Inhibitory effect of aqueous extracts of Centaurea solstitialis subsp. schouwii on seed germination and growth of Sulla coronaria

Botany ◽  
2020 ◽  
Vol 98 (5) ◽  
pp. 273-281
Author(s):  
Chadlia Hachani ◽  
Mohammed S. Lamhamedi ◽  
Mejda Abassi ◽  
Zoubeir Béjaoui

Biodiversity has been confronted with anthropogenic threats and several natural threats such as biological invasions. The success of these invasions involves phytotoxic products released by invasive plants that can exhibit allelopathic effects on target species. Thus, aqueous extracts from different parts of the Mediterranean yellow star-thistle [Centaurea solstitialis subsp. schouwii (DC.) Gugler], were tested for their allelopathic effects on seed germination and seedling growth of Sulla coronaria (L.). Bioassays were conducted in vitro to test the effects of the aqueous extracts of shoot, basal and root parts of C. solstitialis subsp. schouwii at two different concentrations (50 g·L−1 and 10 g·L−1). The concentrations of total polyphenols, flavonoids, and tannins of the extracts were also evaluated. Our results showed inhibitory effects on the germination and seedling growth of S. coronaria seedlings, particularly with the extract form the basal part, reaching 84%. This study confirms the linear relationships between the allelopathic effects of C. solstitialis subsp. schouwii and the polyphenol and flavonoid contents. However, further experiments are needed under field conditions to confirm the results obtained under laboratory conditions.

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.


2014 ◽  
Vol 1073-1076 ◽  
pp. 172-175
Author(s):  
Xun Zhi Zhu ◽  
Hong Bo Han ◽  
Qiang Li

Eupatorium adenophorum (croftonweed), one of the most destructive alien species in China, has been demonstrated or indicated to have inhibitory effects on other species in laboratory bioassay. However, allelopathic compounds of E. adenophorum may play other roles more than interspecific interference. Here we investigated whether E. adenophorum aqueous leachates could influence conspecific seed germination and seedling growth with laboratory bioassay and found that it could inhibit seed germination and reduce seedling root elongation of E. adenophorum. Then we examined interactions between E. adenophorum leachate and natural soil on germination and seedling growth of E. adenophorum itself. The results showed that soil from different habitats altered the allelopathic effects usually observed in laboratory bioassay. In the heavily invaded site, E. adenophorum were inhibited by E. adenophorum leachates; whereas, in two lightly invaded sites, germination and seedling growth of E. adenophorum was significantly facilitated. We can infer that allelochemicals from E. adenophorum play a dramatic role in regulating its population density.


2017 ◽  
Vol 23 (2) ◽  
Author(s):  
G. S. THAKUR

In this study the allelopathic effects of Parthenium hysterophorus on seed germination and seedling growth in Cajanus cajan (Pigeon pea) was investigated. The dried powdered leaves of Parthenium hysterophorus were soaked in distilled water for 24 hours to obtain aqueous extract of leaves and sterilized seeds were treated with 2%, 4%, 6%,8%, and 10% concentration of extract in triplicate. The germinated seeds were counted every day to observe germination index (G.I.) and mean germination time (MGT). It has been found that germination index (GI) were significantly decreased and MGT were delayed to germinate with increasing concentration. It has been observed that seed germination percentage, root length, shoot length and seedling vigor index were reduced at >2% as compared to control. The 10 % aqueous extract showed completely inhibitory effect on seed germination. The present investigation showed that the leaves aqueous extract of Parthenium hysterophorus had inhibiting effects on seed germination and seedling growth in Cajanus cajan (Pigeon pea).


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