Evaluation of Helichrysum arenarium flower exudate as an inhibitor on Lolium perrene seed germination under laboratory conditions

Compounds accumulated on the surface of plant tissues and structures like glandular trichomes and thin epicuticular layer are defined as exudate, external, superficial. They exhibited important protective activities - antifungal, antibacterial, insect antifeedant, larvicidal, antiplasmodial, and UV protective. The exudate obtained from Helichrysum arenarium flowers was evaluated for its inhibitory activity on germination and initial radicle elongation of Lollium perrene seeds. The experiment was done in vitro in Petri dishes. The exudate, in water–acetone mixture (99.5:0.5), was assayed at concentrations of 1, 3, 5, 7, and 10 mg/mL. The chemical composition of the exudate was analyzed by GC/MS. Exudate solution with 5 mg/mL concentration was found to cause more than 90% of seed germination inhibition. At the same concentration, complete inhibition of root growth was observed. The main bioactive component of exudate was identified as flavonoid aglycone–naringenin. The inhibitory activity of H. arenarium on seed germination was investigated for the first time in the present study.