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.

Accumulating evidence points to the multidimensional role of ultraviolet radiation in plant growth and development. Ultraviolet-A (UV-A), as the main component of UV radiation in nature, has a wide range of effects on plants. As there is some evidence of its positive effect as a regulator of plant growth in a controlled environment, there has long been interest in the use of UV-A in agriculture. However, the role of UV-A in plant growth remains largely unknown and the number of studies looking at the effects of UV-A in a controlled environment is still too small. The review carried out here also includes the effects of other UV components on plant growth, morphology and physiology, such as: UV-B, as well as the interplay of other abiotic stresses and UV-A as growth regulators. On the basis of the synthesis presented here, it can be concluded e.g. that lower doses of UV-A radiation can stimulate the growth of plant in a controlled environment. Perhaps it will soon contribute to the optimization of indoor plant growing recipes.

In Europe, Rosa gorenkensis Besser is considered an invasive species. However, its negative impact on native flora components or other habitat components has not been described so far. In the experiment, the germination reactions of mono- and dicotyledonous plant seeds to the aqueous extracts of R. gorenkensis were investigated to determine the allelopathic potential of this plant. Seeds of common plants – wild-growing Festuca rubra L. and cultivated Raphanus sativus L. var. radicula Pers. cv. ‘Rowa’ were treated with aqueous extracts from the roots, stalks, leaves, and flowers of rosa at concentrations of 1%, 2.5%, and 5%. Along with the increase in the concentration of allelochemical compounds in the extracts, the negative influence of the extracts on the germination capacity of the tested seeds species was found. Regardless of the type of extract, inhibition of the growth of the underground and aboveground parts of seedlings was also observed. Changes in biomass and water content, depending on the concentration and type of the extract, were found. The greatest differences in the electrolytes leakage in seedlings watered with 5% extracts were revealed. The study showed that the aqueous extracts of leaves and flowers of this species had the greatest allelopathic potential.