Influence of Parasitism by Pilostyles ingae (Rafflesiaceae) on its Host Plant, Mimosa naguirei (Leguminosae)

Abstract

Mimosa naguirei (Leguminosae) is parasitized by Pilostyles ingae (Rafflesiaceae) in the Serra do Cipó, in southeastern Brazil. The study examined the influence of this parasite on various parameters of M. naguirei in an attempt to establish general patterns for future research. It was found that the percentage of parasitized plants varied along an altitudinal gradient of 500 m. The parasitic plant influenced the architecture of the host plant. The number of branches on parasitized plants was significantly greater than the number of branches on non-parasitized plants. Branches of parasitized plants were significantly shorter than branches on non-parasitized plants. The density of P. ingae flowers decreased from the stem base to apex. The number of fruits produced by parasitized plants was not greater than the number of fruits produced by non-parasitized plants, although parasitized plants produced smaller fruits and lighter seeds. Seed germination did not differ significantly between parasitized and healthy plants. Copyright 1994, 1999 Academic Press