利用富镉基质栽培快速比较不同叶菜镉累积能力的差异

Comparison in cadmium accumulation capacities of different leafy vegetables through cadmium-rich substrate cultivation

利用穴盘育苗技术,通过设置不同基质镉浓度水平和育苗时间,获得不同叶菜对镉累积能力数据,并与田间条件下相关结果进行比较、验证,探讨通过富镉基质栽培比较叶菜镉累积能力的可行性。结果表明:供试叶菜品种地上部镉含量和生物富集系数(BCFs)值随基质镉浓度和培养时间变化显著。多因素方差分析表明,叶菜品种、育苗天数和基质镉含量以及因素间交互作用对叶菜BCFs均有显著影响,而叶菜品种对总变差的贡献最多,是叶菜BCFs值差异的主导因素,控制着叶菜BCFs值的绝对水平。育苗10 d且基质镉含量1.0 mg·kg^-1条件下,穴盘基质栽培和田间试验中叶菜BCFs的相关系数最大(R2=0.90),且该条件下的聚类分析以及单因素方差分析结果也与田间结果最为吻合,试验结果具有较好的稳定性。表明育苗10 d且基质镉含量1.0 mg·kg^-1条件下富镉基质栽培得到的结果能够相对真实地反映不同叶类蔬菜田间种植时的镉累积能力,可用于今后镉低累积型蔬菜的快速筛选。

To acquire a feasible method for a rapid comparison of the cadmium(Cd)accumulation capacities of different leafy vegetables,using substrate cultivation with different contents of Cd and cultivation time,we compared the observed Cd accumulation capacity with these obtained in the field.The results showed that the Cd content and bio-concentration factors(BCFs)value in the aboveground tissue of leafy vegetable varied significantly with Cd content and cultivation time.Multi-factor analysis of variance showed that vegetable variety,cultivation time,Cd content in substrate and their interaction had significant effects on BCFs of Cd in leafy vegetable.Leafy vegetable variety was the dominant factor affecting BCFs of Cd in leafy vegetable and controlled its absolute level.When Cd content in the substrate reached 1.0 mg·kg^-1 with a cultivation of 10 days,the correlation coefficient of Cd BCFs between the substrate cultivation and field experiments was the highest,with a R2 value of 0.90.The results of cluster analysis and one-way ANOVA had the highest consistence with the field results.Comparatively,the substrate cultivation with Cd content of 1.0 mg·kg^-1 and a cultivation of 10 days showed a good reproducibility and stability in reflecting the difference in Cd accumulation capacities of different leafy vegetable varieties.The Cd-rich substrate cultivation could be used to screen the vegetables with low Cd accumulation and also would promote the field application of the vegetables with low Cd accumulation in the Cd-contaminated area of China.