BELL, HESTER L.1,2* and JAMES W. O'LEARY1. 1University of Arizona, Department of Plant Sciences, Tucson, AZ 85721; 2current: Rancho Santa Ana Botanic Garden, 1500 N. College Ave., Claremont, CA 91711. - Response of Sporobolus virginicus (Poaceae) to salinity.
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 (L.) Kunth, 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.
Key words: Sporobolus virginicus , euhalophyte, grass, Na:K ratio, salinity