石灰、硅酸钠和羟基磷灰石对烟草吸收镉的影响

Effects of Slaked Lime,Sodium Silicate and Hydroxyapatite on Cadmium Accumulation in Tobacco Plant

为了探讨施用不同钝化剂对烟草吸收富集镉的效果,采用盆栽试验研究了石灰、硅酸钠和羟基磷灰石对Pb-Cd复合污染土壤上的烟草镉吸收富集的影响。结果表明,土壤pH值均随3种钝化剂用量的增大而升高,而土壤有效镉(DTPA-提取)含量则随之降低。土壤有效镉的最大降幅分别为:32 g/kg羟基磷灰石处理(52.4%)>16 g/kg石灰处理(37.0%)>12.5 g/kg硅酸钠处理(14.1%)。3种钝化剂都降低了烟株各部位镉的含量,其对烟叶镉含量的平均最大降幅分别为87%(16 g/kg石灰处理),74.7%(12.5 g/kg硅酸钠处理)和82.2%(32 g/kg羟基磷灰石处理)。石灰和羟基磷灰石对镉在根-茎之间的转移无显著影响,而硅酸钠则显著降低了镉在根-茎之间的转移。综上,镉污染的植烟土壤可以施用这些钝化剂以降低烟叶中镉的含量。

A pot experiment using Pb-Cd contaminated soil amended with different levels of slaked lime, sodium silicate and hydroxyapatite was carried out in order to study the effects of the amendments on the uptake and accumulation of Cadmium （Cd） in tobacco. The results showed that soil pH increased while DTPA-extractable Cd of the soils decreased with increasing rate of the amendments. The maximum decrease in DTPA-extractable soil Cd was 52.4% （32 g/kg hydroxyapatite）, 37.0% （16 g/kg slaked lime）, and 14.1% （12.5 g/kg sodium silicate）, respectively. Cadmium contents in various parts of tobacco plants were reduced by the application of the amendments and the average maximum decrease of Cd content in tobacco leaves were 87% （16 g/kg slaked lime）, 74.7% （12.5 g/kg sodium silicate）, and 82.2% （32 g/kg hydroxyapatite）, respectively. Slaked lime and hydroxyapatite did not show significant effects on the transfer of Cd between roots and stems whereas sodium silicate significantly decrease the root-stem transfer of Cd. Therefore, it is concluded that the three amendments could be used to reduce Cd concentration in tobacco leaves.