scholarly journals Allelopathic and competitive interactions between native and alien plants

Author(s):  
Ling Yuan ◽  
Jun-Min Li ◽  
Fei-Hai Yu ◽  
Ayub M. O. Oduor ◽  
Mark van Kleunen

AbstractThe novel-weapons and homeland-security hypotheses are based on the idea that aliens and natives are not adapted to each other’s allelochemicals as they did not co-evolve. However, as only a few studies have tested this, it remains unclear how important co-evolutionary history is in determining the strength of allelopathic interactions between aliens and natives. Here, we tested for potential pairwise allelopathic effects on each other of five alien and five native herbaceous species in China. We did a germination experiment and a competition experiment. In the germination experiment, we tested whether aqueous extracts of the ten study species had allelopathic effects on each other’s seed germination. In the competition experiment, we tested whether the alien and native species differed in their competitive effects and responses, and whether these were changed by the presence of activated carbon—a presumed allelopathy neutralizer– in the soil. Plant extracts had negative allelopathic effects on seed germination. This was particularly the case for extracts from the native species. Moreover, aqueous extracts had slightly stronger negative effects on germination of the aliens than on germination of the natives. In the competition experiment, on the other hand, the natives suffered more from competition than the alien species did, but we could not relate this to allelopathy. Alien plants had negative competitive and allelopathic effects on native plants, but the reverse was also true. These alien-native interactions, however, were not consistently stronger or weaker than native-native or alien-alien interactions.

2021 ◽  
Author(s):  
Ling Yuan ◽  
Junmin Li ◽  
Feihai Yu ◽  
Ayub Oduor ◽  
Mark van Kleunen

Abstract The novel-weapons and homeland-security hypotheses are based on the idea that aliens and natives are not adapted to each other’s allelochemicals as they did not co-evolve. However, as only a few studies have tested this, it remains unclear how important co-evolutionary history is in determining the strength of allelopathic interactions between aliens and natives. Here, we tested for potential pairwise allelopathic effects on each other of five alien and five native herbaceous species in China. We did a germination and a competition experiment. In the germination experiment, we tested whether aqueous extracts of the ten study species had allelopathic effects on each other’s seed germination. In the competition experiment, we tested whether the alien and native species differed in their competitive effects and responses, and whether these were changed by the presence of activated carbon –a presumed allelopathy neutralizer– in the soil. Plant extracts had negative allelopathic effects on seed germination. This was particularly the case for extracts from the native species. Moreover, aqueous extracts had slightly stronger negative effects on germination of the aliens than on germination of the natives. In the competition experiment, on the other hand, the natives suffered more from competition than the alien species did, but we could not relate this to allelopathy. Alien plants had negative competitive and allelopatic effects on native plants, and the reverse was also true. These alien-native interactions, however, were not consistently stronger or weaker than native-native interactions or alien-alien interactions.


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.


2013 ◽  
Vol 23 (2) ◽  
pp. 157-162 ◽  
Author(s):  
Wibke Wille ◽  
Jan Thiele ◽  
Emer A. Walker ◽  
Johannes Kollmann

AbstractInvasive alien plants often occur in monospecific stands with high density in the invaded range. Production of bioactive secondary metabolites in such stands could have allelopathic effects on germination of native species. We tested this component of the novel weapon hypothesis for Heracleum mantegazzianum, a prominent invader in Europe, using seeds of 11 native herbs exposed to soil or soil extracts from invaded stands, moist seeds or seed extracts of H. mantegazzianum. There was no effect of the various treatments on germination of most species, while germination was reduced in Urtica dioica on invaded soil, in Poa trivialis with H. mantegazzianum seed extract, and negative effects of the essential oil bergapten were found in three species. In P. trivialis the results of the seed extract were not supported by the experiment with added seeds of the invasive plant. Thus, there is limited evidence for allelopathic effects of the invasive H. mantegazzianum on germination of co-occurring native herbs.


2018 ◽  
Vol 66 (4) ◽  
pp. 331 ◽  
Author(s):  
Congyan Wang ◽  
Kun Jiang ◽  
Bingde Wu ◽  
Jiawei Zhou

Increasing levels of heavy metals are released into ecosystems. The influence of heavy metal pollution on successful invasive species has raised considerable interest, particularly regarding potential allelopathic effects on seed germination and seedling development of native species. Adding heavy metals may alter or even enhance such allelopathic effects of invasive species. The aim of the present study was to address the combined treatments of the invasive species Canada goldenrod (Solidago canadensis L.) leaf extracts and cadmium (Cd) pollution on seed germination and seedling development of the homologous native species lettuce (Lactuca sativa L.). Results showed that the combined treatments of Canada goldenrod leaf extracts and Cd pollution significantly decreased seed germination and seedling development of lettuce compared with the control. In addition, the indices of allelopathic effects for all seed germination and seedling development indices of lettuce were less than zero under the combined treatments of high concentration of Canada goldenrod leaf extracts and Cd pollution (regardless of concentration). Thus, the combined treatments of high concentration of Canada goldenrod leaf extracts and Cd pollution pose an inhibitory effect on seed germination and seedling development of lettuce. Further, the combined treatments of high concentration of Canada goldenrod leaf extracts and Cd pollution (regardless of concentration) cause more toxic effects than the combined treatments of low concentration of Canada goldenrod leaf extracts and Cd pollution (regardless of concentration) on all seed germination and seedling development indices of lettuce. Thus, the inhibitory effects of Canada goldenrod on the seed germination and seedling development of co-occurring native species may be intensified at heavy invasion degrees under increased heavy metal pollution. Subsequently, the competitiveness and fitness of native species may be notably decreased via the reduced seed germination and seedling development and then the notorious invader can establish progressively-growing populations in the colonised ecosystems.


2008 ◽  
Vol 22 (4) ◽  
pp. 1095-1100 ◽  
Author(s):  
Denis Coelho de Oliveira ◽  
Geraldo Luiz Gonçalves Soares ◽  
Rosy Mary dos Santos Isaias

Galls induced by Euphalerus ostreoides (Hemiptera: Psyllidae) cause structural and chemical alterations on Lonchocarpus muehlbergianus leaflets. Healthy and galled leaflet tissues of this plant species are rich in secondary metabolites with potential allelopathic effects. This research compares the allelopathic effects of the aqueous extracts of L. muehlbergianus leaflets and galls on seeds and seedlings of Lactuta sativa, and evaluates the chemical impact produced by a gall-inducing insect on the other trophic levels associated with it. The extracts were obtained through static maceration in distilled water (5% p/v). The treatments consisted of aqueous crude extracts and those previously filtered in polyvinylpirrolidone (PVP). After seven days, seedling height was measured, and the radicles were fixed in FAA50 for anatomical analyses. Healthy leaflet and gall aqueous extracts, and those filtered in PVP, significantly inhibited seed germination, with no significant differences between the two groups. Treatments with aqueous extracts reduced seed germination speed and vegetative axis length. Plant tissue alterations confirm the phytotoxicity of allelochemical substances present in the extracts. The differences among the treatments indicated that gall formation altered L. muehlbergianus leaflet metabolism, and this could influence the other trophic levels associated with this gall inducing-host plant system.


2018 ◽  
Vol 12 (2) ◽  
pp. 134 ◽  
Author(s):  
Silvana Fraga Silva ◽  
Halina Stéffany Lopes Costa ◽  
Jesimiel Silva Viana ◽  
Ana Maria Oliveira Ferreira ◽  
Diego Sousa Pereira ◽  
...  

The introduction of species is one of the major causes of biodiversity loss. Invasive exotic plants adapt, propagate and dominate, damaging both natural processes and native species. Thus, the objective was to evaluate the allelopathic effect of three exotic species in the caatinga, on the physiological quality of native forest seeds. Aqueous extracts of leaves of Azadirachta indica, Prosopis juliflora and Cryptostegia madagascariensis were tested to evaluate their effect on the seed germination and seedling vigor of Piptadenia moniliformis, Mimosa tenuiflora and Mimosa caesalpiniaefolia. Seed germination of M. tenuiflora was inhibited by the aqueous extracts of P. juliflora and A. indica in 100% and 42%, respectively, with a reduced GVI with the extracts of P. juliflora and C. madagascariensis. Regarding AEI, P. juliflora extract had positive effect on P. moniliformis seeds and negative on M. tenuiflora seeds, close to -1. A reduction in height of P. moniliformis was observed when the seedlings were in contact with the extracts of the invasive plants studied. For M. tenuiflora, the extract of P. juliflora prevented the formation of seedlings, and M. caesalpiniaefolia presented higher inhibitory effect with extracts of P. juliflora and A. indica. Therefore, M. tenuiflora showed to be sensitive to P. juliflora phytotoxicity.


1992 ◽  
Vol 22 (9) ◽  
pp. 1310-1319 ◽  
Author(s):  
Olle Zackrisson ◽  
Marie-Charlotte Nilsson

Indoor and outdoor experiments demonstrated that allelopathy is an important factor explaining seed regeneration failures of Scots pine (Pinussilvestris L.) in forest floor vegetation dominated by the dwarf shrub Empetrumhermaphroditum Hagerup. Scanning electron micrograph views of the leaf surfaces of E. hermaphroditum reveal secretory glands that are shown to be involved in the release of water-soluble phytotoxic substances. Bioassays indicate that low doses and short exposure times of seeds to leachates have strong negative effects on germination and early root development. Activated carbon can eliminate the inhibitory effects of leachates and litter. This technique demonstrates the occurrence of allelopathic interference by E. hermaphroditum on seed germination of both Scots pine and aspen (Populustremula L.). In a field experiment the allelopathic effects by E. hermaphroditum are strong during early spring when germination and growth initiate and ground ice still is present. Extracts passed through soils collected from an E. hermaphroditum site were detoxified, while those passed through sterilized soil were not. Therefore, microorganisms may detoxify the allelochemicals under some environmental conditions.


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