Effect of mercury and cadmium on germination of Spartina alterniflora Loisel seeds at various salinities

Abstract

Spartina alterniflora seeds were germinated in solutions containing mercury or cadmium at various salinity levels for 30 days under controlled conditions. Daily counts of epicotyl emergence were used to calculate an intial rate of germination (first 5 days), time for seeds treated with metal and salt to yield 50% of untreated seeds (distilled water treatment) and 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. This was done in such a way so that osmotic and toxic effects could be identified. Results indicated both mercury and cadmium reduce the germination rate, total performance and long-term viability after an initial stimulation of germination. Increases in the detrimental effect were directly correlated with increases in salinity level and metal concentration. Findings also indicate some salt (possibly chloride ion) toxicity to S. alterniflora seeds.