Effect of Soil Salinity on Germination and Survival of Some Steppe Plants in Washington

Salt tolerance at germination and the capacity of the established plants to endure gradual salinization of the soil were studied in Agropyron spicatum, Artemesia tridentata, Elymus cinereus (from saline and non—saline habitats), Lepidium perfoliatum (from saline and non—saline habitats), and Typha latifolia. Percentage germination decreased with increasing salinity. All species were less tolerant of salinity at germination than they were at the seedling stage, if salinization of the culture medium was gradual. An abrupt rise in salinity resulted in death of all species. Of all the species tested Lepidium perfoliatum demonstrated the greatest potential for ontogenetic osmoregulation. In general, the response of the established plants corresponds well with the species behavior in the field. Adverse environmental factors, such as a predominance of Na 2 CO 3 , probably results in restricted distribution of Typha latifolia and also keeps Agropyron spicatum from colonizing saline areas. Seeds of Lepidium perfoliatum from saline habitats were more tolerant of salinity than those from non—saline habitats, indicating an ecotypic specialization in this species. Populations of Elymus cinereus from saline and non—saline habitats did not differ in this respect.