峰峰矿区煤矸石山周边植物丛枝菌根真菌的侵染及Cd含量研究

研究了峰峰五矿、九龙矿、梧桐庄矿煤矸石山周边植物被丛枝菌根真菌侵染的情况,并采用石墨炉原子吸收分光光度法分别测定了植物和土壤中Cd的含量,通过计算转移系数和富集系数比较分析了它们对Cd的富集能力。结果表明:3个矿的煤矸石山周边共发现7科19属20种植物,分别是禾本科、菊科、桑科、萝藦科、藜科、蓼科和苋科植物,其中禾本科植物狗尾草数量最多。3个矿的植物均被丛枝菌根真菌侵染,形成菌根共生体,大多数植物侵染率和泡囊率均较低,狗尾草和萝藦的3个矿平均侵染率较高,狗尾草最高,为59.22%。3个矿的土壤中Cd含量大体相近,平均在1.778~2.066 mg·kg^-1,但植物地上部和地下部Cd含量差异较大。从植物地上部Cd含量来看,五矿和梧桐庄矿均为猪毛蒿最高,分别达到0.863和0.536 mg·kg^-1,含量最低的是虎尾草和马齿苋,仅为0.253和0.203 mg·kg^-1,前者分别是后者的3.41和2.64倍,差异显著。九龙矿中植物地上部Cd含量最高的是狗尾草,达到0.913 mg·kg^-1,显著高于其他植物,是含量最低的狗牙根的7.94倍。从植物地下部Cd含量来看,3个矿最高的均为狗尾草。从转移系数和富集系数来看,3个矿植物的转移系数均高于自身的富集系数,有些植物的转移系数超过1,但富集系数均小于1,其中,猪毛蒿和苦荞麦的转移系数较高,而富集系数则是猪毛蒿和狗尾草较高。优势植物的相关性分析得出丛枝菌根真菌的侵染促进了狗尾草根部从土壤中吸收富集Cd,从而有利于对重金属污染土壤的修复,为利用本土优势植物-丛枝菌根真菌修复重金属污染土壤提供参考。

Arbuscular mycorrhizal fungal infection rates of flora of the Fengfeng mining area coal gob piles and influence on plant Cd content

This research studied arbuscular mycorrhizal fungus infection rates in plants and soil collected from the coal gob piles at the Fifth, Jiulong and Wutongzhuang mines in the Fengfeng mining area, and the Cd levels measured using graphite furnace atomic absorption spectrophotometry. The Cd enrichment ability was also compared by calculating transport and enrichment coefficients. There were 20 plant species belonging to 19 genera and 7 families around the coal gob piles at the three mines. The plant families present were: Gramineae, Asteraceae, Moraceae, Asclepiadaceae, Chenopodiaceae, Polygonaceae and Amaranthaceae. Setaria viridis was the most commonly occurring species. All plants at the three mines were infected by arbuscular mycorrhizal fungi, and formed mycorrhizal symbioses but the fungal mycelium and vesicle densities were low for the majority of plants. The species with the highest average infection rate for the three mines was S. viridis (59.22%) and the second highest was Metaplexis japonica. The Soil Cd concentrations at the three mines were similar, ranging from 1.778 to 2.066 mg·kg^-1 on average. Plant Cd content differed between aboveground and underground plant organs. For aboveground herbage of plants from the Fifth and Wutongzhuang mines, the highest Cd content was observed in Artemisia scoparia (0.863 and 0.536 mg·kg^-1, respectively) and the lowest Cd content was in Chloris virgata and Portulaca oleracea (0.253 and 0.203 mg·kg^-1, respectively, for the two mines). Therefore the highest plant Cd concentrations were 3.41 times and 2.64 times the lowest, respectively, at the two mines. The plant aboveground herbage Cd concentration at the Jiulong mine was highest in S. viridis (0.913 mg·kg^-1), and this was significantly higher than that of other plants, and was 7.94 times higher than herbage Cd concentration in Cynodon dactylon which had the lowest Cd content. The content of Cd in the underground organs of plants from three mines was the highest in S. viridis. The belowground to aboveground transfer coefficients of the plants from the three mines were higher than their own enrichment coefficients. The transfer coefficient of some plants reached or even exceeded 1, but the enrichment coefficients were all less than 1. For the three mines, the transfer coefficients of A. scoparia and Fagopyrum tataricum were highest, while the enrichment coefficients of A. scoparia and S. viridis were higher than those of other plants. A correlation analysis showed that arbuscular mycorrhizal fungal infection promoted the absorption and enrichment of Cd from the soil by the roots of S. viridis. Arbuscular mycorrhizal fungi were therefore beneficial to the remediation of heavy metal contaminated soil. This study thus provides reference data for repair of soil heavy metal pollution coal gob piles in the Fengfeng coal mining area, using locally dominant plant species and arbuscular mycorrhizal fungi to enhance Cd absorption.