Viktória Lilla Balázs

Can seasonal dynamics of allelochemicals play a role in plant invasions? A case study with Helianthus tuberosus L.

Helianthus tuberosus L. (Jerusalem artichoke), a perennial plant native to North America, is one of the most dangerous invasive species in Europe. The fast spread of the plant may be enhanced by its allelopathic effects, through the release of chemical compounds into the environment. The goal of this work was to determine the allelopathic effect of different plant parts of H. tuberosus and to study the temporal changes of allelopathic factors throughout the vegetation period, based on germination bioassays, chemical analysis of allelochemicals, and greenhouse experiments. Bioassay results demonstrated differences in the effect of H. tuberosus extracts, depending on the concentration, the test species, the plant part used for extraction, and the time of the treatment. From the bioactive compounds salicylic acid, 2-OH-cinnamic acid and 4-OH-benzaldehyde showed characteristic distribution patterns throughout the vegetation period. In the competition experiment, the presence of H. tuberosus exerted a strong negative effect on all tested species, independently of their treatment with activated carbon. Based on our results, we concluded that H. tuberosus can interfere with other species through allelochemical interactions. Moreover, seasonal dynamics of allelochemicals could be more important than suspected in plant competition and is likely to play an important role in the spread of the invasive H. tuberosus into new areas.

Helianthus tuberosus L. agg. in the Carpathian Basin: a blessing or a curse?

Helianthus tuberosus agg., an herbaceous perennial plant from the Asteraceae family, is native to North America and was introduced as a crop to Europe in the seventeenth century. The status of this plant has been rather controversial in the Carpathian Basin. This paper reviews its taxonomy, chorology, and ethnobotany in this region, using data obtained from herbarium specimens, ethnobotanical surveys performed in Transylvania, and data published earlier, documenting the invasive features of the plant since the beginning of the nineteenth century. Our results suggest that (1) Helianthus tuberosus agg. has been present in the Carpathian Basin from the nineteenth century, (2) its taxonomy is problematic since the first part of the nineteenth century; (3) ethnobotanical surveys confirmed that the plant’s tuber has been locally used mostly as a food in Transylvania, collected from cultivation. Overall, Helianthus tuberosus agg. is both a ‘blessing and a curse’ at the same time, it is a valuable crop with beneficial nutritional value, and also an environmentally dangerous invasive element for the diversity of the flora of the Carpathian Basin.

Ethnomedicinal treatment of gastrointestinal disorders in Transylvania, Romania

Ethnomedicine using mostly plants is of pivotal importance nowadays in several Transylvanian regions in Romania. In this study (2007–2015), one Swabian-German, one Hungarian, three Csango-Hungarian and nine Szekely-Hungarian villages were selected to collect ethnomedicinal treatments for various gastrointestinal diseases. Some of the studied villages have partial or no permanent medical and pharmaceutical services. The 374 inhabitants interviewed used mostly medicinal plants based on ancient knowledge. The 78 (53 wild and 25 cultivated) plants documented have 181 local names and are used to treat ailments such as loss of appetite, bloating, stomach ache, gastric ulcer, and diarrhea, mostly in tea form. This knowledge decreases continuously because of loss of interest among young people and through frequent use of media sources and books. Although some of these plants have also been described in official medicinal sources, several data suggest the need for further fieldwork and new experimental analyses to...

Histological and antimicrobial study of Ononis arvensis L.

In this study field restharrow (Ononis arvensis) was investigated for histological and antimicrobial features. The aerial part and the root were embedded in synthetic resin and investigated following sectioning by a rotation microtome. The antimicrobial activity and minimum inhibitory concentration of the solvent fractions of the aerial part were studied against four bacterial strains and one fungus. According to histology, the root covered by rhizodermis contains contiguous vascular elements, which are surrounded by sclerenchyma cells. The epidermis cells are anisodiametric in the stem, sepal, and petal. The bundles of the stem form a Ricinus type thickening. The adaxial side of the heterogeneous leaf is covered by unbranching non-glandular and capitate glandular trichomes. The stipule, petiole, sepals and petals are isolateral having mesomorphic stomata. Pollen grains are tricolpate. The different extracts of the herb showed antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium, Staphylococcus aureus, and Candida albicans. Data show that the extracts of the leaf contain compounds which may be responsible for the antifungal effect, while extracts obtained from display against the tested bacteria, except Escherichia coli. Further studies are required to complete the phytochemical analysis and identify the antimicrobial compounds of extracts.