ORIGINAL RESEARCH PAPEREffect of aqueous extracts of selected medicinal plants on germination of windgrass [Apera spica-venti (L.) AbstractThe study aimed to determine the effect of aqueous extracts of medicinal plants (Matricaria chamomilla, Hypericum perforatum, Achillea millefolium, and Urtica dioica) containing allelopathic compounds on seed germination in lambsquarters (Chenopodium album) and herbicide-resistant windgrass (Apera spica-venti). A Petri-dish experiment was carried out, in which the effects of five concentrations of aqueous extracts on the germination of weeds were assessed for 10 consecutive days. It was found that the dynamics of seed germination are closely related to the type and concentration of aqueous extract of medicinal plants. The 8% U. dioica aqueous extract posed the strongest inhibitory effect, limiting the germination of both lambsquarters and windgrass. Additionally, weed germination was delayed by 12-72 h in the presence of extracts, compared with the control. Summing up, the aqueous extracts of medicinal plants, especially their higher concentrations, pose a desirable inhibiting effect against the germination of lambsquarters and herbicideresistant windgrass seeds.

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The influence of additives to the peat substrate on the yielding and chemical composition of sweet pepper fruits (Capsicum annuum L.) grown in greenhouseWpływ dodatków do substratu torfowego na plon i skład chemiczny owoców papryki (Capsicum annuum L.) uprawianej w szklarniSummary. The aim of this work was to determine the effect of using various additives to the substrate on the yield and quality of sweet pepper fruits grown in greenhouse. In the experiment four objects were used: 1) peat substrate (control object), 2) peat substrate with coconut fiber, 3) peat substrate with an addition of expanded keramzite, and 4) peat substrate with an addition of perlite. The experiment showed no significant effect of additives on the early, marketable and total yield of fruits and on the content of chlorophyll b. Beneficial effects of coconut fiber added to the substrate were found on the fruit quality: dry matter content, soluble sugar and L-ascorbic acid. The additive of perlite to the substrate had a significant effect on chlorophyll a and chlorophyll a : b ratio. Significant differences in the content of the analysed macroelements: Ca, K, Mg and P in fruits were found depending on the type of substrate used.