Chemical composition of guttation fluid and leaves of Petasites japonicus v. giganteus and Polygonum cuspidatum growing on ultramafic soil

Petasites japonicus v. giganteus (Japanese butterbur) and Polygonum cuspidatum (Japanese knotweed) exude a large quantity of guttation fluid from the leaf edge. The concentrations of Ni and Mn in the guttation fluid from Petasites japonicus v. giganteus grown on ultramatic soil were 2.24 (Ni) and 0.32 (Mn) mg L-1, respectively, on the average, whereas those in the guttation fluid from Polygonum cuspidatum were 0.22 (Ni) and 3.13 (Mn) mg L-1, respectively. The Ni concentration in the leaves of Petasites japonicus v. giganteus was about 5 times as high as that of Polygonum cuspidatum, especially at the leaf edges, and the Mn concentration in the leaves of Polygonum cuspidatum was about 6 times as high as that of Petasites japonicus v. giganteus. Thus, the concentrations of Ni and Mn in both the guttation fluid and leaves of Petasites japonicus v. giganteus were opposite to those of Polygonum cuspidatum. The contents of K, Mg, and Ca in the guttation fluid from Petasites japonicus v. giganteus were higher than those in the guttation fluid from Polygonum cuspidatum in the ultramafic rock area.