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•An overview of allelopathy was provided from the history to the applicable modes.•Allelopathic plants and their derived allelochemicals were summarized.•Antialgal capacities of ...allelochemicals were compared.•Mechanisms of allelopathic effects on microalgal cells were elaborated.•Species-selective properties of allelochemicals were presented.
Harmful algal blooms (HABs) have several negative impacts on aquatic ecosystem, and even harm to humans. Utilization of allelochemicals to inhibit microalgal overgrowth is an environment-friendly approach for controlling HABs. This paper demonstrated the development of allelochemicals with algicidal effects, including the development history of allelopathy, the application methods, the reported allelopathic plants and their derived allelochemicals. Allelopathy is a promising strategy to control HABs as the effectiveness of allelochemicals on inhibiting microalgae cells has been discovered and confirmed for many years. The proposed allelopathic mechanisms and species-selective properties were expounded as well. Moreover, this paper further proposed suggestions for the further research and development of allelopathy strategy for HABs control.
Biodiversity is adversely affected by the growing levels of synthetic chemicals released into the environment due to agricultural activities. This has been the driving force for embracing sustainable ...agriculture. Plant secondary metabolites offer promising alternatives for protecting plants against microbes, feeding herbivores, and weeds. Terpenes are the largest among PSMs and have been extensively studied for their potential as antimicrobial, insecticidal, and weed control agents. They also attract natural enemies of pests and beneficial insects, such as pollinators and dispersers. However, most of these research findings are shelved and fail to pass beyond the laboratory and greenhouse stages. This review provides an overview of terpenes, types, biosynthesis, and their roles in protecting plants against microbial pathogens, insect pests, and weeds to rekindle the debate on using terpenes for the development of environmentally friendly biopesticides and herbicides.
A lab bioassay was conducted in Agricultural engineering sciences college labs to study the allelopathic influence of wild oat (Avena fatua L.) different plant parts shoot, root and seeds aqueous ...extracts with five concentrations (0, 25%, 50%, 75% and 100%) on three plant species Lettuce, Onion and tomato seeds. Results indicated significant effect on all studied data, germination percentage, inhibition of germination, radicle length (cm); plumule length(cm); radicle dry eight, plumule dry weight; total seedlings dry weight (mg); radicle and plumule growth inhibition. The best bioassay plant was lettuce seeds for using as indicator in allelopathy studies. The main goal of the study was proposing five mathematical equations to indicate allelopathy index, the best two equations were chosen according to their best manipulation and demonstration based on total seedlings dry weight.
Leucena (Leucaena leucocephala) is an alternative used for animal feeding in the Northeastern of Brazil due to its resistance to drought and its high nutritional value. They are forest species whose ...seeds are affected by fungi that cause abnormalities and damage to seedlings, seed deterioration. The objective of this study was to evaluate the efficiency of essential oils in reducing the incidence of fungi associated with L. leucocephala seeds and their interference with physiological quality. The treatments were the following: essential oils of Cymbopogon nardus, Boswellia carteri, Eucalyptus globulus, Helianthus annuus, Vitis vinifera seeds, Eugenia caryophyllata, Melaleuca alternifolia and Rosmarinus officinalis in a concentration of 1 mL · L -1 and fungicide, using 100 seeds per treatment.In order to overcome dormancy scarification with sandpaper Nº 100 in the opposite region to the micropile. The sanitary quality of the seeds was made with the incubation method in Petri dishes containing double layer of filter paper moistened with ADE. Seed physiological quality was determined based on seed germination, emergence and vigor tests. The experimental design was completely randomized with ten treatments. Eucalyptus, clove and Melaleuca alternifolia essential oils reduced the incidence percentage of fungi associated with leucena seeds. Melaleuca alternifolia essential oil reduced the physiological quality of leucena seeds.
Plants may affect the performance of neighboring plants either positively or negatively through interspecific and intraspecific interactions. Productivity of mixed-species systems is ultimately the ...net result of positive and negative interactions among the component species. Despite increasing knowledge of positive interactions occurring in mixed-species tree systems, relatively little is known about the mechanisms underlying such interactions. Based on data from 25-year-old experimental stands in situ and a series of controlled experiments, we test the hypothesis that a broadleaf, non-N fixing species, Michelia macclurei, facilitates the performance of an autotoxic conifer Chinese fir (Cunninghamia lanceolata) through belowground chemical interactions. Chinese fir roots released the allelochemical cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-1,4-diazocane-2,5-diketone) into the soil environment, resulting in self-growth inhibition, and deterioration of soil microorganisms that improve P availability. However, when grown with M. macclurei the growth of Chinese fir was consistently enhanced. In particular, Chinese fir enhanced root growth and distribution in deep soil layers. When compared with monocultures of Chinese fir, the presence of M. macclurei reduced release and increased degradation of cyclic dipeptide in the soil, resulting in a shift from selfinhibition to chemical facilitation. This association also improved the soil microbial community by increasing arbuscular mycorrhizal fungi, and induced the production of Chinese fir roots. We conclude that interspecific interactions are less negative than intraspecific ones between non-N fixing broadleaf and autotoxic conifer species. The impacts are generated by reducing allelochemical levels, enhancing belowground mutualisms, improving soil properties, and changing root distributions as well as the net effects of all the processes within the soil. In particular, allelochemical context alters the consequences of the belowground ecological interactions with a novel mechanism: reduction of self-inhibition through reduced release and increased degradation of an autotoxic compound in the mixed-species plantations. Such a mechanism would be useful in reforestation programs undertaken to rehabilitate forest plantations that suffer from problems associated with autotoxicity.
Allelopathy between phytoplankton organisms is promoted by substances released into the marine environment that limit the presence of the dominating species. We evaluated the allelopathic effects and ...response of cell-free media of Chattonellamarina var. marina and Gymnodinium impudicum in the toxic dinoflagellate Gymnodinium catenatum. Additionally, single- and four-cell chains of G. catenatum isolated from media with allelochemicals were cultured to evaluate the effects of post exposure on growth and cell viability. Cell diagnosis showed growth limitation and an increase in cell volume, which reduced mobility and led to cell lysis. When G. catenatum was exposed to cell-free media of C. marina and G. impudicum, temporary cysts and an increased concentration of paralytic shellfish toxins were observed. After exposure to allelochemicals, the toxin profile of G. catenatum cells in the allelopathy experiments was composed of gonyautoxins 2/3 (GTX2/3), decarcarbamoyl (dcSTX, dcGTX2/3), and the sulfocarbamoyl toxins (B1 and C1/2). A difference in toxicity (pg STXeq cellsup.−1 ) was observed between G. catenatum cells in the control and those exposed to the filtrates of C. marina var. marina and G. impudicum. Single cells of G. catenatum had a lower growth rate, whereas chain-forming cells had a higher growth rate. We suggest that a low number of G. catenatum cells can survive the allelopathic effect. We hypothesize that the survival strategy of G. catenatum is migration through the chemical cloud, encystment, and increased toxicity.
•146 annotated features were significantly different in Microcystis aeruginosa-inhibited Aphanizomenon flos-aquae.•Several annotated differential features might be involved in growth inhibition and ...stress responses.•The concetrated M. aeruginosa culture fitrate probably inhibited Aphanizomenon via affecting multiple metabolites and pathways.
Microcystis and Aphanizomenon are two toxic cyanobacteria genera, which frequently cause blooms in freshwater lakes. In some cases, succession of these two genera was observed in natural water bodies. Among the diverse factors contributing to such succession of dominant cyanobacterial genera, an allelopathic effect was proposed to be involved after the growth inhibitory effect of several Microcystis species on A. flos-aquae was investigated. However, the response of target species exposed to Microcystis are poorly described. In the present study, we used two toxic cyanobacteria strains, Aphanizomenon flos-aquae (Aph1395) and Microcystis aeruginosa strain 905 (Ma905) as research subjects. Aph1395 was inhibited with a necessarily concentrated culture filtrate of Ma905 (MA905-SPE), and the response of the inhibited Aph1395 cells was explored via non-targeted metabolomic profiling. In total, 3735 features were significantly different in the Aph1395 treated with Ma905-SPE vs. those treated with BG11 medium. Among them, the annotations of 146 differential features were considered to be confident via MS/MS spectrum matching analysis. Based on the reported physiological functions of the annotated differential features, we proposed a putative model that in the growth-inhibited Aph1395, a suite of increased or decreased features with activities in apoptosis, growth inhibition, and stress response processes contributed to, or defended against, the allelopathic effect caused by Ma905. Our findings provide insights into the interaction between the bloom forming cyanobacterial species that share the same ecological environment.
The effects of different concentrations of ferulic acid, chlorogenic acid, and protocatechuic acid were studied in a pot experiment to assess the response of Rhododendron delavayi seedlings. The ...results showed that three kinds of phenols promoted increases in chlorophyll (Chl) a, Chl b, total Chl, and carotenoid contents, but inhibited the accumulation of biomass. Low concentrations of ferulic acid significantly inhibited stomatal opening, the stomatal opening ratio, stomatal length and width. Chlorogenic acid and the moderate and high concentrations of ferulic acid also significantly inhibited stomatal density. Ferulic acid significantly inhibited net photosynthetic rate and stomatal conductance in seedlings, whereas chlorogenic acid significantly inhibited stomatal conductance. The low and moderate concentrations of chlorogenic acid significantly inhibited transpiration rate, and high concentrations of ferulic acid significantly inhibited the stomatal limitation value. The moderate concentration of protocatechuic acid significantly inhibited net photosynthetic rate and stomatal conductance. Ferulic acid exhibited a greater toxic effect than that of chlorogenic acid and protocatechuic acid for R. delavayi seedlings.
An allelopathic rice PI312777 and a non-allelopathic rice Lemont were hydroponically cultured and treated with extracts of seeds and tissues and root exudates of barnyard grass (
Echinochloa ...crus-galli
, BYG) to induce an allelopathic response. The results of bioassays showed that the % inhibition of two rice leaf extracts was significantly (
p
< 0.05) increased by treatment with BYG root exudates. This induced trait was dosage- and time-dependent. The highest % inhibition for both PI312777 and Lemont was obtained following treatment with 15 mL of BYG root exudates for 2 days. Under these conditions, total allelopathy (TA) values of PI312777 on root length, plant height, and plant dry weight of BYG were 73.39, 68.01, and 70.42%, respectively, and induced allelopathy (IA) values were 21.53, 17.04, and 16.62%, respectively, accounting for 24–29% of TA. Correspondingly, TA values of Lemont were 28.38, 21.38, and 23.38%, respectively, and IA values were 14.49, 11.37, and 12.11%, respectively, accounting for 51–53% of TA. The % inhibition of two rice culture solutions was in agreement with the results of their leaf extracts. The total contents of 7 phenolic acids in the culture solutions of PI312777 and Lemont were 2.18 and 1.47 times, respectively, as much as those in the control solutions. The phenylalanine ammonia-lyase (
PAL
) gene in PI312777 leaves was significantly up-regulated after induction treatments. The results indicated that rice allelopathy is a chemical induction mechanism, and confirmed that chemical induction to raise rice allelopathy is a practical and feasible method.
Allelopathy (i.e. chemical interactions between plants) is known to affect individual performance, community structure and plant invasions. Yet, a quantitative synthesis is lacking. Here, we ...performed a meta‐analysis of 384 studies that measured allelopathic effects of one species (allelopathy plant) on another species or itself (test plant). Overall, allelopathy reduced plant performance by 25%, but the variation in allelopathy was high. The type of method affected the allelopathic effect: compared to leachates, allelopathy was more negative when residues of allelopathy plants were applied, and less negative when soil conditioned by allelopathy plants was applied. The negative effects of allelopathy diminished with study duration, and increased with concentrations of leachates or residues. Although allelopathy was not significantly related to lifespan, life form or domestication of the interacting plants, it became more negative with increasing phylogenetic distance. Moreover, native plants suffered more from leachates of naturalised alien plants than from leachates of other native plants. Our synthesis reveals that allelopathy could contribute to success of alien plants. The negative relationship between phylogenetic distance and allelopathy indicates that allelopathy might contribute to coexistence of closely related species (i.e. convergence) or dominance of single species.
Our meta‐analysis showed that allelopathy reduced plant performance by 25%, but the variation was high. The allelopathic effect was related to evolutionary history, indicating the role of allelopathy in species coexistence and plant invasion. We also reveal some major caveats in our current knowledge and provide suggestions for future studies.
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