Most parasitic plants do not form mycorrhizal associations and hence the nutritional role of arbuscular mycorrhizal (AM) fungi in them has not been ascertained. Using 32P-labelling in compartmented pots, Li et al. study the facultative root hemiparasitic species Pedicularis rex and P. tricolor and find that AM colonization is low, and less than 1 % of total plant P is taken up from the soil via the AM fungus. Inoculation with AM fungi strongly interferes with P acquisition by both species from their host plant, barley, and this is almost certainly because the numbers of haustoria formed by the parasite are significantly reduced in AM plants.
AM fungi and P acquisition by hemiparasitic Pedicularis
A study of Pedicularis rex and P. tricolor finds that AM colonization is low, and less than 1 % of total plant P is taken up from the soil via the AM fungus.