Abstract

This study was conducted to determine the effects of temperature and salinity on seed germination and their recovery of germination after being transferred from saline conditions to distilled water. The germination responses of the seeds in complete darkness were determined over a wide range temperatures (10 to 35°C) and salinities (0 to 500 mM NaCl). Germination was inhibited above or below the optimal temperature of 15°C. The highest germination percentages were under non-saline conditions, and increased NaCl concentrations progressively inhibited seed germination. Germination rate decreased with increased salinity at all temperatures, but the highest rates were at 15°C. The interaction between salinity and temperature yielded no germination at 500 mM NaCl (25 and 35°C). After 10 days, seeds were transferred from salt solution to distilled water, and germination recovered at all temperatures with low salinity. At 500 mM NaCl, there was no germination recovery at25 and 35°C. The results showed that salt stress decreased both the percentage and the rate of germination, exposure to high concentration of NaCl permanently inhibited germination at high temperature.

Key words: Desert ecosystems, Hedysarum scoparium, recovery germination, salinity, temperature, seed germination.