Biological Cycles of Mineral Elements in a Young Mixed Stand in Abandoned Mining Soils Effect of modification treatments on behaviour of heavy metals in combined polluted soil Tissue Distribution of 6 Kinds of Transport Heavy Metal Pollutants in Platanus hispanica Leaves and Annual Branches Formation of iron plaque on root surface and its effect on plant nutrition and ecological environment Determination on residues of several heavy metal elements in Panax notoginseng and its cultivating soil