Ch. Keiffer et Ia. Ungar, THE EFFECT OF EXTENDED EXPOSURE TO HYPERSALINE CONDITIONS ON THE GERMINATION OF 5 INLAND HALOPHYTE SPECIES, American journal of botany, 84(1), 1997, pp. 104-111
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.