Invasive plant species are responsible for changing colonized ecosystems by occupying new areas and creating a threat to the functioning of the native flora and fauna populations. Alien plants can produce allelochemicals, substances completely new to indigenous communities. This study investigated the germination seed reactions of Festuca rubra L. and Raphanus sativus L. var. radicula Pers. cv. Rowa on the extracts from the roots, stalks, leaves, and flowers of Rosa blanda. Aqueous extracts at concentrations of 1%, 2.5%, and 5% were used in order to determine the allelopathic potential of this alien rose for Europe. With the increase in the concentration of extracts, a decrease in the germination capacity of seeds of the tested species was observed. R. blanda extracts inhibited the growth of seedlings. Depending on the concentration and type of the extract, changes in biomass and water content in Red Fescue and Red Radish seedlings were also shown. The highest differences in the electrolyte leakages were noted in seedlings treated with 5% rose extracts. The study showed that the aqueous extracts of R. blanda leaves and flowers had the greatest allelopathic potential.

Phacelia tanacetifolia Benth. is a melliferous, phytosanitary fodder plant. An important factor in understanding the biology of this plant is to investigate its allelopathic potential. In the experiment conducted here, ×Triticosecale Wittm. cv. Mamut was treated with water extracts from the roots, stems, leaves, and flowers of phacelia at concentrations of 10%, 12.5%, 15%, and control with 0% of extract. After 7 days of exposure, the germination of grains was assessed by analysing, seedling growth, mass parameters, water content, and electrolytes leakage. Aqueous extracts from the stalks, leaves, and flowers of phacelia significantly inhibited kernel germination at a 10% concentration, and from roots at a 12.5% concentration. The elongation growth of triticale seedlings was significantly inhibited by each of the extracts. Extracts from the leaves and flowers caused a significant reduction in fresh mass at a 10% concentration and extracts from the stalks at a 12.5% concentration. A significant reduction in water content was also found in seedlings watered with extracts of 10% from roots, stalks, and leaves and 12.5% from flowers. Extracts from phacelia roots at a 12.5% concentration and extracts from stalks, leaves, and flowers at a 10% concentration significantly increased the leakage of electrolytes. In general, phacelia exhibits allelopathic potential at higher concentrations of extracts.

This study attempts to determine which of the habitats occupied by Filipendula vulgaris creates better conditions for its growth and development. Selected physiological parameters—PSII activity, chlorophyll content, electrolyte leakage, hydrogen peroxide content as well as biomass, the occurrence of mycorrhiza, and soil characteristics—were investigated. Grassland soils had a higher content of macronutrients and a lower concentration of heavy metals. The degree of colonization of F. vulgaris by AMF (Arum type) oscillated around high values in both types of stands. Plants growing on xerothermic grasslands achieved much better fluorescence parameters than those collected from meadows. Similar results were obtained from the analysis of chlorophyll content. The destabilization degree of cell membranes was significantly higher in plants collected in meadows than in grasslands. Biomass analysis showed higher values of these parameters in grassland plants. In the case of the parameters of fluorescence emission, plants growing on grasslands achieved significantly lower values than plants collected from meadows. The analyses carried out showed that better conditions for growth and physiological activity of F. vulgaris are probably associated with grasslands on a calcareous substrate.

The study investigated compounds present in the invasive grass Hordeum murinum L. subsp. murinum and tested the allelopathic potential of this plant against common meadow species Festuca rubra L. and Trifolium repens L. Gas chromatography–mass spectrometry (GC–MS) performed separately on the ears and stalks with leaves of wall barley revealed 32 compounds, including secondary metabolites, that may play an important role in allelopathy. Two compounds, N-butylbenzenesulfonamide (NBBS) and diphenylsulfone (DDS), were described for the first time for wall barley and the Poaceae family. The presence of 6,10,14-trimethylpentadecan-2-one (TMP) has also been documented. Aqueous extracts of H. murinum organs (ears and stalks with leaves) at concentrations of 2.5%, 5%, and 7.5% were used to evaluate its allelopathic potential. Compared to the control, all extracts inhibited germination and early growth stages of meadow species. The inhibitory effect was strongest at the highest concentration for both the underground and aboveground parts of the seedlings of the meadow species tested. Comparing the allelopathic effect, Trifolium repens proved to be more sensitive. In light of the results of the study, the removal of wall barley biomass appears to be important for the restoration of habitats where this species occurs due to its allelopathic potential.

Black cherry (Prunus serotina Ehrh.) is a plant species belonging to the Rosaceae Juss. family that was introduced to Europe, including Poland, to supplement forest floor vegetation, as an ornamental and utilitarian plant. It has numerous uses, including culinary, cosmetic, and medicinal applications. However, as an invasive species, black cherry has begun to spread uncontrollably, negatively affecting local biodiversity and threatening native plants. One characteristic of alien species is their allelopathic potential. In the present study, the allelopathic effects of aqueous leaf and branch extracts of American black cherry at different concentrations (2.5%, 5%, 7.5%, and 10%) on the germination and early growth of two species: Festuca arundinacea (monocotyledonous) and Raphanus sativus var. sativus ‘China Rose’ (dicotyledonous) were investigated. This experiment was conducted using Petri dish assays. The results showed that the extracts inhibited the germination and growth of radish and fescue seedlings. P. serotina exhibited stronger allelopathic effects with increasing extract concentrations, hindering seed germination and seedling growth. Leaf extracts showed greater inhibitory effects than branch extracts, compared to the distilled water control. Leaves likely release more allelochemicals, which is important because fallen leaves accumulate during winter and may constitute a significant source of allelopathic substances.

Lyme borreliosis is a bacterial disease transmitted by ticks infected with Borrelia burgdorferi bacteria. It has non-specific symptoms, such as headaches, fever, and muscle or joint pain, which is why it is often confused with other diseases. There are three stages in its course: early (erythema migrans), early disseminated (osteoarticular and central nervous system disorders), and late (musculoskeletal disorders, arrhythmia, unilateral facial palsy, inflammation of the brain, spinal cord, headaches, etc.). Treatment consists of antibiotic therapy. After treatment, patients can use herbal protocols that support the body and can improve well-being. The main purpose of this study was to compile a list of plants used to support Lyme disease therapy after antibiotic therapy, based on herbal preparations and dietary supplements available for sale without a prescription in Poland. 29 preparations available in stationary stores and 48 herbal preparations available via the Internet (a total of 77 over-the-counter drugs and supplements) were analysed. 101 plants and one species of fungus were recorded in the composition of the preparations. Many plants used in this type of supportive phytotherapy do not have a direct effect against Lyme spirochaetes and have an effect that generally supports the proper functioning of the body. Some, however, have proven bactericidal properties (most of them have not been proven to have a direct effect in the fight against Lyme disease), are virucidal, support the proper functioning of the nervous system, and provide many vitamins and minerals needed for health.