不同玉米品种对镉的富集和转运特性

通过室外盆栽试验,研究了18个玉米品种在土壤外加全镉含量为5.0 mg·kg~(-1)条件下对镉的富集和转运差异,并探讨土壤镉形态与玉米吸收镉之间的关系。结果表明:供试玉米品种的生物量和产量以及根、茎、叶、籽粒积累和转运镉的能力存在显著差异,其中9个玉米品种籽粒镉含量未超过国家食品安全卫生标准(GB 2762—2012),3个玉米品种的茎镉含量和2个玉米品种的叶镉含量均未超过国家饲料卫生标准(GB 13078—2001);根、茎、叶、籽粒部位镉的富集系数范围分别为1.076~1.991、0.093~0.430、0.068~0.902和0.004~0.081。茎叶和籽粒镉的转运系数范围分别为0.19~0.83和0.03~0.44,表明土壤镉从玉米地下部向地上部迁移的能力较弱。玉米吸收镉与土壤中可交换态镉有一定的正相关关系,与残渣态镉有一定的负相关关系。经综合评价,新东单16、东单60、沈禾118和富友9可作为镉中轻度污染土壤上种植玉米的优先选择品种。

Accumulation and translocation of cadmium in different maize cultivars

Eighteen maize cultivars, which are widely planted in the Northeast China, were selected as materials in a pot experiment. The aims of this study were to investigate the rule of cadmium (Cd) accumulation and translocation under Cd stress conditions (5 mg·kg^-1), and explore the relationship between Cd form and its absorption by the crop. The results showed that the biomass and yield among cultivars were not significantly different, while the ability to accumulate and translocate Cd was significantly different in the root, stem, leaf, and grain of maize. Among the cultivars, accumulation of Cd in the grain in nine cultivars did not exceed the national hygienic standard of food safety, while that in stem in three cultivars and in leaves in two cultivars did not exceed the hygienic standard of feed. The Cd accumulation coefficients in root, stem, leaf, and grain of maize were 1.076~1.991, 0.093~0.430, 0.068~0.902, and 0.004~0.081, respectively. The transferring coefficients of stem and leaf ranged from 0.19 to 0.83 and from 0.03 to 0.44, respectively, which suggest that the maize cultivars had a certain ability to absorb Cd from the soil, but the transporting ability from shoot to stem, leaf, or grain was weak. Cd absorbed by maize had a positive correlation with the exchangeable state and negative correlation with the residual state. According to the evaluation of biomass, Cd content, enrichment, and transferring coefficient, four cultivars named Xin Dongdan 16, Dongdan 60, Shenhe 118, and Fuyou 9 could be recommended for cultivation in the mild and moderate Cd contaminated soils.