Seedling responses of four Australian tree species to toxic concentrations of manganese in solution culture

Abstract

Little is known about the responses of Australian plants to excess metal, including Mn. It is important to remedy this lack of information so that knowledgeable decisions can be made about managing Mn contaminated sites where inhabited by Australian vegetation. Acacia holosericea, Melaleuca leucadendra, Eucalyptus crebra and Eucalyptus camaldulensis were grown in dilute solution culture for 10 weeks. The seedlings (42 days old) were exposed to six Mn treatments viz., 1, 8, 32, 128, 512 and 2048 μM. The order of tolerance to toxic concentrations of Mn was A. holosericea ≅ E. crebra < M. leucadendra < E. camaldulensis, the critical external concentrations being approximately 5.1, 5.0, 21 and 3..