Coal Dust Reduce the Rate of Root Growth and Photosynthesis of Five Plant Species in Inner Mongolian Grassland

Dust pollution is one of the major environmental problems in opencast mining, which has a significant impact on the surrounding ecosystem. Little is known about the effect of coal dust deposition on plant growth in grasslands, especially on root growth. In this study, we studied how coal dust deposition affected plant growth, with a focus on root growth. Five plants which commonly can be found in Inner Mongolian grassland were selected and cultured with hydroponics methods in greenhouse. Two kind of coal dust (coal powder and granite powder) were sprayed on the plant for 35 days. Root morphology parameters and photosynthesis parameter were determined. We found that among the six measured root morphological characters, root surface area and volume were negatively affected by coal dust in most species. Both coal powder and gangue powder inhibited root growth of four out of five species. Lespedeza davurica was the only species that was not affected by dust pollution. Coal dust can negativly affect the photosynthesis rate. Based on these results, we found that coal dust is harmful for plant growth. The growth of grass with long-term acceptance of coal dust pollution may be threatened, even can not be grow in the contaminated grassland.