Abstract
Seed germination is a major factor limiting the establishment of plants under saline conditions. In a field trial, conducted in experimental catchments, in the south west of Western Australia, we found changes in riparian plant species composition and diversity along a salinity gradient. To assess this impact further, the germination responses of eight native plant species, found in these catchments, to various levels of sodium chloride (NaCl) were examined. Experiments were conducted at salt concentrations of 0, 100, 120 and 140 EC1:5 soil conductivity respectively, set at 15oC in a dark incubator. There were eight replicates, each containing ten seeds per treatment. The results showed a significant decline in percentage germination rate in species of Hakea undulata and Hakea varia as salinity increased; an increase in the number of days for the seed radicle to expose as salinity increased; and for several species, a decline in germination response with an increasing percentage of seed viability at the end of the test, as salinity increased.