Phytotoxic Effects of Selected Herbal Extracts on the Germination, Growth and Metabolism of Mustard and Oilseed Rape

Abstract

The use of plants that have high allelopathic potential as natural herbicides in the form of aqueous extracts is gaining popularity in environmentally friendly agriculture. Usually, their effect on the germination and growth of weeds is investigated. However, less attention is paid to the effect of the allelopathic compounds from extracts on cultivated plants. Therefore, the aim of this study was to evaluate the impact of herbal extracts that have allelopathic properties on selected physiological and biochemical processes of two plants of great economic importance—white mustard (Sinapis alba L.) and oilseed rape (Brassica napus L. var. oleifera). The extracts were prepared from mountain arnica (Arnica montana L.), ribwort (Plantago lanceolata L.), hypericum (Hypericum perforatum L.), common milfoil (Achillea millefolium L.), sunflower (Helianthus annuus L.) and sage (Salvia officinalis L.). The germination of white mustard and oilseed rape was most inhibited by the extracts that were prepared from sage and sunflower. Additionally, in the germinating plants, the sunflower extracts increased the membrane permeability, which indicates membrane injuries. The metabolic changes in the plants were monitored using isothermal calorimetry and FT-Raman spectroscopy. The total heat production, which provided information about the metabolic activity of the white mustard and oilseed rape, was decreased the most by the sage extract but generally all of the tested extracts disturbed the shape of the heat emission curves compared to the water control. The impact of the allelopathic compounds that are present in the herbal extracts on the metabolism of the seedlings was clearly visible on the FT-Raman spectra—in the fatty acids and flavonoids range, confirmed using a cluster analysis. In conclusion, the herbal extracts from medicinal plants that have herbicidal activity could be used as a natural herbicide for weed control, but since they may also have negative impacts on cultivated plants, preliminary tests are advisable to find the extract from the species that has the least negative effect on a protected crop.

Bio-Herbicidal Potential of Nanoemulsions with Peppermint Oil on Barnyard Grass and Maize

“…The lowest values were recorded for the 5% concentration of the peppermint oil (PN4) treatment, indicating that the higher the peppermint oil concentration in the emulsion, the more inhibitory effects on seed germination and seedling growth. To the best of our knowledge, our results are the first to show the changes in heat emission in the maize and barnyard grass seedlings treated with the PNs but are consistent with those of [ 43 , 44 , 47 ], who found that bioactive compounds from allelopathic plants quantitatively and qualitatively change the heat emission patterns of the acceptor seedlings.…”

“…The obtained spectra showed that the peppermint oil in each of the PNs concentrations accelerated the breakdown of polysaccharides into monosaccharides in the initial seed germination stage as their increase was observed. This may point to the decomposition of storage materials, which is concurrent with the effects observed in other works, e.g., of essential hemp oil on wild oat and cornflower seedlings [ 54 ], and herbal extracts from arnica, ribwort, hypericum, milfoil, sunflower, and sage on seedlings of mustard and oilseed rape [ 47 ]. Additionally, a hierarchical analysis of similarity proved significant differences in the chemical composition of seedlings treated with nanoemulsions with peppermint oil (first group) versus control and surfactants treated plants (second group).…”

“…Metabolic activity during the growth of maize (cv. Lokata) and barnyardgrass ( Echinochloa crus-galli ) seedlings was measured at 20 °C using an isothermal calorimeter TAM III equipped with TAM Assistant Software (Thermo Activity Monitor, TA Instruments, New Castle, DE, USA) according to [ 47 ]. Briefly, three two-day-old seedlings of maize pre-germinated on the distilled water were placed into a 25 mL calorimetric ampoule with 400 μL of PN (concentration: 1%; 1,5%; 2% or 5%) or distilled water (control) at the bottom.…”

Using of Essential Oils and Plant Extracts against Pseudomonas savastanoi pv. glycinea and Curtobacterium flaccumfaciens pv. flaccumfaciens on Soybean

“…Considering that a large number of diverse methods used to determine the phytotoxic effects of EOs and PEs concerning plants [ 61 , 62 ] rather complicate the overall picture, it was decided to determine the phytotoxic concentrations for each of the substances planned for use in vivo in relation to soybean. Moreover, there are precedents for the use of EOs as contact herbicides for weed control, in which a decrease in crop yield was observed [ 63 , 64 ]. In the current study, all tested substances were phytotoxic to soybean seeds and leaves at certain concentrations.…”

The Spectral Compositions of Light Changes Physiological Response of Chinese Cabbage to Elevated Ozone Concentration

“…A complementary method that allows determining the effect of O 3 on photosynthesis is gas exchange analysis, i.e., net photosynthesis, as well as transpiration, stomatal conductance and intracellular CO 2 concentration [6,13,24]. In turn, FT-Raman spectroscopy and light reflectance analysis allow to assess the chemical compositions of plants-in particular, the estimation of the total protective pigments content (such as anthocyanins, flavonols and carotenoids) without affecting the tissue structure [27][28][29][30][31].…”