Spatial and temporal changes in non-structural carbohydrate reserves in eelgrass (Zostera marina L.) in Danish coastal water

摘要

The spatial and seasonal changes of total non-structural carbohydrate (TNC) reserves in above- and belowground tissues in eelgrass (Zostera marina) were assessed at four different sampling sites in Danish waters. The study consisted of annual field sampling, where sites differed in water depth and nutrient content in sediments. The TNC concentrations varied considerably in all tissues, and rhizomes generally represented the major storage organ. Sucrose was the main sugar contributing to TNC whilst starch represented the minor (<15%) reserves. Trehalose, which is reported in Z. marina here for the first time, due to the use of a recently developed HPLC method, was found in low concentrations (up to a142%) and showed a reverse seasonal variation compared to other sugars, with maximum concentrations in winter. Plants growing near depth limits (5.5 m) had significantly higher reserves, whereas no significant effect of sediment nutrient contents on the TNC concentrations was observed, reflecting the ability of Z. marina to tolerate a range of different growth conditions.