Influence of salinity and temperature on the germination of Kochia scoparia

Kochia scoparia is one of the most common annual halophytes found in the Great Basin. Seeds were collected from a population growing in a salt playa at Faust, Utah and were germinated at 5 temperature regimes (12 h night/12 h day, 5-15 °C, 10-20 °C, 15-25 °C, 20-30 °C and 25-35 °C) and 6 salinities (0, 200, 400, 600, 800 and 1000 mM NaCl) to determine optimal conditions for germination and recovery of germination from saline conditions after being transferred to distilled water. Maximum germination occurred in distilled water, and an increase in NaCl concentration progressively inhibited seed germination. Few seeds germinated at 1000 mM NaCl. A temperature regime of 25 °C night and 35 °C day yielded maximum germination. Cooler temperature 5-15 °C significantly inhibited seed germination. Rate of germination decreased with increase in salinity. Germination rate was highest at 25-35 °C and lowest at 5-15 °C. Seeds were transferred from salt solutions to distilled water after 20 days and those from high salinities recovered quickly at warmer temperature regimes. Final recovery germination percentages in high salt treatments were high, indicating that exposure to high concentration of NaCl did not inhibit germination permanently.