Allelopathic activity of the scentless false mayweed (Tripleurospermum inodorum (L.) Sch. Bip.)

The purpose of reseach was to study the allelopathic activity of T. inodorum in laboratory conditions against seeds and seedlings of watercress (Lepidium sativum L.). Objectives: to identify the effect of aqueous extracts of different concentrations of the dry aerial part of T. inodorum on the dynamics of germination and the initial growth of test plant seedlings; to compare the allelopathic effects of T. inodorum identified by two biotesting methods. We used classical methods for determining the allelopathic activity of plants by biotesting on seeds and seedlings of higher plants. The preparation of a concentrated (1: 25) aqueous extract was carried out using the hot extraction method (4 g of the above-ground part of the three-rib was poured into 100 ml of boiling water and infused for 1 hour). By successively diluting the initial extract, solutions of lower concentrations were obtained (1: 50, 1:100 and 1: 200). The results obtained indicate a high allelopathic activity of aqueous extracts of the dry aerial part of T. inodorum, which is expressed in a decrease in seed germination and inhibition of seedling growth. With an increase in the concentration of aqueous extracts of three-ribs, the sizes of the root and hypocotyl naturally decrease. Moreover, the most sensitive organ of the test plant is the root, the size of which at the weakest concentration (1:200) decreases by almost 2 times, while the size of the hypocotyl decreases slightly. A more clear concentration dose-effect relationship was shown by the results of biotesting for root elongation. As the concentration of extracts increases, the size of watercress roots gradually decreases, and the toxicity index of aqueous extracts increases from 21.4 to 86.6 %.