Differences of Cu accumulation and Cu-induced ATPase activity in roots of two populations of Elsholtzia haichowensis Sun

Two populations of Elsholtzia haichowensis, which are from an uncontaminated site (Hong'an) and a Cu mine site (Tonglushan) in Hubei province, China, were studied for ATPase activities and Cu accumulation of roots under hydroponic conditions. The root tolerance indices were markedly higher in Tonglushan population than in Hong'an population under Cu stress conditions. The root Cu concentration in Tonglushan population was significantly lower than that in Hong'an population in all Cu treatments. The Cu-stimulated ATPase activity increased significantly under 1 μM Cu, reached a peak at 5 μM Cu and then, began to decrease. However, no significant change of ATPase activity was observed in Hong'an population except for an obvious decrease in 80 μM Cu treatment. These results showed that Cu-ATPase might exist in the root plasma membrane of Tonglushan population and play a possible role in resistance to copper.