改良剂对土壤重金属(Cd、Pb)的固定以及对烤烟生长影响

Cadmium and Lead immobilization by applying amendments in polluted soils and their effects on tobacco(Nicotiana tabacum) growth

为了从源头减少烟草重金属对人类健康的潜在危害,通过盆栽试验,研究不同改良剂(凹凸棒土、活性炭、有机肥)对植烟土壤重金属(Cd、Pb)的原位固定以及其对烤烟重金属(Cd、Pb)吸收量和生长的影响。分析数据表明:与对照相比,改良剂使得土壤中二乙烯三胺五乙酸(DTPA)提取态Cd与Pb含量有着不同程度的减少,同时,改良剂抑制了烤烟对Cd和Pb的吸收,降低了叶片中Cd、Pb的含量;同时,烤烟由根向叶中转移Cd的能力大于Pb;土壤中DTPA提取态Cd与Pb的含量与烟叶中Cd、Pb的含量呈正相关,表明烟叶中Cd、Pb含量的降低是由于土壤中重金属的有效性下降所致;改良剂处理的土壤上烟叶叶绿素仪测定(SPAD)值与对照相比呈上升趋势,植株根系、高度、叶面积以及叶干重的增加,表现为改良剂降低了重金属对烤烟的毒害,促进了烤烟的生长。此外,随着改良剂剂量的增加,表现出的正面效益越明显。简而言之,3种改良剂增加了烟叶产量并且提高了健康质量。

In order to reduce heavy metals in tobaccos, a pot experiment was conducted to investigate the effects of soil amendments （Attapulgite, Activated carbon, Organic fertilizer） on Cadmium （Cd） and Lead （Pb） immobilization and growth of tobacco. Results showed that DTPA-extractable Cd and Pb in soils were reduced to different degrees by these three soil amendments compared to control treatment. Amendments in the soils reduced uptake and hence Cd and Pb concentrations in roots and leaves. Higher transportation index of Cd in leaves compared to Pb indicated that it was of importance to reduce Cd uptake. DTPA-extractable Cd and Pb in soils were positively correlated to metal concentrations in tobacco leaves suggesting that DTPA-extractable Cd and Pb in soils may be a feasible method to estimate Cd and Pb availability to tobacco plants and the reduction in leaf Cd and Pb concentration was due to a reduction in metal availability to tobacco. A upward trend of leaf SPAD value was observed when plants were grown in soils with all soil amendments compared with control. The addition of amendments resuhed an increase in root length, shoot length, leaf area, and leaf dry weight, indicating important role of soil amendments in protection against Cd and Pb toxicity. Furthermore, higher doses of amendments used resulted in better effects. In general, soil amendments were effective in improving tobacco yield and quality.