This volume presents the proceedings of the Second International Sym posium on Genetic Aspects ofPlant Minerai Nutrition, held in Madison, Wisconsin in 1985. The mechanisms by which plants acquire, transport and utilize essential minerai nutrients are highly complex. The means by which plants either exclude or tolerate ions of metals toxic to plants are equally complex. The first symposium attempted to convene research scientists con cerned with minerai nutrition for the purpose of exploring the kinds of minerai nutrition phenomena identified as being under genetic contro!. The first symposium also placed much emphasis on research to which genetic intervention might be applied. At the second symposium more papers were presented on genetic and breeding research, a long-term objective of the first symposium. The second symposium also included biotic interactions under genetic con trol that either enhanced or impeded ion uptake, e.g. mycorrhizae and nitrogen fixing bacteria. This continuing dialogue is essential for a research area the complexity of which is due to its interdisciplinary nature.