Associations between site characteristics and plant biomass and starch content of Myriophyllum Spicatum L. in Melton Hill Reservoir

The associations between site characteristics, consisting of both water column and sediment qualities, and total plant biomass and starch content of Myriophyllum spicatum L. was investigated.

Plant and sediment samples were collected monthly from May to September, 1979 in Melton Hill Reservoir near Oak Ridge, TN, U.S.A. Monthly water column data from each site consisted of surface temperature, conductivity and Secchi disk transparency. Sediment samples were analyzed for soil texture, NO₃, available P, available K, organic matter content and pH. Plant samples were analyzed for dry weight, ash content and starch content. Multivariate statistical analyses were used to associate biotic and site variables.

Site variables for two sites located above the Bull Run Steam Plant in the main channel of the reservoir, although statistically significantly different, tended to be similar. Site variables for two sites located below the Bull Run Steam Plant in the main channel of the reservoir, although statistically significantly different, tended to be similar. One site, located in an embayment outside the main channel of the reservoir, had site variables completely distinct from the main channel sites.

Plant biomass at each site was greatest in the shoots, secondly in the roots and lowest in the rhizomes. Seasonal patterns of growth were generally apparent for the shoots, less so for the roots but not apparent for the rhizomes. Root: shoot ratios indicated that most of the plant growth occurred in the shoots. Starch content of plant samples collected at each site throughout the season was greatest in the rhizomes, roots and shoots, respectively. Rhizomes may function as organs for starch storage. Total biomass and total starch content were greatest at the embayment site.

Patterns revealed by canonical correlation analysis associated water surface temperature and Secchi disk transparency with biomass change and starch content in this study.