Effect of salinity, light, and temperature on germination in Allenrolfea occidentalis

Abstract

Allenrolfea occidentalis (S. Wats.) Kuntze, a halophytic perennial shrub in the family Chenopodiaceae, is widely distributed in inland salt marshes and salt playas of western North America. Experiments were conducted to determine the effects of NaCl, light, and temperature on seed germination and their recovery of germination from saline conditions after being transferred to distilled water. Seeds of A. occidentalis were germinated at various temperatures (5:15, 10:20, 10:30, 15:25, 20:30, and 25:35°C (night:day)) and salinities (0, 200, 400, 600, 800, and 1000 mM NaCl) in a 12 h light : 12 h dark photoperiod and in 24 h darkness. Increases in NaCl concentration progressively inhibited seed germination, and this inhibition was greater in the dark than in light. No seeds germinated at concentrations higher than 800 mM NaCl. Cooler temperatures significantly inhibited germination in all treatments, while regimes of high night (25°C) and high day (35°C) temperatures showed higher germination. Rate of germination decreased with an increase in salinity. Germination rate was higher at 25:35°C and lower at 5:15°C. Seeds were transferred from salt solutions to distilled water after 20 days, and those from high salinities recovered quickly at all temperature regimes. Recovery germination percentages at higher salinities varied from 51 to 100% at various temperatures, but recovery of germination of seeds from salt stress was significantly affected by temperature regime.Key words: Allenrolfea occidentalis, halophyte, light, recovery of seed germination, salt playas, thermoperiod, Utah.