Difference of Growth, Copper Accumulation and Mineral Element Uptake in Two Elsholtzia Haichowensis Populations under Copper and Mineral Nutrition Stress

Two Elsholtzia haichowensis populations, one from a copper mine (CS) and the other from an uncontaminated site (UCS), were studied in hydroponic experiments for the plant growth, copper accumulation and mineral nutrients content under excess copper and nutrient deficiency conditions. The results indicated that the CS population had evolved not only Cu tolerance but also tolerance to low nutrient supply. Under Cu treatments, the CS population had less Cu accumulation in roots than the UCS one, suggesting the root exclusion mechanism existing in the former. It was also found that general nutrient deficiency markedly promoted Cu uptake and transport in the two populations. But CS population had less Cu accumulation than UCS population did. Under Cu stress, the CS population had less change in nutrient composition than the UCS one. The similar result was observed in general nutrient deficiency experiment. The results indicated that the mineral composition homeostasis under the stresses was important in metal tolerance and colonizing normally in the Cu-enriched soils for the Cu-tolerant population.