Arbuscular mycorrhiza of Berkheya coddii and other Ni-hyperaccumulating members of Asteraceae from ultramafic soils in South Africa

The occurrence of arbuscular mycorrhiza (AM) in nickel-(Ni)-hyperaccumulating plants of the Asteraceae family growing on Ni-enriched ultramafic soils in South Africa was surveyed. All plants were found to be consistently colonised by AM fungi, with the abundant formation of arbuscules. Berkheya coddii, which is an important species for phytomining, formed well-developed mycorrhiza under greenhouse conditions. Plants cultivated under greenhouse conditions and inoculated with native fungi had a higher shoot biomass and Ni content than noninoculated plants. Inoculation of B. coddii with Glomus intraradices (BEG) was successful, but only plants with abundantly developed arbuscules showed increased yield. In other cases, shoot biomass was similar to noninoculated plants. Dense depositions localised on top of the arbuscules were often observed in roots collected from the field and from pot cultures.