Great Basin Naturalist


Triglochin maritima L. (arrow grass), an herbaceous perennial in the family Juncaginaceae, is widely distributed in inland and coastal salt marshes of North America. Triglochin maritima seeds from a population growing in a salt marsh at Faust, Utah, were germinated at 4 temperature regimes (12-h night/12-h day, 5–15°C, 5–25°C, 10–20°C, and 15–25°C) and 5 salinities (0, 100, 200, 300, 400, and 500 mol m−3 NaCl) to determine optimal conditions for germination and level of salt tolerance. Ungerminated seeds were returned to distilled water after 20 d to determine whether seeds could recover from salinity treatments. Maximum germination occurred in distilled water, and increases in NaCl concentration progressively inhibited seed germination. No seeds germinated at concentrations higher than 400 mol m−3 NaCl. A temperature regime of low night (5°C) and high day (25°C) temperature yielded maximum germination; all other temperature regimes significantly inhibited seed germination relative to this optimum. Recovery of germination was highest at 5–25°C and lowest at 5–15°C. Recovery of seed germination when seeds were transferred to distilled water from salt solutions was highest at 5–25°C (72%) for seeds exposed to the 500 mol m−3 NaCl pretreatment and significantly reduced at other temperature regimes. The recovery germination response indicates a synergistic inhibitory interaction effect on germination when seeds were exposed to high salinities at suboptimal thermoperiods.