Identification and Phytotoxicity Assessment of Phenolic Compounds in Chrysanthemoides monilifera subsp. monilifera (Boneseed)

Abstract

Chrysanthemoides monilifera subsp. monilifera (boneseed), a weed of national significance in Australia, threatens indigenous species and crop production through allelopathy. We aimed to identify phenolic compounds produced by boneseed and to assess their phytotoxicity on native species. Phenolic compounds in water and methanol extracts, and in decomposed litter-mediated soil leachate were identified using HPLC, and phytotoxicity of identified phenolics was assessed (repeatedly) through a standard germination bioassay on native Isotoma axillaris. The impact of boneseed litter on native Xerochrysum bracteatum was evaluated using field soil in a greenhouse. Collectively, we found the highest quantity of phenolic compounds in boneseed litter followed by leaf, root and stem. Quantity varied with extraction media. The rank of phenolics concentration in boneseed was in the order of ferulic acid > phloridzin > catechin > p-coumaric acid and they inhibited germination of I. axillaris with the rank of ferulic acid > catechin > phloridzin > p-coumaric acid. Synergistic effects were more severe compared to individual phenolics. The litter-mediated soil leachate (collected after15 days) exhibited strong phytotoxicity to I. axillaris despite the level of phenolic compounds in the decomposed leachate being decreased significantly compared with their initial level. This suggests the presence of other unidentified allelochemicals that individually or synergistically contributed to the phytotoxicity. Further, the dose response phytotoxic impacts exhibited by the boneseed litter-mediated soil to native X. bracteatum in a more naturalistic greenhouse experiment might ensure the potential allelopathy of other chemical compounds in the boneseed invasion. The reduction of leaf relative water content and chlorophyll level in X. bracteatum suggest possible mechanisms underpinning plant growth inhibition caused by boneseed litter allelopathy. The presence of a substantial quantity of free proline in the target species also suggests that the plant was in a stressed condition due to litter allelopathy. These findings are important for better understanding the invasive potential of boneseed and in devising control strategies.

Assaying the potential autotoxins and microbial community associated with Rehmannia glutinosa replant problems based on its ‘autotoxic circle’

“…Research on canola suggested that the synergistic effect of sinapyl alcohol, p-hydroxybenzoic and 3,5,6,7,8-pentahydroxy flavones played a role for canola allelopathy against annual ryegrass (Asaduzzaman et al 2015). Research on boneseed's allelopathy indicated that the mixture of ferulic acid, catechin, phloridzin and pcoumaric acid showed a stronger inhibiting effect on Isotoma axillaris compared to individual phenolics (Al Harun et al 2015). The combined allelopathic effect of three allelochemicals of Chara vulgaris also expressed Data is the average values with standard errors of the replicates.…”

“…In recent years, increasing compounds (like ketones, alkaloids, terpenes) were reported as potential allelochemicals of other plants (Guo et al 2015;Kato-Noguchi et al 2011;Ma et al 2009). Interestingly, the growth inhibitory activity of some potential allelochemicals was much greater than that of phenolic acids (Kato-Noguchi et al 2012), and some compounds presented a synergistic effect when exhibiting their allelopathic effect (Al Harun et al 2015;Zhang et al 2012;Zuo et al 2015). In previous studies, the polar compounds in ethyl acetate extraction of R. glutinosa leaves and fibrous roots have been preliminary analysed for the identification of allelochemicals (Li et al 2012;Wang et al 2010).…”

Phytotoxicity, cytotoxicity and antioxidant activity of the invasive shrub Austroeupatorium inulifolium (Kunth) R.M. King & H. Rob

“…However, the effect was more pronounced in CH3OH extracts of A. inulifolium, where polar compounds are commonly found. Methanolic extracts of some plant species were known to contain phenolics and other toxic substances (Belicova et al, 2001;Al Harun et al, 2015). These phenolics may inhibit the germination process through their interference in the indole acetic acid metabolism, or synthesis of protein and Some bioactivities of Austroeupatorium inulifolium 97 iron uptake by plants (Blum, 1998;Castro et al, 1984).…”

Protection of Eggplant Seed Germination from the Inhibitory Effect of o-Cresol by Bioaugmentation of Soil with Pseudomonas monteilii Strain

“…Severe inhibition of germination of Isotoma axillaris was described to be due to ferulic acid, catechin, phloridzin, and p-coumaric acid generated by boneseed (Chrysanthemoides monilifera subsp. monilifera) litter [38]. Long-term cultivation of lemon balm was shown to accumulate phenolics in the soil and exert phytotoxic effects on the growth and the essential oil yield [39].…”