模拟铅胁迫下玉米不同基因型生长与铅积累及各器官间分配规律

我国遭受重金属污染的土地中有87%左右是中轻度污染土壤类型,深入研究不同植物对重金属的吸收和转运积累规律,是科学利用植物和土壤资源的重要基础工作。通过玻璃网室盆栽模拟污染的手段,研究了玉米6种基因型在铅中度污染胁迫（800mg·kg^-1）与轻度污染胁迫（400mg·kg^-1）下的植株生长、铅吸收积累及其在玉米不同器官间分配的规律。结果表明,不同铅污染胁迫下,玉米不同基因型的生长及铅吸收量达到极显著差异（P〈0.01）,铅在不同器官之间的分布形式也存在显著的基因型差异。轻度铅污染胁迫不同程度地促进玉米所有供试基因型的生长,而中度污染胁迫下糯玉米基因型生物量最大。与正常土壤对照条件下的表现相比,不同程度铅污染胁迫下基因型申甜1号的生物量增幅最大,表现出较强的铅耐受能力。不同基因型的玉米体内铅积累量随着污染水平的提高而增加,各器官内铅积累浓度差异规律为根〉叶〉茎〉穗。掖单13号具有较强的铅转运能力（TF=0.6628）,申甜1号的生物富集能力最强（BCF=0.0264）,掖单13号和申甜1号均具有较强的铅吸收和积累能力,属于潜在的高积累基因型。但掖单13号根部富集量少而穗部积累多,申甜1号根中铅积累较多而果穗中较少。2个甜玉米基因型果穗内铅积累量较少,其含量符合国家规定的食品生产相应的安全标准。

Plant Growth,Lead Uptake and Partitioning of Maize（Zea mays L.） Under Simulated Mild/ Moderate Lead Pollution Stress

Mild/moderately polluted soil accounts for about 87 percent of all heavy metal contaminated soil area in China. To a better utilization of these mild/moderately polluted soil,the most important approach might include phytoremediation which was based on deep understanding of the uptake,translocation and partitioning of heavy metal in various plants and genotypes. The experiment was conducted to compare the crop growth,lead uptake and partitioning of six genotypes of maize（Zea mays L.） under artificial simulating moderate（800 mg·kg^-1 Pb）,mild（400 mg·kg^-1 Pb） and no-pollutant-addition conditions in greenhouse. The results showed that significant difference（P0.01） in plant growth,lead absorption and partitioning of absorbed lead were found among six different genotypes of maize under both moderate and mild lead pollution stress.Under mild lead pollution（Pb400）,the growth of all maize genotypes tested were significantly promoted.The waxy genotypes among the six genotyped showed the biggest biomass at moderate pollution level（Pb800）. Compared to the no-addition control,Shentian-1 showed a significant increase in biomass,implying its strong tolerance to lead contamination stress.The lead accumulated in maize increased along with lead pollution stress.Lead accumulated in various organs of maize showed as：rootleaf culmear. The Genotypes Yedan-13 and Shentian-1 performed higher lead uptake capacity with different partitioning characteristics that Yedan No.-13 accumulated more lead in its edible part while Shentian-1 accumulated most of absorbed lead in its belowground part than that in ear.Yedan-13 had a lead transportation factor（TF） of 0.662 8,while Shentian-1 had a lead bioconcentration factor（BCF） of 0.026 4. These indicated that both genotypes have higher uptake and accumulating ability,implying that those two genotypes of maize could be potentially used as high accumulating plants for lead-contaminated soil restoration.The lead concentration in edible part of two sweet baby corn genotypes（cv. Jinzhumichaotian and cv. Shentian No.1） was within the limitation of state＇s food safety requirements.