The effects of density and salinity on shoot biomass and ion accumulation in five inland halophytic species

摘要

Five inland halophytes,Atriplex prostrata,Hordeum jubatum,Salicornia europaea,Spergularia marina, andSuaeda 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 plants∙100ensp;cmminus;2) to determine the effects of salinity and density on survival, growth, and ion accumulation. The more salt sensitive species,A.prostrataandH.jubatum, had significant (Pensp;ensp;0.05) density-dependent mortality. Density significantly reduced biomass production for all species, except forH.jubatumin the high-salinity treatment. Succulence inSuaeda calceoliformisshoots increased in the high-salinity treatment, butH.jubatumplants were desiccated at the time of harvest. The ash, sodium, and chloride contents of shoots increased with salinity for all species. Sodium and Clminus;ion contents for all species ndash;treatment combinations were an order of magnitude higher than that of Mg2+, Ca2+, and K. AlthoughA.prostrata,Salicornia europaea, andSuaeda calceoliformisaccumulated similar levels of Na+in their shoots,Suaeda calceoliformisplants from the two higher densities in the low-salinity treatment accumulated twice as much total Na+per pot thanA.prostrata, and seven times more Na+thanSalicornia europaea. Based on these laboratory studies,Suaeda calceoliformisplanted in densities ranging from 15 to 30 plants∙100ensp;cmminus;2would accumulate more Na+from saline-contaminated soils than the other species.Key words: bioremediation,Atriplex, Hordeum,Salicornia,Spergularia,Suae