The Eurasian herb Alliaria petiolata (garlic mustard) is an aggressive invader of the North American temperate biome and, particularly, of deciduous forests. A possible reason for its success as an invader is the production of allelopathic secondary metabolites, primarily glucosinolates (e.g. sinigrin and glucotropaeolin) and flavonoids (e.g. alliarinoside), to which native N. American plant species have not been exposed during their evolutionary history. Previous studies have shown that production of both glucosinolates and flavonoids frequently increases in plants that are grown in atmospheric concentrations of CO2 equal to future predicted levels for 2050. We used HPLC (high-performance liquid chromatography) to investigate the total and individual concentration of glucosinolates and flavonoids in tissues of A. petiolata grown at atmospheric concentrations of CO2 equal to 400 ppm and 600 ppm, to determine if this invasive plant may become even more successful in the future.
Results/Conclusions
Preliminary results indicate that total glucosinolate concentration and total flavonoid concentration is significantly higher in tissues of A. petiolata grown in elevated (600 ppm) atmospheric CO2 than in tissues of A. petiolata grown at near ambient (400 ppm) atmospheric CO2. Individual glucosinolates and glucosinolate groups responded variably, with concentrations increasing, decreasing, or remaining unchanged under elevated conditions, depending on the compound or groups examined. Individual flavonoids and flavonoid groups also responded with variability in compound concentration in a similar pattern. These preliminary results indicate that if the invasive success of A. petiolata is due, or partly due, to the production of glucosinolates and flavonoids, then future CO2 concentrations will increase its potential invasiveness.
