Mineral nutrition of the hyperparasitic mistletoe <I>Viscum articulatum</I> Burm. f. (Viscaceae) in tropical Brunei Darussalam

Abstract

A plant parasite parasitizing another plant parasite is known as a hyperparasite. Information is scarce regarding the ecophysiology of hyperparasites and their hosts despite their potential to illuminate processes of host–parasite solute flux. Here we present mineral profiles and stable isotopic data for two associations of the hyperparasite Viscum articulatum and its primary mistletoe and tree hosts. Acting as the terminal sink, the hyperparasite had consistently higher contents of all major and minor elements evaluated compared to the primary parasite and the proximal portion of the tree host branch. The primary parasite had lower contents of Cu, Mg, Mn, N, and Z relative to the proximal portion of the tree host branch, suggesting nutritional stress applied by the hyperparasite. Interestingly Fe and Cu showed no consistent pattern between host and primary parasite, while the osmotically active elements P and K increased from tree host, to primary mistletoe, and finally the hyperparasitic mistletoe. The δ13C partitioning patterns for hyperparasites, primary parasites, and hosts were non-linear in contrast to linear patterns reported from the literature for autoparasitic mistletoe associations, demonstrating fundamental differences between nutrition in hyperparasites and autoparasites.