The First Information on the Low Molecular Metabolome Lobelia dortmanna (Campanulaceae, Magnoliophyta) Growing in Northwestern Russia

The low molecular weight metabolome (LMWM) of Lobelia dortmanna L. (Campanulaceae, Magnoliophyta)—a relic aquatic macrophyte listed in the Red Data Books of the Russian Federation and the Republic of Belarus—has been studied for the first time using the GC/MS technique. This macrophyte grows in oligotrophic lakes in the northwest of Vologda oblast, Russia. We have discovered 127 volatile low molecular weight organic compounds (VOCs), and 13 of the main ones accounted for 77.23% of the overall VOC content (198.75 µg/g of dry plant mass). The main components of the LMWM are represented by carboxylic acids and hydrocarbons. The presence of a large number of biologically active metabolites with a high concentration in L. dortmanna LMWM may indicate a significant effect of this plant on the hydrobiocenoses of the littoral zone of oligotrophic lakes. Further research into the LMWM of aquatic macrophytes in oligotrophic lakes, a valuable renewable resource, is needed to assess the background characteristics of the natural environment for the more effective monitoring of the ecological status of water bodies in northwestern Russia and rational use of their biological resources.