Chemical profile of the North American native Myriophyllum sibiricum compared to the invasive M. spicatum

Myriophyllum spicatum L. is a nonindigenous invasive plant in North America that can displace the closely related native Myriophyllum sibiricum Komarov. We analyzed the chemical composition (including: C, N, P, polyphenols, lignin, nonpolar extractables, and sugars) of M. spicatum and M. sibiricum and determined how the chemistry of the two species varied by plant part with growing environment (lake versus tank), irradiance (full sun versus 50% shading), and season (July through September). M. spicatum had higher concentrations of carbon, polyphenols and lignin (C: 47%; polyphenols: 5.5%; lignin: 18%) than M. sibiricum (C: 42%; polyphenols: 3.7%; lignin: 9%) while M. sibiricum had a higher concentration of ash under all conditions (12% versus 8% for M. spicatum). Apical meristems of both species had the highest concentration of carbon, polyphenols, and tellimagrandin II, followed by leaves and stems. Tellimagrandin II was present in apical meristems of both M. spicatum (24.6 mg g−1 dm) and M. sibiricum (11.1 mg g−1 dm). Variation in irradiance from 490 (shade) to 940 (sun) μmol of photons m−2 s−1 had no effect on C, N, and polyphenol concentrations, suggesting that light levels above 490 μmol of photons m−2 s−1 do not alter chemical composition. The higher concentration of polyphenols and lignin in M. spicatum relative to M. sibiricum may provide advantages that facilitate invasion and displacement of native plants.