The reproductive ecology of Vallisneria americana: The effect of seed pre-treatment and salinity of germination and the effect of salinity on seedling growth and survival.

摘要

The number of prolific Vallisneria americana beds has declined over the past 30 years. Experiments on how salinity effects Vallisneria seed germination, seedling survival, and seedling growth were conducted to determine the best method of establishing Vallisneria beds in Mobile Bay. Studies revealed no significant difference in the percent germination of seeds in salinities of 0, 2, 4, 6 and 12ppt, although there was a slight decrease in percent germination at 12ppt. Three methods of pre-treating Vallisneria seeds were tested to see which was the best method for stimulating the seeds to germinate. Seed coat abrasion with sand paper showed a significantly higher percent germination than the control (no pre-treatment), the cold shocked or acid shocked treatments. Seedling growth and survival was monitored for 56 days at salinities of 0, 2, 4, 6 and 12ppt. Seedling growth was highest at the lower salinities of 0, 2, and 4ppt. The data presented shows the 6ppt plants had the highest growth at the end of the experiment, however, the smaller plants at this salinity were dying off leaving the tallest seedlings to be measured. Seedling survival was highest in the 12ppt seedlings initially because very few seedlings were actually germinated at this salinity. Seedling survival was highest at the lower salinities of 0-4ppt.