The salt tolerance of irrigated Jerusalem artichokes (Helianthus tuberosus L.) was assessed in terms of biomass of both above ground parts and tubers in greenhouse and field trials. Salinity of irrigation water ranged from 0.7 to 12 dS m-1 in the greenhouse trial and from 0.2 to 10 dS m-x in the field trial. Yield response of the dry matter of tubers of greenhouse-grown plants and of above ground parts of greenhouse-grown and fieldgrown plants, fell within the moderately tolerant category of Maas and Hoffman (1977). However, tuber yields in the field on a heavy clay loam fell within the moderately sensitive category, described by the equation, Y = 100-9.62 (ECe-0.4), where Y=yield (t ha -x) as a % of that under non-saline conditions and ECe = electrical conductivity of saturation extract in the rootzone (0-30 cm). The C1 concentration of leaves increased linearly with increasing external salinity and increased from tubers to stems to leaves. In contrast, leaf Na remained low except at the highest salinities, despite consistently higher stem Na; indicating some mechanism for restriction of leaf Na up to a certain external salinity. --1.86 --2.19 --2.78 -2.93 --4.19 <0.001 0.52 r~lo o MPa --1.35 --1.58 --1.72 --2.27 --2.37 -3.44 <0.001 0.43 sign. = significance (p value) of linear (1.) and quadratic (q.