Allelopathic potential of Argemone mexicana L. a tropical weed

Abstract

Effect of Argemone mexicana L. on seed germination and early seedling growth of six crop species was investigated. Aqueous extract of A. mexicana inhibited germination, root and shoot growth of all the test species. The species showed differential response. Germination was reduced by the aqueous shoot extract in the order: pearlmillet > mustard > wheat> carrot> corn > turnip. Root length was reduced in the order:corn> pearl-millet> wheat > mustard > turnip> carrot, whereas shoot length was reduced in the order: pearl-millet> wheat> corn > turnip> mustard > carrot. Decaying A. mexicana in sandy loam soil at a rate of 5,10,20 g / 400 g soil substantialy inhibited germination and seedling growth of pearl-millet. Bioassay of the extract of A. mexicana revealed three phenolic inhibitors and paper chromatography revealed the presence of p-hydroxybenzoic, vanillic and salicylic acids.

Allelopathic Effect of Aqueous Extract of Argemone mexicana L on Germination and Growth of Brachiaria dictyoneura L and Clitoria ternatea L

“…Elsewhere, other researchers found that cinnamic acid was an allelochemical responsible for allelopathy for root growth in cucumber [32] and shoot and root length of cabbage seedlings [33]. Hence results on seedling growth found in this study conforms to findings reported by Alagesaboopathi [23]; Paul and Begum [24]; Jilani et al [25]; Burhan and Shaukat [21] who reported allelopathic effect of A. mexicana on the growth of tomato, sorghum, lentil, carrot, wheat, mustard, turnip, pearlmillet, corn, blackgram and rapeseed.…”

“…This might have been caused by some of allelochemicals present in leaf and seed aqueous extracts of A. mexicana. These results correlates with studies conducted by Burhan and Shaukat, [21] Paul and Begum [22] and Alagesaboopathi [23] who reported seed germination inhibition of Sorghum bicolor, carrot, wheat, mustard, turnip, pearl-millet, blackgram, rapeseed wheat and corn with increase in A. mexicana leaf and shoot extracts concentration. The germination reductions in these studies were related to the allelopathic potential of A. Mexican.…”

“…A. mexicana is amongst invasive weeds reported to release allelochemicals which affect some other species within its vicinity especially crops in agricultural fields. Burhan and Shaukat [21] reported the inhibition effect of A. Mexicana extracts in seed germination, root and shoot growth of pearl-millet, mustard, wheat, carrot, corn and turnip caused by allelopathic compounds dissolved in extracts. Another study by Paul and Begum [22] indicated that seed germination percentage, root length, shoot length and seedling dry weight of blackgram (Vigna mungo) and rapeseed (Brassica napus) were significantly decreased with the increase of both root and leaf extracts of A. mexicana.…”

Allelopathic Effects of <i>Argemone mexicana</i> to Growth of Native Plant Species

“…The allelochemical also initiates a series of reactive oxygen species (ROS) in root meristem which inactivate enzymes, damage vital cellular organelles in plants, and destroy membranes by inducing the degradation of pigments, proteins, lipids and nucleic acids which ultimately results in death of the root system [62] [63]. It were also significantly decreased with the increase of both root and leaf extracts concentration of A. mexicana [34] [64]- [66]. Therefore, A. mexicana is known to possess allelochemicals that might induce reduced root and shoot growth in different plant species growing in their vicinity.…”

“…In natural ecosystems, allelochemicals produced by invasive plants can inhibit the growth of competing native species through direct or indirect means, thereby providing the invader with a competitive advantage [3] [32] [33]. Phenolic compounds including p-hydroxybenzoic acid, vanillic acid and salicylic acid (Figure 1) are the major allelochemicals of A. mexicana [34]. Phenolic compounds are amongst the most widespread plant secondary metabolites which are of great significance in plant metabolism like defence against ultraviolet radiation or aggression by pathogens [21].…”