title: Effects of salinity on growth and cation accumulation of Sporobolus virginicus (Poaceae).
abstract: Optimal growth of euhalophytes requires moderate concentrations of salt and, in dicotyledons, is associated with succulence and accumulation of Na(+) in plant tissues. However, reports of salt-stimulated growth in monocotyledons are rare. Relative growth rate (RGR), biomass accumulation, and water content were studied in Sporobolus virginicus (Poaceae), a C(4) chloridoid grass, grown hydroponically with different concentrations of NaCl. Cation concentrations were determined by atomic absorption spectrophotometry. Optimal growth occurred at 100-150 mmol/L NaCl and was not dependent on nitrogen levels or accompanied by accumulation of Na(+) in leaves. Biomass accumulation and RGR in plants grown at 450 mmol/L NaCl were greater than in plants grown at 5 mmol/L. The Na : K ratios were lower in leaves than in roots, indicating discrimination in Na(+) and K(+) transport. Secretion of Na(+) increased from 166.5 to 336.7 mmol · g(-1) dry biomass · d(-1) as the NaCl concentration of the nutrient solution increased from 125 mmol/L to 450 mmol/L. Water concentrations of leaves and shoots were significantly greater in plants grown at optimal levels of salinity than in plants grown at lower or higher salinities. These results demonstrate salt-stimulated growth in a monocotyledon.
authors.affiliation: The University of Arizona, Department of Plant Sciences, Tucson, Arizona 85721 USA.
authors.forename: Hester L
authors.initials: HL
authors.lastname: Bell
authors.forename: James W
authors.initials: JW
authors.lastname: O'Leary