Chemical composition of prince feather leaves : A geochemical indicator of organic matter in the fluvial sediment

Abstract

Leaf samples were taken from prince feather (Polygonum orientate L.) and a related species (Polygonum mitts Gilibert var. Nemoto) growing on the river beach of the Tamagawa River, Tokyo. Dried samples were chemically analyzed with the results shown in Table 2. A high manganese content found in some of the samples revealed the availability of the element in the swampy ground on which the plant grows. This is due to the reducing environment produced by organic matter in the sediment. Under reducing conditions, manganese is released as divalent ion and uptaken by plants. Organic matter also behaves as chelating agent toward many heavy metal ions. The leaf samples enriched in manganese often show high copper and zinc contents, thus indicating the accumulation of heavy metals in the soil. The mananese content of the plants may be useful as a geochemical indicator characterizing organic matter in the fluvial sediment and the soil.