Effect of zinc and lead on germination of Spartina alterniflora loisel seeds at various salinities

Abstract

Spartina alterniflora seeds were germinated for 30 days in solutions containing zinc and lead at various salinity levels under chamber-controlled conditions. Daily counts of epicotyl emergence were used to calculate: (1) an initial rate of germination (first 5 days), (2) time for seeds treated with metal and salt to yield 50% of the response of untreated seeds (distilled water treatment) and (3) total germination at the end of the experiment (30 days). Seeds remaining ungerminated after 30 days were put through a series of washings and treatments to remove metal and salinity stresses. The latter was done in an attempt to identify and distinguish between osmotic and toxic effects. Results indicate that lead reduced the germination rate, total performance and long term germination potential after an initial stimulation of germination. Experimental units treated with lead at high salinities produced results indicative of toxic action (non-reversible inhibition). Zinc treatments did not produce results that would indicate any significant action by this metal, except at the lowest salinity level. However, stimulation of germination was induced by zinc treatments and salt-inhibition of germination was altered by zinc additions.