THE EFFECT OF EXTENDED EXPOSURE TO HYPERSALINE CONDITIONS ON THE GERMINATION OF 5 INLAND HALOPHYTE SPECIES

In order to determine how salinity and exposure time affect seed viabi lity and germination, seeds of five halophytes, Atriplex prostrata, Ho rdeum jubatum, Salicornia europaea, Spergularia marina, and Suaeda cal ceoliformis were exposed to 3.0, 5.0, and 10.0% NaCl solutions for 30, 60, 90, 365, and 730 d. Recovery experiments in distilled water indic ated significantly different species responses to salinity over time. Percentage germination and rate of germination in H. jubatum were dram atically reduced following extended exposure and all seeds exposed to 10% NaCl for > 1 yr failed to germinate. Spergularia marina seeds were stimulated following short-term exposure to 3% NaCl; however, germina tion was delayed and overall germination was significantly reduced wit h exposure time in the two higher salinity levels. Percentage germinat ion in A. prostrata decreased over time, but salinity level was not re lated to this reduction. Germination of S. europaea and S. calceolifor mis, the most salt-tolerant species being tested, was stimulated by ex posure to high salinity. Both species had a significant increase in pe rcentage germination and in the germination rate when compared to seed s germinated in distilled water. Baseline germination data from seeds placed in 0, 1, 2, and 3% NaCl solutions indicated that S. europaea an d S. calceoliformis were the only species to germinate in the 3% NaCl solution. Spergularia mar ina failed to germinate in the 2% NaCl treat ment, and germination of A. prostrata and H. jubatum was significantly reduced at this salinity level. It is concluded that prolonged exposu re to saline solutions can inhibit or stimulate germination in certain species, and the resulting germination and recovery responses are rel ated to the duration and intensity of their exposure to salt in their natural habitats.