scholarly journals Preliminary Investigations of Allelopathic Effects and Herbicide-based Eradication of Mesquite (Prosopis juliflora)

Author(s):  
Salim Al-Abdali ◽  
Azan Al-Dhuhli ◽  
Hassan Al-Reasi

Velvet mesquite, locally known as al-ghaf bahri (Prosopis juliflora), is a well-known invasive alien plant species in several regions around the world, including Oman, with various environmental effects. The allelopathic effect of P. juliflora leaves and seed pods on native ghaf (P. cineraria) and a crop species, mung bean (Vigna radiata) was demonstrated. Results indicated that P. juliflora extracts have inhibitory effects on seed germination and seedling growth of both species, particularly on P. cineraria when exposed to pod extracts. For eradication experiments, three herbicides (tribenuron methyl, clethodim and 2,4-D & MCPA) were investigated to determine their inhibitory properties on seed germination, and on the growth and development of young seedlings of P. juliflora. Generally, germination time (GT50, time required for 50% of seeds to germinate) and germination percentage (%) indicated that only 2,4-D & MCPA treatment showed a significant effect on inhibiting seed germination and stopping seedling growth relative to the other two herbicides. The effect of 2,4-D & MCPA was supported by significant reduction in above-ground fresh biomass. The data clearly illustrate the potential negative effects of P. juliflora on other plant species and its tolerance of herbicide treatment. On a farm scale, limited application of 2,4-D & MCPA on young P. juliflora seedlings would be recommended as an effective way to limit further spread and distribution and consequently  to successfully eliminate this invasive alien plant.

2018 ◽  
Vol 111 (2) ◽  
pp. 293
Author(s):  
Seyed Nader MOUSAVIAN ◽  
Hamdollah ESKANDARI

<p>A laboratory factorial (2 × 5) experiment was carried out based on completely randomized block in four replications to evaluate the effect of plant species and concentration of their allelopathic extracts on seed germination and seedling growth of purslane weed (<em>Portulaca oleraceae</em> L.). The first factor studied was plant species (<em>Artemisia sieberi </em>and <em>Salvia syriaca</em>) and the second one the concentration percentage of plant ethanol extract (0.0, 5 %, 10 %, 15 % and 20 %). The effect of <em>Artemisia </em>on<em> </em>germination reduction of purslane<em> </em>was stronger compared to <em>Salvia.</em> The results indicated that higher extract concentration led to decreased germination percentage, germination speed and seedling growth indices of purslane including leaf length, leaf number, leaf width, leaf dry mass, stem mass and stem length. The effect of <em>Artemisia </em>was higher than that of <em>Salvia</em>. In a complementary experiment, the effect plant residues of <em>Artemisia </em>and <em>Salvia </em>(0.0, 1, 2, 3 and 4 g kg<sup>-1</sup> soil) were evaluated in a factorial experiment base on completely randomized block design with three replications. The results of field experiment showed that plant residues significantly (P ≤ 0.01) reduced capsule number per plant, seed number per capsule, seed production and shoot dry mass, while its effect on 1000-seed mass was not substantial. The effect of plant species and the interaction of plant species and their allelopathic extracts concentration had no major impact on the above-mentioned properties. The increase in plant residues in soil, led to the reduction of growth and seed production of purslane induced by plant number per unit area and capsule per plant. <em>Artemisia sieberi </em>Bess<em>. </em>and<em> Salvia syriaca </em>L.<em> </em>residues can be successfully used for non-chemical control of purslane weed.</p>


CORD ◽  
2020 ◽  
Vol 36 ◽  
pp. 41-46
Author(s):  
S.H.S. Senarathne ◽  
S. S. Udumann

Vernonia zeylanica (L.) belongs to the family Asteraceae, is one of the major endemic weed species present in coconut (Cocos nucifera L.) plantations of the tropics, which propagates very easily.  There is a possibility that this plant could also possess allelopathic effects, but this has not been scientifically tested.  Thus, a study was carried out to determine the seed germination of V. zeylanica under soil moisture stress conditions, shoot propagation methods and possible allopathic effects of this species, on selected species in bioassay tests.  Germination of V. zeylanica seeds was not observed at higher osmotic potential (-0.9 MPa).  The highest sprouting percentage of this species were obtained with soft wood cuttings.  The aqueous leaf extract was highly phytotoxic, and it significantly reduced germination and seedling growth of all bioassay species tested. Full strength (33.3 g L-1) aqueous extracts of leaves significantly reduced the germination percentage, root and hypocotyl growth rates of all species tested.  The inhibitory effects were often dependent on concentration.  However, the degree of inhibition varied among the test plant species.  The seedling emergences of all four tested plants were severally inhibited when planted in V. zeylanica contaminated soil.  The results indicated that incorporated aqueous leaf extract of V. zeylanica and its rhizosphere contaminated soil can suppress seed germination, seedling growth and seedling emergence of certain plant species indicating a possible allelopathic effect.


2020 ◽  
Vol 5 (1) ◽  
pp. 01-04
Author(s):  
Mahfuza Begum ◽  
Md. Abdus Salam ◽  
Farhana Zaman

Allelopathy is important for agricultural practices as has gained attention in sustainable agriculture management. Therefore, an experiment was conducted to assess the allelopathic effect of siam weed (Chromolaena odorata L. King and Robinson) debris on the germination and seedling growth of rice, mustard and groundnut at four concentrations of weed debris (e.g., 0, 0.25, 0.5 and 1.0 g dry weight per 100 g soil). The weed debris at different concentrations reduced the seed germination, plant height, leaf numbers, leaf area and seedling dry weight of the test crop species. The inhibitory effects of the test crop were positively related to the concentration of siam weed debris in soil. On the basis of average percent inhibition (API), mustard (24.47%) was mostly affected by the siam weed debris followed by groundnut (20.10%) and rice (17.10%). From the results of the study, it is observed that weed debris of siam weed had inhibitory effect on the seed germination and seedling growth of rice, mustard and groundnut. Therefore, the allelopathic activity of the siam weed may play an important role in the management of sustainable agriculture.


2011 ◽  
Vol 356-360 ◽  
pp. 2767-2773 ◽  
Author(s):  
Yu Hong Wu ◽  
Xu Cheng ◽  
Qing Nian Cai ◽  
Chao Wen Lin

In laboratory bioassay, conducted to study the allelopathic influence of aqueous extracts (0, 2.5, 5.0, 7.5, 10.0% concentration) of twelve hedgerow plant species (Amorpha fruticosa L., Citrus reticulate Banco., Coronilla varia L., Eriobotrya japonica Thunb., Eulaliopsis binata Retz., Gynura bicolor DC., Hemerocallis citrine Baroni., Medicago sativa L., Morus alba L., Toona sinensis Roem., Vetiveria zizanioides L., Zanthoxylum schinifolium Sieb.) which planted in the purple hilly area of Sichuan basin in China was on the germination and seedling growth of wheat (Triticum astivum L.). At 10.0% concentration, The aqueous extracts of twelve hedgerow plant species significantly inhibited the seed germination and seedling growth of wheat except that A. fruticosa, E. binata and V. zizanioides extracts had no effect or slight inhibition on germination of wheat, but the degree of inhibition was species dependent. The allelopathic effect of aqueous extracts from hedgerow plants on wheat was maximum with G. bicolor, H. citrine, C. varia and M. sativa in terms of germination, and G. bicolor , M. sativa, M. alba and H. citrine in terms of shoot length, root length and dry weight, respecitively. The degree of inhibition increased with increase in concentration. Duplication of this work under field conditions is needed, for which the results of this study will form a valuable base.


2021 ◽  
Vol 129 ◽  
pp. 107919
Author(s):  
Wenqin Tu ◽  
Qinli Xiong ◽  
Xiaoping Qiu ◽  
Yongmei Zhang

Author(s):  
Weihong Sun ◽  
Guofeng Yang ◽  
Lili Cong ◽  
Juan Sun ◽  
Lichao Ma

Background: Plant allelopathy refers to the release of chemicals from plants or microorganisms into the environment, may have direct or indirect, beneficial or harmful effects on other plants or microorganisms. When plants grow in an unfavorable environment,more allelochemicals will be secreted and the expression of allelopathic effects will increase, giving plants a certain competitive advantage. Hairy vetch is one of the most promising allelopathic crops and the aqueous extract of hairy vetch has an inhibitory effect on the root length and seedling height of grass crops. The current study aimed to study the allelopathic effect of hairy vetch on alfalfa, and exploring an ecological method to remove the root system of alfalfa.Methods: In this experiment, the allelopathic effects of the seeds, stems and leaves, roots extracts and root exudates (0, 3, 6, 9 and 12 mg·mL-1) on the seed germination and seedling growth of alfalfa were evaluated. And the main allelopathic substances from the stem and leaf extract were isolated and identified using high performance liquid chromatography- mass spectrometry (HPLC-MS).Result: The results showed that all of the extracts can inhibit alfalfa seed germination and seedling growth and stem and leaf extract had the strongest inhibitory effect, especially for inhibiting the root growth. A main allelochemical substance, o-coumaric acid, was screened out and the root length of alfalfa was completely inhibited at 1.6 mg·mL-1 of o-coumaric acid. The findings of these experiments show hairy vetch has strong allelopathic effect on alfalfa and o-coumaric acid is a chemical growth inhibitor.


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