PARENT SESSION
Poster Session #13: Salt Marshes.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Salt stimulation and tolerance in the intertidal stem succulent halophyte Arthrocnemum macrostachyum.

Khan, M. Ajmal², Ungar, Irwin^*,1, ² University of Karachi, Karachi, Pakistan¹ Ohio University, Athens, Ohio

ABSTRACT- Salt tolerance of Arthrocnemum macrostachyum, a stem succulent halophyte most commonly found in salt marshes of the intertidal regions in the provinces of Sind and Balochistan, Pakistan, was investigated. Plants were grown for 125 days at six NaCl concentrations, from 0 to 1000 mM NaCl, in order to determine the effects of salinity on ion accumulation, plant water status and biomass production. Shoot biomass production was greatest at 200 to 400 mM NaCl, but biomass production was inhibited at salinities of 600 mM NaCl or higher. Tissue water content (grams per gram dry weight) of shoots was higher than controls in 200 to 600 mM NaCl treatments, equal to control in 800 mM NaCl but significantly lower than all other treatments in 1000 mM NaCl, indicating an increase in shoot succulence at salinity levels up to that of seawater. Ash content was about 60% of plant dry mass in all salinity treatments. The Na⁺ and Cl^- concentrations of shoots were 10-fold higher in 1000 mM NaCl than in the control treatment. Our results indicated that A. macrostachyum is salt tolerant and it behaved as a salt includer species, since plants were capable of accumulating a large amount of Na⁺ and Cl^- when they were treated with 200 to 1000 mM NaCl.

KEY WORDS: salt marsh, halophyte, growth, salinity