. Nickel
Nickel standing stock seasonal pattern in P. arundinacea (Fig. 4)
exhibited the highest values in the beginning of the growing
season in May (1.62 mg m2
). The standing stock values then
dropped down throughout the summer and then remained more
or less steady until March 2012. Tyler (1971), however, observed a
steady increase in nickel standing stock in several wetland plants
in Sweden during the period March–November. The maximum
value observed in our study was comparable with values reported
for P. australis by Lesage et al. (2007b) from a hybrid constructed
wetland Zevergem, De Pinte in Belgium, but lower if compared to
the value reported by Vymazal et al. (2010b) for P. arundinacea in a