不同基因型甘薯(Ipomoea batatas Lam.)吸收累积Cd的特征差异性研究

Absorption and Accumulation of Cd in Different Sweet Potato(Ipomoea batatas Lam.)Genotypes

采用旱地小区试验,研究了Cd污染土壤中甘薯吸收累积Cd的品种差异,探讨了甘薯吸收累积Cd的相关机理。结果表明,甘薯品种间不仅生物量差异较大,对Cd的吸收累积能力也不同,8个品种的地上部茎叶生物量（DW）在4 594.9-8 232.2 kg.hm^-2,鲜样Cd含量范围为0.032 9-0.057 4 mg.kg^-1;地下部块根生物量（DW）在7 809.0-14 269.7 kg.hm^-2,鲜样Cd含量范围为0.002 2-0.011 0 mg.kg^-1,茎叶Cd含量明显高于块根,但均未超过国家食品中污染物限值标准（GB 2762—2005）（根茎类蔬菜〈0.1 mg.kg^-1）。而与无公害蔬菜质量标准（GB 18406.1—2001）进行比较（〈0.05 mg.kg-1）,有3个甘薯品种（心香、湘薯15、泉薯9号）的茎叶Cd含量超标。因此,轻度Cd污染土壤种植的甘薯其茎叶可能存在摄食健康风险,而块根基本无风险,若将Cd污染土壤改制种植甘薯,必须妥善处理其地上部茎叶。

Field experiment was adopted to study the differences of Cd absorption and accumulation among different species of sweet potato（Ipomoea batatas Lam.）and its relevant mechanism in Cd polluted soil.The results showed that the differences existed not only in biomass,but also in Cd absorption and accumulation among sweet potato species.Among the eight sweet potato species,their stem and leaf biomass（DW）varied from 4 594.9 kg.hm-2 to 8 232.2 kg.hm-2,and their Cd conten（tFW）varied from 0.032 9 mg.kg-1 to 0.057 4 mg.kg-1;while root biomass（DW）was between 7 809.0 kg.hm-2 and 14 269.7 kg.hm-2,and the range of their Cd conten（tFW）was from 0.002 2 mg.kg-1 to 0.011 0 mg.kg-1.The Cd content in stem and leaf was significantly higher than that in root,but did not exceed the maximum levels of contam-inants in the national food safety standard（GB 2762—2005）（〈0.1 mg.kg-1）.Compared with the safety for pollution-free vegetable（GB 18406.1—2001）（〈0.05 mg.kg-1）,Cd contents in stem and leaf of three sweet potato species（Xin xiang,Xiang shu No.15,Quan shu No.9） were over standard.Therefore,There is non-feeding health risk of edible roots of sweet potato grown in the mild Cd polluted soil basically,while there may be health risk of stem and leaf of sweet potato by food-chain for feeding.If changing cropping system to plant sweet potato in Cd polluted paddy soil,the stem and leaf of sweet potato should be dealt with properly.