Seed germination characteristics of Halogeton glomeratus

Halogeton glomeratus (Bieb.) C.A. Mey, an annual forb in the family Chenopo diaceae, is widely distributed in the inland salt deserts of western North America. Experiments were conducted to determine the effects of NaCl and te mperature on seed germination and the recovery of germination responses aft er transfer to distilled water. Seeds of H. glomeratus were germinated at v arious temperature regimes (5-15 degreesC, 10-20 degreesC, 10-30 degreesC, 15-25 degreesC, 20-30 degreesC, and 25-35 degreesC), and salinities (0, 200 , 400, 600, 800, and 1000 mM NaCl) in a 12 h dark : 12 h light photoperiod. Increases in NaCl concentration progressively inhibited seed germination, and this inhibition was more substantial in the dark than in the photoperio d treatment. Seed germination at concentrations higher than 800 mM NaCl was low (10%). Cooler temperatures significantly inhibited germination in all treatments. A temperature regime of high night (25 degreesC) and high day ( 35 degreesC) temperatures led to higher germination. Rate of germination de creased with an increase in salinity and was highest at 25-35 degreesC and lowest at 5-15 degreesC temperature regimes. Seeds were transferred from sa lt solution to distilled water after 20 days, and those from high salinitie s recovered quickly at all temperature regimes. Recovery germination percen tages from the highest salinity treatment varied from 51 to 100% at various temperature regimes.