关键词: 矿区, 煤矸石山, 丛枝菌根真菌, Cd

Abstract: 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.

Key words: mining area, coal gob piles, arbuscular mycorrhizal fungi, Cd