不同叶菜品种镉积累评价及降低镉积累的措施

为探明不同叶菜品种在镉污染条件下对镉的吸收、转运与积累特征，选取适宜上海地区种植的13个叶菜品种菠菜（Spinacia oleracea L.）、青菜（Brassica rapa var.chinensis （L.）Kitam.）和生菜（Lactuca sativa var.ramosa Hort.）3个种类]，比较其在镉污染农田中的镉积累差异，并分析影响可食部位镉积累的相关因素，同时探究土壤重金属钝化肥和重金属叶面阻控营养强化肥单独和联合施用对降低上海矮青（Brassica rapa var.chinensis （L.）Kitam.）镉积累的效果。结果表明：不同叶菜品种地上部和根部镉含量存在显著差异，总体分布规律为地上部>根部，变化范围分别为1.58~12.80 mg·kg^-1（以干质量计）和0.24~3.54 mg·kg^-1（以干质量计）；不同叶菜品种根部向可食部位转运镉的能力存在显著差异，其中品种V3（新夏青6号）转运系数最低，转运系数最高品种是最低品种的6倍。相关性分析表明，叶菜可食部位镉含量受根部镉含量影响最大，受土壤总镉影响最小。叶菜具有较强的镉富集能力，供试叶菜品种可食部位的富集系数均大于1。施用土壤重金属钝化肥和重金属叶面阻控营养强化肥能够显著降低上海矮青可食部位镉的积累、吸收和转运。综合考虑叶菜可食部位镉含量、产量、转运系数和富集系数，适合在该地区种植的叶菜品种为V4（金品鸡毛菜3号）、V2（新夏青3号）和V6（夏福），同时，采取合理的农艺/化学措施是降低污染土壤中重金属积累、保障农产品安全生产的有效策略。

Evaluation of cadmium accumulation in different leafy vegetable cultivars and approaches for reducing accumulation

Thirteen leafy vegetable varieties of three species including Spinacia oleracea L., Brassica rapa var. chinensis(L.)Kitam., and Lactuca sativa var. ramose Hort. that were suitable for local cultivation planted in Cd-contaminated fields were selected to study differences in Cd accumulation and the factors influencing Cd accumulation in the edible parts. Additionally, the effects of combined treatments of soil amendments and foliage fertilizer on Cd accumulation in Shanghai Aiqing(Brassica rapa var. chinensis(L.)Kitam.)were investigated. The results showed that among the 13 leafy vegetable cultivars, there were significant differences in the Cd content in the edible parts and roots;the distribution pattern generally was edible part > root. The Cd translocation ability varied clearly among the different leafy vegetable cultivars, and V3(Xinxiaqing-6)exhibited the lowest root to edible part translocation factors. Correlation analysis showed that the Cd content of the edible part was most affected by the Cd concentration in the roots and least affected by the total Cd content of the soil. Leafy vegetables had strong Cd enrichment ability, and the bioaccumulation coefficients of the edible parts of the tested leafy vegetables were greater than 1. Soil amendment or foliage fertilizer treatments showed positive influence on reducing Cd absorption, translocation, and accumulation in Shanghai Aiqin. Considering the Cd concentration in edible parts, yield, translocation factors, and bioaccumulation coefficients, V4(Jinpin Chinese green vegetable-3), V2(Xinxiaqing-3), and V6(Xiafu)are suitable varieties to be planted in this region, and the application of reasonable agronomic/chemical measures is an efficient strategy to reduce heavy metals accumulation in contaminated soil to produce safe products.