The Allelopathic Potential of Rosa blanda Aiton on Selected Wild-Growing Native and Cultivated Plants in Europe

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.

The Role of Flavonoids in Invasion Strategy of Solidago canadensis L.

This study provides data on the problem of potential complexation of phenolic compounds synthesized by the plants Solidago canadensis L. and Solidago gigantea Ait. with ammonium forms of nitrogen, partly immobilized in the soil. A comparative analysis of secondary metabolites of the studied plants was performed by HPLC. The leaves of invasively active Solidago canadensis contain nine times more rutin than the plants of Solidago gigantea. Adding to the leaf extracts (v/v1/20) aqueous ammonia solution to pH 8.0 on the chromatograms decreases the intensity or completely causes peaks of flavonoids to disappear; instead, there are peaks of new polar substances (tR 1.5 and 2.0 min). The selective effect of the phenol-ammonium complex on various plant species was revealed. At a concentration of 20 μg/mL, these substances stimulated the formation of lateral roots in soybean seedlings and chrysanthemum cuttings. The suppression of root growth in radish seedlings occurred at a concentration of flavonoids in the extract of 25 μg/mL. In addition, a positive chemotaxis of the Pseudomonas putida (PGPR) was detected in the nitrogen-containing complex based on rutin (5 μg/mL). The identified feature allows PGPR colonization of the root system of Solidago canadensis with corresponding changes in the structure of the microbial community. The ability of the obtained nitrogen-containing polar complexes to regulate the growth processes of plants at extremely low concentration points to promising research in this direction.

Germination and growth of radish under influence of nipplewort aqueous extracts

The conducted experiment was aimed at determining the effect of aqueous extracts from dry roots and shoots of common weed nipplewort (Lapsana communis L. subsp. communis) on seeds germination and early growth of radish (Raphanus sativus L. var. radicula Pers.), cultivars ‘Rowa’, ‘Krakowianka’, ‘Półdługa’. The experiment was carried out in the form of Petri dishes tests with 3 different percentage concentrations of extracts (1%, 3% and 5%, respectively). The germination indexes used here revealed that the germination capacity of the radish seeds was significantly inhibited by extracts from the roots and shoots of L. communis subsp. communis. The elongation growth of radish roots and hypocotyls was stimulated to a higher percentage by extracts from nipplewort roots than by extracts from shoots. The fresh and dry mass of the radish seedlings depended on the type (roots/shoots) and concentration of the extract as well as the radish cultivar. The electrolyte leakage was the highest in seedlings watered with 5% extract of nipplewort shoots. The cultivar most sensitive to nipplewort extracts turned out to be ‘Półdługa’, and the least sensitive was ‘Rowa’. The response of radish seeds to nipplewort extracts is probably due to the presence of allelochemical compounds and their synergistic interaction.

Effects of rhizome extracts from invasive knotweed species Fallopia japonica and F. ×bohemica on radish seed germination and root growth of seedlings

Japanese knotweed (Fallopia japonica) (Houtt.) Ronse Decr. and Bohemian knotweed (F. ×bohemica) (Chrtek and Chrtková) J. P. Bailey are invasive plants in Slovenia. We studied the effects of aqueous extracts [0.5 %, 1 %, 2 %, 5 % and 10 % (w/v)] from rhizomes of F. japonica and F. ×bohemica on the seeds of radish (Raphanus sativus) and examined the morphological and biochemical changes during germination and early growth of seedlings. Germination and early growth of radish were monitored 3, 5 and 7 days after treatment. Extracts of these two knotweed taxa delayed seed germination and strongly reduced the length of the primary root, but had less effect on shoot growth. These extracts triggered stress-induced morphogenic responses in the treated radish seedlings, stimulating the formation of lateral roots at low concentrations and causing inhibition at high concentrations. The extract concentration and not the knotweed taxon influenced the biochemical markers of oxidative stress in the radish. Total antioxidative capacity was increased in treated radish seedlings. The extract of F. japonica had a greater impact on the radish morphology than that of F. ×bohemica, with similar influences on the biochemical parameters. High pressure liquid chromatography identified emodin, resveratrol, catechin and epicatechin in the rhizomes of both knotweed species. Their contents were species dependent.

Effect of seed halopriming on improving salt tolerance in Raphanus sativus L

In this paper, effect of halopriming on germination, initial growth and development of radish under salt stress conditions was investigated. The seeds were treated with different concentrations salts of calcium, potassium, and sodium chloride (CaCl2, KCl, NaCl, respectively) in the form of a standard germination method and priming method, which involves modification of the metabolic activity of seeds in the pregerminative phase. The obtained results showed that all applied salts had inhibitory effects on germination characteristics (GP, RG and U, except MTG) and development of radish seedlings (shoot and root elongation, weight and vigour). Halopriming contributed to the improvement of tolerance to stress conditions, because the obtained values of all germination and growth characteristics were significantly increased. The best effect being achieved by priming with CaCl2 for germination characteristics and vigour and with KCl for initial development.

Effect of Aqueous Extracts from Solidago Canadensis L. Leaves on Germination and Early Growth Stages of Three Cultivars of Raphanus Sativus L. Var. Radicula Pers

Solidago canadensis L. is an expansive perennial that forms persistent, species-poor plant communities. It often spreads in fallow areas, displacing native floristic ingredients. Its expansiveness is largely due to morphological features, but it can also be the effect of allelopathic interaction. The aim of the experiment was to investigate the effect of aqueous extracts (decoction, infusion, and maceration) from dry S. canadensis leaves on germination and early growth stages of Raphanus sativus L. var. radicula Pers., in three cultivars: ‘Rowa’, ‘Półdługa’, and ‘Krakowianka’. In comparison to the control, the percentage of germinated radish seeds of ‘Rowa’ cultivar was statistically lower on the infusion and macerate. Regardless of the cultivar, the smallest changes in germination were found in seeds watered with decoction, and the largest with macerate. Seedlings length was most inhibited on macerate substrates, and least with infusion. Regardless of the form of the extract, each of them negatively affected the initial growth of radish seedlings. A fresh mass of ‘Rowa’ seedlings was inhibited by all Canadian goldenrod extracts. In relation to the control, the ‘Krakowianka’ cultivar was the least sensitive to S. canadensis extracts. The total chlorophyll content was the lowest in the seedlings of the ‘Rowa’ and ‘Półdługa’ cultivars germinated on macerate, compared to the control and two others extracts. The percentage of electrolyte leakage depended on the type of extract used and the radish cultivar. The study showed that depending on the cultivar, the aqueous extracts from S. canadensis leaves decreasing of germination and early growth of R. sativus.

Allelopathic effect of goosefoot on germination and early stage growth of triticale and radish

The aim of this study was to investigate the effect of aqueous extracts from Chenopodium album L. on germination and early stages of triticale grains (×Triticosecale Wittm. ex A.Camus) and radish seeds (Raphanus sativus L.). Germination indexes, fresh and dry mass, water content and electrolyte leakage were measured. Studies revealed the different germination capacity of triticale grains and radish seeds, where increased concentrations of allelopathins in aqueous C. album extracts significantly inhibited seedling growth for both species. The extracts had an inhibitory effect on the growth of seedling fresh mass. An increase in dry mass of radish seedlings was demonstrated for each of the extracts and, for triticale seedlings, only at concentrations of 0.5% and 1.5%. Water content in triticale and radish seedlings varied depending on the concentration of allelopathins in the extract. With increasing concentrations of C. album extract, regardless of seedling type, a statistically significant increase in electrolyte leakage was observed.