THE EFFECTS OF DENSITY AND SALINITY ON SHOOT BIOMASS AND ION ACCUMULATION IN 5 INLAND HALOPHYTIC SPECIES

Five inland halophytes, Atriplex prostrata, Hordeum jubatum, Salicorni a europaea, Spergularia marina, and Suaeda calceoliformis, were grown in controlled laboratory conditions under three salinity treatments (0 .5, 1.5, and 2.5% NaCl) and three density treatments (5, 15, and 30 pl ants . 100 cm(-2)) to determine the effects of salinity and density on survival, growth, and ion accumulation. The more salt sensitive speci es, A. prostrata and H. jubatum, had significant (P < 0.05) density-de pendent mortality. Density significantly reduced biomass production fo r all species, except for H. jubatum in the high-salinity treatment. S ucculence in Suaeda calceoliformis shoots increased in the high-salini ty treatment, but H. jubatum plants were desiccated at the time of har vest. The ash, sodium, and chloride contents of shoots increased with salinity for all species. Sodium and Cl- ion contents for all species- treatment combinations were an order of magnitude higher than that of Mg2+, Ca2+, and K. Although A. prostrata, Salicornia europaea, and Sua eda calceoliformis accumulated similar levels of Na+ in their shoots, Suaeda calceoliformis plants from the two higher densities in the low- salinity treatment accumulated twice as much total Na+ per pot than A. prostrata, and seven times more Na+ than Salicornia europaea. Based o n these laboratory studies, Suaeda calceoliformis planted in densities ranging from 15 to 30 plants . 100 cm(-2) would accumulate more Na+ f rom saline-contaminated soils than the other species.