不同品种烟草对重金属积累的动态差异

Dynamic Differences of Heavy Metal Accumulation in Different Tobacco Varieties

为探讨不同品种烟草对重金属的积累规律,采用单因素随机区组设计,通过田间试验方法,测定了不同品种各生育期叶片中的铅、镉、铬、砷和汞含量,并分析了烟草对5种重金属元素的富集系数。结果表明:不同品种烟草对重金属的积累能力不同,铅含量中烟103最高,达0.13mg/kg;红大的镉和铬含量均最高,分别为0.91mg/kg和1.95mg/kg;4个品种的砷含量变异较小,以红大稍高,为0.25mg/kg;汞含量品种间无明显差异,中烟103稍高,为0.025mg/kg。烟草对铅、铬和砷的吸收表现为单峰吸收型,即旺长期最高,此后逐渐降低;对镉的吸收则表现出前期高后期低的双峰吸收型,即团棵期最高,以后则逐步减少,但红大与云203在打顶期又出现吸收高峰,到下部叶采收时迅速下降;对汞的吸收趋势表现为逐步增加,到中部叶采收时达到最高。

To understand the accumulation law of heavy metals in tobacco, a field test was conducted by using single-factor randomized block design to determine the contents of Pb, Cd, Cr, As and Hg in leaves of different tobacco varieties in various growth periods. And the bioconcentration factors of the five elements were measured. The results showed that different tobacco varieties differed in the ability of enrichment of different heavy metal elements. Zhongyan 103 was of the highest Pb content（0.13 mg/kg）, Hongda was of the highest contents of Cd and Cr（0.91 mg/kg and 1.95 mg/kg）, the As content varied little in the four tobacco varieties, which was a little higher in Hongda（0.25 mg/kg）. The Hg content was not significantly different in various tobacco varieties, and it was a little higher in Zhongyan 103. The absorption of Pb, Cr and As belonged to uni-peak-type, which reached the peak in fast growing period and then decreased gradually. While the absorption of Cd belonged to bimodal pattern, which was high in earlier stage and low in later stage. The Cd content reached the highest in resettling stage and then decreased gradually. Nevertheless, the Cd content in Hongda and Yun 203 reached the highest in topping stage and decreased rapidly in the collecting period of lower leaves. The absorption of Hg increased gradually from early stage to maturity, and reached the highest in harvesting time of middle leaves.