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为保证烤烟生产的安全,降低重金属对人体的毒害,对植烟土壤重金属安全临界值进行推算。通过土壤盆栽试验,研究了3个烤烟品种翠碧1号、K326和云烟87对Cd的累积和分配规律,土壤中Cd2+添加量分别为0、0.5 mg/kg、1 mg/kg、2 mg/kg、4 mg/kg、8 mg/kg,并采用回归分析方法计算了植烟土壤Cd的安全临界值。结果表明,烤烟Cd质量比受外源Cd添加量影响较大,下部叶Cd质量比总是高于其他部位。随Cd添加量增大,各部位Cd质量比上升且差别逐渐增大。Cd在土壤-根的转移系数较低,地上部各部位对土壤Cd转移系数的平均值表明,翠碧1号对Cd富集能力略强,而K326较弱。外源Cd的添加导致土壤-下部叶Cd的转移系数达最高,Cd在根-下部叶的转移系数明显高于其他部位间的转移系数,并使Cd在烤烟植株各部位间的转移系数呈先增后降的趋势。烤烟地上部的Cd累积量均高于根部,其中中、下部叶Cd累积量最多,而上部叶较少。经推算得出,烤烟叶片Cd的最高允许质量比为5.79 mg/kg,由烤烟中部叶Cd质量比与土壤有效Cd质量比的回归模型得到,3种烤烟的植烟土壤的安全临界值分别为0.17 mg/kg(翠碧1号)、0.19 mg/kg(K326)和0.15 mg/kg(云烟87),云烟87的土壤安全临界值可以作为制定福建烟区土壤Cd的安全临界值依据。
In order to ensure the safety of flue-cured tobacco production and reduce the toxicity of heavy metals to human beings, the critical value of heavy metal safety of tobacco-planting soil is calculated. The pot experiment was conducted to study the accumulation and distribution of Cd in three flue-cured tobacco cultivars, CuiBi 1, K326 and Yunyan 87. Cd 2+ content in the soil was 0,0.5 mg / kg, 1 mg / kg and 2 mg / kg, 4 mg / kg and 8 mg / kg respectively. The safety critical value of Cd in tobacco soil was calculated by regression analysis. The results showed that the quality of Cd in flue-cured tobacco was more affected by the amount of exogenous Cd than that in other parts. With the increase of Cd content, the mass ratio of Cd in all parts increased and the difference increased gradually. The lower transfer coefficient of Cd in soil-root, the average value of soil Cd transfer coefficient in each part of above-ground part showed that Cui-bi 1 was slightly stronger in Cd accumulation, while K326 was weaker. The exogenous Cd addition resulted in the highest Cd transfer coefficient in soil-lower leaf, the transfer coefficient of Cd in root-lower leaf was significantly higher than that in other parts, and the transfer coefficient of Cd in various parts of tobacco plants was first Increase and then decrease the trend. The accumulative amount of Cd in above-ground parts of flue-cured tobacco was higher than that in the roots, of which, Cd accumulation in middle and lower leaves was the highest while that in upper leaves was less. The highest allowable mass ratio of Cd in flue-cured tobacco leaves was 5.79 mg / kg, which was obtained by regression model of the mass ratio of Cd to the available Cd in the middle leaves of tobacco leaves. The safety critical values of the three kinds of flue-cured tobacco soils were 0.17 mg / kg (CuiBi 1), 0.19 mg / kg (K326) and 0.15 mg / kg (Yunyan 87). The critical value of soil safety of Yunyan 87 could be used as the safety critical value for soil Cd development in Fujian tobacco area.