Allelopathic effects of Sonchus oleraceus L. on the germination and seedling growth of crop and weed species

Abstract

We assessed the allelopathic effects of the aqueous extract of Sonchus oleraceus dry shoots on the germination and seedling growth of Trifolium alexandrinum, three weed species (Brassica nigra, Chenopodium murale and Melilotus indicus) and S. oleraceus itself. We assayed four different concentrations of the aqueous extract (w v −1 ): 1%, 2%, 3% and 4%. To determine whether the effects of the extract were attributable to the presence of allelopathic compounds, its osmotic potential or both, we prepared concentrations of polyethylene glycol (PEG) with osmotic potentials equivalent to those of the aqueous extract. All concentrations of the plant extract completely inhibited the germination and seedling growth of C. murale. The lowest concentration of the plant extract partially inhibited germination and seedling growth of B. nigra, M. indicus and S. oleraceus, whereas the higher concentrations inhibited those parameters completely. The germination of T. alexandrinum was not affected by the aqueous extract at 1% or 2%. In general, the aqueous extracts were more effective in inhibiting seed germination and seedling growth than were the PEG solutions. Phytochemical analyses revealed that phenols and alkaloids were the most abundant compounds in S. oleraceus dry matter. Our results suggest that the aqueous extract of S. oleraceus has an allelopathic effect on some weeds, and its usefulness as a bioherbicide therefore merits further study.

Flavonoid profiling and nodulation of some legumes in response to the allelopathic stress of Sonchus oleraceus L.

“…In general, this study has confirmed that both plant residue and root exudates of S. oleraceus had a common inhibitory effect on the flavonoid concentrations in the target legumes. This influence could be attributed to the phenolics such as ferulic-, caffeic-, syringic-and p-hydroxybenzoic acids, which were previously detected in plant residue and root exudates of S. oleraceus (Gomaa et al 2014;Hassan et al 2014a;b). Moreover, the plant tissues of S. oleraceus were also reported to contain considerable contents of alkaloids, tannins and saponins (Gomaa et al 2014).…”

“…This influence could be attributed to the phenolics such as ferulic-, caffeic-, syringic-and p-hydroxybenzoic acids, which were previously detected in plant residue and root exudates of S. oleraceus (Gomaa et al 2014;Hassan et al 2014a;b). Moreover, the plant tissues of S. oleraceus were also reported to contain considerable contents of alkaloids, tannins and saponins (Gomaa et al 2014). These were suggested as possible allelopathic candidates which interact with several enzymes causing deviations from the standard biosynthetic pathways of secondary metabolites (Einhellig 2004).…”

“…This species was reported to be strongly allelopathic, reducing germination and growth of other crop and weed species due to liberation of several phenolic compounds either from its decaying dry matter and/ or from its root exudates (Gomaa et al 2014;Hassan et al 2014a;b). Additionally, during weeding practices in cultivated fields, Egyptian farmers typically uproot this plant and mix it with the soil during ploughing.…”

Allelopathic suppression by Conyza canadensis depends on the interaction between latitude and the degree of the plant’s invasion

“…These chemical compounds, known as allelochemicals, are secondary metabolites produced naturally by plant species (Ma et al 2012;Gomaa et al 2014). Previous studies have revealed that the allelopathic effects of invasive plant species, including C. canadensis (Djurdjević et al 2011;, on co-occurring species are mainly due to secondary metabolites (Svensson et al 2013;Macel et al 2014).…”

GGR (Geranylgeranyl Reductase) Expression Affects the Allelopathic Response to Arabidopsis Allelochemicals

“…Furthermore, the use of allelochemicals extracts from several plant species has been investigated for weed control. For instance, extracts from Eugenia dysenterica (Pina, Borghetti, Silveira, & Pereira, 2009), Sonchus oleraceus (Gomaa et al, 2014), and Sorghum bicolor (Amali, Jayasurya, & Ignacimuthu, 2014) have been shown to inhibit the germination and growth of plants. Moreover, molecular studies of genes associated with allelochemical compounds will help to understand the molecular mechanisms involved in allelopathic responses, which can support bioengineering programs to enhance the effectiveness of allelochemicals.…”