Heavy metal accumulation and caloric value characteristics in two populations of Potentilla griffithii var. velutina
长柔毛委陵菜两个种群对重金属富集和热值的影响

Concentrations of heavy metals and caloric values as well as their correlation relationship in two populations of Zn hyperaccumulator Potentilla griffithii var. velutina grown in two different sites, Beichang and Paomaping which located in Jinding Pb/Zn mining area, Yunnan Province, were analyzed. The results showed that in Beichang population, Zn concentration (mg kg-1 of dry weight) reached 6217.05 in leaves, 7679.86 in leafstalks and 4455.44 in roots and it was 3.2, 2.4 and 2.2 times of Paomaping population, respectively; Similarly, Cd concentration in Beichang population was 170.17, 242.51 and 244.45 mg kg-1 in leaves, leafstalks and roots, respectively, which was 3.0, 2.2 and 1.9 folds as much as those in Paomaping population, respectively. However, Pb concentration (mg kg-1, DW) in Paomaping population which got 1042.49 in leaves, 829.27 in leafstalks and 2621.39 in roots were a little higher than those in Beichang population. Data showed that the concentration of Zn, Pb and Cd in both Beichang and Paomaping population was related to the concentration of heavy metals in soil. There was no significant difference in capacity of heavy metal translocation and bioaccumulation between these two populations. Both of them showed the same heavy metals translocation capacities which followed by the order of Zn>Cd>Pb. These two populations had no significant difference in ash content and ash-free caloric values in plant tissues. Ash content in roots accounted for smallest part in whole plant, which was less than 6%. Whereas leaves showed the highest caloric values in whole plant, which ash-free caloric value was up to 19.03 and 19.57 kJ g-1 in Beichang and Paomaping population, respectively. In addition, energy storage of P. griffithii var. velutina was facilitated by iron and manganese.