Allelopathic potential of invasive wetland plant Veronica peregrina.
The phytotoxic potential of Veronica peregrina L. was assessed by determining its influence on the germination and growth of the test plant Sinapis alba L. and identification of the allelochemicals present in its tissues. The impact of water extracts of V. peregrina (the gradient of concentrations: 0.5%, 1%, 2% and 4%) on S. alba seed germination and growth (radicle and hypocotyl elongation) was studied in bioassay conducted on Petri dishes with 3-ply layer of filter paper. UHPLC/UV/MS (Ultra-high performance liquid chromatography with diode array detection coupled to electrospray time-of-flight mass spectrometry) was used to separate and identify the allelochemicals present in V. peregrina tissues. The material for the study (whole plants of V. peregrina) was sampled from two fishponds located in Lower Silesia in May of 2018. The results showed that V. peregrina inhibited the germination of seeds. The effect on shoots and roots growth was positive or negative depending on the concentration of extract-low concentrations stimulated while the high ones inhibited growth of seedlings. Three compounds probably responsible for allelopathic activity (protocatechuic acid, luteolin-7-O-glucuronide, verproside) were identified. Presented phytotoxic potential of the species may account for its competitiveness, thus explaining its invasive behavior.