Responses of Distichlis spicata (L.) Greene to salinity, nitrogen, and water levels.

摘要

I examined the effects of water, salinity, and nitrogen and plant response for inland saltgrass (Distichlis spicata (L.) Greene) via two greenhouse experiments. The first experiment evaluated the influences of salinity and nitrogen on plant performance using a two-way factorial treatment structure in a randomized block design. The second experiment evaluated the influence of water level in a one-way factorial treatment structure in a randomized block design.;No seeds were produced during either year of my study due to pollen limitation and a paucity of female inflorescences. The unavailability of pollen was caused by nonsynchronous timing of pollen release and stigma receptivity. Differences in the number and timing of the male and female inflorescences indicate that other factors more strongly affected sexual reproduction.;Data on number of ramets, ramet height, biomass, and tissue nitrogen content were evaluated as indicators of vegetative plant performance. Salinity treatment and water-level treatment effects were observed on these response variables during 1995. Nitrogen treatments typically did not affect the response variables.;Based on my results, observations on gender diphasy and shifts in the mode of reproduction, and a review of pertinent literature, I advance an optimal reproductive strategy for D. spicata that suggests that vegetative reproduction, rather than sexual reproduction, is a fitness priority for D. spicata.