Effect of soil moisture on the percolation of lichen substances from Cladonia verticillaris (Raddi) Fr. in a quarzarenic neosol from Brazil

Abstract

Cladonia verticillaris (Raddi) Fr. is a lichen species that grows on sandy soil of tablelands coexisting with savannah-like vegetation in Brazil. This species produces different lichen phenolics that are leached to the soil by the rainwater and exhibit several biological activities that could affect the habitat. The effect of soil moisture in the retention and percolation of proteins, protocetraric acid (PRO) and fumarprotocetraric acid (FUM), the main phenolics produced from C. verticillaris, was analyzed in this work. Proteins were retained in dry soil but they percolated when the soil was water-saturated. FUM was strongly retained in this kind of acidic soils and transformed into PRO by spontaneous hydrolysis when the soil moisture increased. This study demonstrates that proteins, PRO and FUM that were effectively leached to the soil, retained, transformed or percolated to deeper soil layers depending on the amount of previous rainfall. This fact must be taken into account in order to consider the biological effects of these substances on the vegetation of coastal tableland Brazil.