Seasonal Flux of Nonstructural Carbohydrate in Five Species of Submerged Macrophytes in a Precambrian Shield Lake. Part 1: Effect of Light and Water Depth

Abstract

AbstractSummary: Soluble carbohydrate and starch were examined in shoots of Ceratophyllum demersum, Elodea canadensis, Myriophyllum exalbescens, Potamogeton foliosus and P. zosteriformis in Shoal Lake (Manitoba–Ontario) during the 1985 season. A wide range of variation was found for the same species on any given day among different sampling stations at the same depth. Correlations of each of total soluble carbohydrate and starch with water depth were inconsistent on any given day, although inverse correlations were more common. In M. exalbescens, roots consistently contained more soluble carbohydrate than shoots. The soluble carbohydrate fraction of all species contained glucose, fructose and sucrose. However C. demersum also contained significant and relatively constant proportions of melibiose, raffinose and stachyose. Starch content decreased during the season in C. demersum but increased in P. foliosus and P. zosteriformis shoots. E. canadensis and M. exalbescens showed no significant seasonal trends. Starch comprised 30 … 85 % of the total nonstructural carbohydrate in the 5 species. Seasonal carbohydrate and starch concentrations were not significantly correlated with each other in any of the macrophytes examined. The proportion of starch relative to the total nonstructural carbohydrate increased during the season in P. foliosus and P. zosteriformis.