Response of Sporobolus virginicus (L.) Kunthto salinity

Abstract

Optimal growth of euhalophytes requires moderate concentrations of salt and, in dicots, is associated with succulence of leaves and stems and accumulation of Na⁺ in plant tissues. Relative growth rate, water and cation content were studied in Sporobolus virginicus, a C₄ Chlorodoid grass, grown under different concentrations of NaCl. Optimal growth occurred at 100-150 mmol/L NaCl. and was not dependent on nitrogen levels or accompanied by accumulation of Na⁺ in leaves. Na:K ratios were lower in leaves and rhizomes than in roots indicating the possibility of discrimination in Na⁺ and K⁺ transport from roots to leaves. Water content of leaves and shoots was significantly greater in plants grown at optimal levels of salinity than in plants grown at sub or supra optimal salinity. Na⁺ and K⁺ concentrations in leaves contribute approximately 60% of osmolality. These results support the characterization of S. virginicus as a euhalophyte.