属污染土壤的方法近年来受到越来越多关注,但已有结果存在很大不确定性。为了解杨树在不同Pb胁迫条件下生长响应和Pb富集效果,以长江上游两种典型土壤(酸性紫色土和钙质紫色土)为栽培介质,采用盆栽试验方法,研究了不同Pb浓度处理下(CK:0mg·kg-1;T1:200mg·kg-1;T2:450mg·kg-1;T3:2000mg·kg-1)欧美杂交杨(Populus deltoides×Populusnigra)生物量生产与分配格局以及Pb吸收、富集特性。两种土壤条件下杨树各器官生物量及总生物量均表现出随Pb胁迫程度的增加而降低的趋势,Pb胁迫条件下杨树生物量分配格局在钙质紫色土中表现为茎>粗根>叶>细根。相同浓度Pb处理条件下,单株杨树总生物量均表现为钙质紫色土大于酸性紫色土。随着Pb处理浓度的增大,杨树各器官Pb含量及积累量显著增加。Pb胁迫使杨树对Pb的富集系数逐渐增大而耐性系数逐渐减小。T3处理条件下杨树对Pb的富集系数在酸性紫色土中较大,且各处理条件下杨树对Pb的耐性系数均为酸性紫色土中较大。这些结果表明,高浓度Pb胁迫条件下酸性紫色土中的欧美杂交杨表现出较好的吸收和富集Pb的特性,这为Pb污染土壤的生物修复提供了一定的科学依据。
The method of repairing the heavy metal contaminated soil with fast-growing tree species has drawn more and more attention in recent years, but there are many uncertainties in the results. In order to understand the growth response and Pb enrichment effect of poplar under different Pb stress, two typical soils (acid purple soil and calcareous purple soil) in the upper reaches of the Yangtze River were used as the culture media. Pot experiments were conducted to study the effects of different Pb concentrations Populus deltoides × Populus nigra (Populus deltoides × Populus nigra) biomass production and distribution patterns and Pb absorption, enrichment characteristics. Under both soil conditions, the biomass and total biomass of all organs of poplar tended to decrease with the increasing of Pb stress. Under the Pb stress, the biomass allocation pattern of poplar appeared in stem> coarse Root> leaf> fine root. Under the same Pb concentration, the total biomass of single poplar was higher than that of acid purple soil in calcareous purple soil. With the increase of Pb concentration, the content and accumulation of Pb in various organs of poplars increased significantly. Under Pb stress, the enrichment coefficient of poplar to Pb gradually increased and the tolerance coefficient decreased gradually. Under T3 treatment, the enrichment coefficient of Pb in poplar was larger in acidic purple soil, and the tolerance coefficient of poplar to Pb in each treatment was higher in acidic purple soil. These results show that the hybrid Populus euphratica in acidic purple soil shows good absorption and Pb enrichment under high Pb stress, which provides a scientific basis for the bioremediation of Pb contaminated soil.