粉葛对农田土壤镉的富集特征

Accumulation characteristics of cadmium in farmland soil by Pueraria thomsonii

  • 摘要: 选用生长速度快、生物量大、经济价值高的富集植物是重金属生物修复新的突破口。为研究粉葛对农田土壤镉(Cd)的富集特征,采用大田试验探讨3种污染程度下粉葛不同部位葛根(葛粉和葛渣)、葛头、主藤、侧枝和叶片中Cd浓度。结果表明:粉葛不同部位中Cd浓度表现为侧枝(8.96 mg/kg)>主藤(6.85 mg/kg)>叶片(5.22 mg/kg)>葛头(2.80 mg/kg)>葛渣(1.36 mg/kg)>葛根(1.21 mg/kg)>葛粉(0.16 mg/kg),且随土壤污染程度增加而增加,表现为中、高污染显著高于低污染(P<0.05)。除葛根外,粉葛其他部位对土壤Cd的富集系数均大于1(1.09~8.65),转运系数为2.59~8.98。粉葛各部位中Cd的分配率表现为侧枝(35.64%~43.81%)>主藤(21.55%~25.49%)>叶片(15.40%~23.63%)>葛根(7.03%~9.94%)>葛头(5.99%~9.57%)。粉葛各部位生物量表现为葛根>侧枝>叶片>主藤>葛头,粉葛对Cd移除量随土壤污染程度递增,具体为高污染(45.39 g/hm2)>中污染(39.96 g/hm2)>低污染(16.56 g/hm2)。总体上,粉葛各部位中Cd浓度与土壤有机质、有效态Cd、总Cd浓度呈显著正相关,而与土壤pH均呈负相关。在Cd污染农田土壤治理中,粉葛(用作葛粉)对Cd污染农田土壤修复具有应用价值。

     

    Abstract: The selection of rich plants with high growth, high biomass, and high economic value is a new breakthrough in the bioremediation of heavy metals. To study the accumulation characteristic of cadmium (Cd) by Pueraria thomsonii in farmland soil, field experiments were conducted to investigate Cd contents in tuber (radix pueraria and arrowroot), basal part of stem, main vine, lateral branch, and leaf of Pueraria thomsonii under three pollution levels. The results showed that Cd contents in different parts of Pueraria thomsonii were lateral branch (8.96 mg/kg) > main vine (6.85 mg/kg) > leaf (5.22 mg/kg) > basal part of stem (2.80 mg/kg) > radix pueraria (1.36 mg/kg)> tuber (1.21 mg/kg)> arrowroot (0.16 mg/kg). Cd contents increased with the increase of soil pollution, showing that Cd contents in medium and high pollution were significantly higher than in low pollution (P < 0.05). Except for tuber, the accumulation coefficient of Cd in other parts of the plant was higher than 1 (1.09-8.65), and the transport coefficient was 2.59-8.98. The distribution rates of Cd content in various parts of Pueraria thomsonii were as follows: lateral branch (35.64%-43.81%) > main vine (21.55%-25.49%) > leaf (15.40%-23.63%) > tuber (7.03%-9.94%) > basal part of stem (5.99%-9.57%). The biomass in various parts of Pueraria thomsonii was tuber > lateral branch > leaf > main vine > basal part of stem. The removal amount of Cd increased with the pollution level, which was high pollution (45.39 g/hm2) > medium pollution (39.96 g/hm2) > low pollution (16.56 g/hm2). In general, Cd contents in various parts of Pueraria thomsonii were significantly positively correlated with soil organic matter, available Cd, and total Cd, but negatively correlated with soil pH. In the treatment of Cd contaminated farmland soil, Pueraria thomsonii (used as arrowroot) has application value for Cd contaminated farmland soil remediation.

     

/

返回文章
返回