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The present study was undertaken to assess the allelopathic effect of three Quercus species viz., Q. leucotrichophora , Q. floribunda and Q. serrata on germination and radicle-plumule growth of small millets ( Echinochloa frumentacea , Eleusine coracana and Amaranthus caudatus ) and one cereal crop wheat ( Triticum aestivum ) which are the major agricultural hill crops through laboratory bioassay. The aqueous extracts were prepared from the leaf and bark of the selected Quercus species and diluted to get 10, 25, 50, 75 and 100% concentrations. When increasing concentrations of leaf and bark extracts from 10 to 100%, it inhibited the germination and growth performance of test crops. Among the test crops, T. aestivum and E. frumentacea were found most susceptible while E. coracana and A. caudatus were the most resistant test crops. The leaf extracts were found to be more toxic in inhibiting germination and radicle-plumule growth of test crops as compared to bark extracts. The importance of these tree crops as prominent agroforestry tree species decreased in order Q. leucotrichophora < Q. floribunda < Q. serrata respectively Therefore, the results obtained within the scope of our study yielded sufficient preliminary evidence for considerable allelopathic effects from Q. floribunda and Q. serrata .

Trees enhance abundance of arbuscular mycorrhizal fungi, soil structure, and nutrient retention in low-input maize cropping systems

Study’s Excerpt/Novelty This study evaluates the allelopathic effects of Mangifera indica L. leaf leachate on the germination and early growth of various crops, offering detailed insights into concentration-dependent inhibitory effects. By identifying the differential sensitivity of chili peppers, soybeans, beans, okra, and maize to leaf leachate, the research suggests practical agricultural implications, particularly highlighting the potential of Mangifera indica as a natural herbicide. These findings contribute to a deeper understanding of plant-plant interactions and inform crop planting strategies to mitigate allelopathic effects in agricultural systems. Full Abstract This study evaluates the allelopathic effects of Mangifera indica L. leaf leachate on the germination and early growth of soybeans, beans, chili peppers, okra, and maize. Aqueous extracts were prepared from crushed mature leaves and tested at concentrations of 20%, 40%, 80%, and 100% compared to a control (distilled water). Germination percentage of the seeds was recorded at intervals of 24, 48, 76, and 92 hours, while shoot and root length were measured after 10 days. Results showed a concentration-dependent inhibition of germination and growth of shoot and root, with chili pepper being the most affected and maize the least. These findings suggest that Mangifera indica has potential as a natural herbicide and therefore recommended that soya beans, beans, okra, and especially chili pepper should not be planted at the very closest distance from the mango tree stem due to its allelopathic effects.

Mango (Mangifera indica L.) based agroforestry system offers spatial advantage for intercropping in Indian subtropics. Mango is planted at wide spacing to accommodate the large crowns needed to support the fruit yield. Wider spacing of the trees provides the vacant space to the orchardist to grow suitable and synergistic crop (vegetables/ medicinal plants) to supplement his income. The present investigation was done to screen out the best intercrop out of the four crops, viz. ginger, turmeric, kalmegh and stevia that can be grown in old mango orchards. The experiment was laid out at Experimental Farm of Advance Centre for Horticulture Research (ACHR), Sher-e-Kashmir University of Agricultural Sciences and Technology, Udheywala, Jammu, which is located at an altitude of 327m above mean sea level, between 32073´ N latitude and 74087´ E longitude. Mango orchard selected for the study had a very dense canopy and thus the interception of light was only 30-40 percent than that in the open. The results revealed that shade had profound influence on the survival, growth and yield of ginger, turmeric, stevia and kalmegh. The higher values for plant height, number of leaves, were recorded in ginger and turmeric under shade compared to stevia and kalmegh. Stevia had a very poor survival percentage (11.99%) under mango as compared to open. Likewise ginger had a poor survival percentage (13.22%) in the open compared to that under the mango canopy. Thus, it was concluded that under the subtropical conditions of Jammu region, ginger, turmeric and kalmegh can be grown successfully as intercrops under partial shade of mango trees, however, stevia cannot be integrated. The most remunerative crop among the four, in terms of yield was turmeric followed by ginger and kalmegh.

Understanding the nature of trees should provide an important step for improving the productivity of the components and designing agroforestry systems. The study was aimed to evaluate the impacts of parkland Christ's thorn and Mango trees species on the yield of sorghum within and outside the canopy of the tree in Harari Region Ethiopia. Accordingly, twelve trees (six for each) isolated and nearly similar Mango and Christ's thorn trees growing on more or less similar site conditions, management practices, canopy coverage and height were selected. Sorghum variety (bullo) which is dominantly grown around the study area was sown during rainy season along with existing both tree species in crop field. Three quadrates 1 m*1 m were laid out under, edge and outside the canopy of the trees in the sorghum farmland to assess the sorghum grain and biomass yield in parkland. The finding of the study also showed that the grain and biomass yield of sorghum were significantly (P<0.05) increased under canopy of Christ's thorn trees. Mango -sorghum interaction showed highly significant (p<0.01) reduction of sorghum biomass and grain yield under the tree canopy compared with open area. It can be concluded that the integration of trees particularly Mango with sorghum in parkland agroforestry should be promoted with effective tree crown management to reduce crop shading, particularly near the tree where the shading effect is high.

Allelopathic potential of aqueous extracts of lantana ( Lantana camara L. ) leaf on germination and growth of three agricultural crops: Maize, Finger millet and Tef, commonly cultivated in Ethiopia were studied under laboratory condition. The aqueous extracts were assayed at 5, 10, 25, 50 and 75% and their allelopathic effects were compared with distilled water (control). All the aqueous extracts did not significantly influence germination of the agricultural crops except 75% extract which significantly reduced germination of tef. All the leaf extracts stimulated root growth of maize and finger millet plants with the effect being declined with rise of concentration. In contrast, tef plants had reduced root growth in various leaf extracts with the highest reduction occurring at higher concentrations (25, 50 and 75%). The shoots of maize plants were also stimulated by all extract concentrations; whereas shoot growth of both tef and finger millet were not significantly affected by the leaf extracts. The results generally showed that lantana leaf extracts had stimulatory effects on early growth of maize and finger millet and inhibitory effects on tef growth. Keywords : Finger millet, Maize, Root growth, Shoot growth, Tef.

Salvia pratensis L. is a valuable medicinal plant rich in bioactive compounds, yet its allelopathic potential remains underexplored. This study evaluated allelopathic effects and total phenolic (TPC) and flavonoid (TFC) contents of water extracts from the dry aboveground biomass of S. pratensis. To assess their selectivity and potential application in sustainable weed management, extracts at five different concentrations were tested on the germination and early growth of lettuce, radish, tomato, and carrot. The results demonstrated that the phytotoxic effects of S. pratensis extracts were both concentration- and species-dependent. Higher extract concentrations significantly inhibited germination and seedling growth, while lower concentrations of extracts stimulated shoot elongation by up to 30% compared to the control. Phytochemical analysis revealed that S. pratensis extracts contain notable TPC and TFC contents, with their concentrations increasing consistently with the extract concentration. Correlation analysis showed that higher TPC and TFC contents were strongly negatively correlated with germination and seedling growth parameters. Radish exhibited the highest sensitivity to the extracts, while lettuce was the most tolerant. Further research under field conditions is needed to assess the efficacy, selectivity, and practical potential of S. pratensis extracts in sustainable crop production systems.

The spontaneous plant landscape is a key focus in the development of urban environments. While many spontaneous plants can coexist with bryophytes to create appealing wilderness landscapes, the potential allelopathic effects of bryophytes on the growth of neighboring spontaneous plants remain uncertain. This study evaluated the allelopathic impact of Thuidium kanedae aqueous extracts on the germination and seedling growth of prevalent urban spontaneous plants by analyzing seed germination, seedling growth morphology, and associated indices. We also investigated the allelopathic potential of the predominant compounds in the extract on seed germination. Our findings reveal that the aqueous extract significantly impeded the seed germination of Ophiopogon japonicus, Taraxacum mongolicum, and Viola philippica, with the level of inhibition correlating positively with concentration. In contrast, Senecio scandens seed germination showed a concentration-dependent reaction, with low concentrations promoting and high concentrations hindering germination. The extract consistently reduced root length in all four species, yet it appeared to increase root vigor. The chlorophyll content in O. japonicus and V. philippica seedlings reached a maximum at a concentration of 5 g/L and decreased with higher extract concentrations. The treatment resulted in elevated catalase and soluble protein levels in the seedlings, indicating that the extract induced stress and enhanced the stress resistance index. L-phenylalanine and 2-phenylethanol, substances present in the extract, were notably inhibitory to seed germination across all species, except for O. japonicus. Notably, 2-phenylethanol exhibited a stronger allelopathic effect than L-phenylalanine. Allelopathy synthetical effect evaluation showed that high concentration of aqueous extract allelopathic inhibition effect on seed germination of four plant species, but allelopathic promotion effect on physiological and biochemical growth of Taraxacum mongolicum, Senecio scandens and Viola philippica. In summary, the study demonstrates that bryophytes exert allelopathic effects on neighboring spontaneous plants, with the degree of influence varying among species. This suggests that the germination and growth of spontaneous plant seeds may be selective in bryophyte-dominated habitats and that the density of bryophytes could shape the evolution of these landscapes.

Weed incursion in cultivated fields is a serious biological problem, which causes considerable yield losses of economically important field crops through allelopathy and competitive interactions. Spotted knapweed (Centaurea maculosa) and yellow melilot (Melilotus officinalis) are among the most prevalent weeds in cultivated fields of Pakistan, particularly in wheat fields. Like many other weeds, they may pose allelopathic and competitive challenges to field crops. The objective of this study was to evaluate allelopathic potentials of the two weeds on germination and seedling growth of wheat under laboratory conditions. Amounts of 15, 20, 25 and 30% concentrated leaf aqueous extracts of C. maculosa and M. officinalis were prepared and tested for their effects on germination percentage, radicle and coleoptile lengths of wheat. Germination, radicle and coleoptile lengths of test crop declined significantly at higher concentration (25-30%) of the extracts of two weeds. However, concentration of M. officinalis up to 20% had either no effect or stimulatory effects on the studied growth characteristics of wheat. Highest germination inhibition and decreased seedling growth were caused by leaf extracts of C. maculosa at 30% extract concentration. Growth inhibition was generally dependent on the extract concentration. The study indicated that both plant exhibited allelopathic activity and growth inhibitory effects on wheat at higher concentration; however, extracts of C. maculosa were more phytoinhibitory than M. officinalis. The weeds could serve as potent allelopathic plants for management of other weeds.

Allelopathic effects of aqueous extract of different plant parts (root, stem and leaf) of Artemisia dubia on seed germination and seedling growth of two winter crops (Triticum aestivum and Brassica campestries, and some associated weeds (Bidens pilosa, Ageratum conyzoides, Galinsoga parviflora and Cyperus rotundus) have been investigated in the present study. Extracts of root, stem and leaves of Artemisia dubia showed significant reduction in germination and seedling growth of test crops and weeds. Germination of crop and weed seeds and growth of shoot and root were reduced significantly in test treatments in comparison to the control. The seed germination, shoot length and root length were low at higher concentration. Complete inhibition of seed germination of Ageratum conyzoides, Galinsoga parviflora and Cyperus rotundus at 5 and 10% leaf extract of A.dubia was observed. Allelopathic effects were more pronounced with leaf extract than root or stem extract in most cases.The result indicated difference in allelopathic effect on crop seed and weed seed at higher concentrations. ECOPRINT 21: 23-30, 2014DOI: http://dx.doi.org/10.3126/eco.v21i0.11901

The allelopathic effects of Lantana camara L. (Family:Verbenaceae) on germination and seedling establishment of some agricultural crops and weed species have been identified. Aqueous extracts of dry leaves and contaminated soil where L. camara is grown were used to verify allelopathic effect on seed germination of five bioassay species; Raphanus sativas, Capsicum annum, Lycopersicum esculantem, Crotalaria juncia and Chromoleana odorata. Fifty seeds from each bioassay species were placed in a petri dish containing leaf extracts or contaminated soil, and seed germination were examined after 3 days. The plant house experiments were carried out to evaluate the impact of L. camara contaminated soil and leaf debris using L. esculantem as the indicator plant. Seed germination of L. esculentem, C. junica and Capsicum annum was significantly inhibited by L. camara contaminated soil. However, the degree of inhibition varied among the bioassay species. The aqueous extract of dry leaves of L. camara was highly phytotoxic and it significantly reduced seed germination of all bioassay species. There was a decline in plant height, leaf area and shoot dry weight of tomato only in early growth stages when grown in L. camara contaminated soils. However, incorporation of leaf debris into soil affected the vegetative growth of tomato in early stages when the leaf debris concentration was increased. Growth recovered at the latter part of the life cycle. On the basis of these results it can be concluded that the allelochemicals in L. camara contaminated soils are harmful to the seed germination of crop species. The adverse effect was present only during the early growth stages and it did not suppress the latter part of the plant growth. These responses are attributed to allelopathic effects which need confirmation under field conditions.

The objective of this study was to understanding the allelopathic dynamic of invasive species Eupatorium adenophorum residues against traditional crops viz., Amaranthus caudatus and Vigna unguiculata in laboratory and green house. In laboratory, the effect of different concentrations of the aqueous extract and leaf leachate of decomposed residues (DR) and un‐decomposed residues (UDR) of the selected weed was examined on shoot and root length of the selected crops. In pot study, different concentrations of dose and leachate of DR and UDR of selected weed was evaluated against growth and yield performance of the studied crops. Shoot and root length of both crops was significantly reduced by the aqueous extract of both kinds of residues. Aqueous extract at 8% of UDR residues was noticed to be harmful to V. unguiculata and reduced 66.23% and 75.28% shoot and root length, respectively. Similarly, soil amended with DR and UDR of the weed had a significant effect on growth and yield attributes of the studied crops and reduced 64.90% growth and 86.30% branch/plant of V. unguiculata at 8% concentration compared to control soil. A significant amount of water‐soluble phytotoxins was found in the UDR and DR of E. adenophorum . Leaf leachate of the selected weed was more harmful as compared to aqueous extract and soil amended residues. The UDR was found to be more phytotoxic than DR. These results suggest that the phytotoxic potential of E. adenophorum to plant community could be minimized if the whole plant of invasive weed is decomposed.

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.

Plant species exhibiting allelopathic effects on weeds represent a promising approach for the development of environmentally sustainable bioherbicides. An invasive weed is a non-native species that, through its establishment or spread, has become harmful to native plants. Crop weed invasion reduced the potential for yield by releasing a particular chemical into the soil and competing for natural resources. The current study aimed to estimate the effect of different concentrations (0.0, 2, 4, 6, 8, and 10%) of the aqueous leaf extract of the therapeutic plant chamomile (Matricaria chamomilla L.) impact the pea (Pisum sativum L.) seedlings growth parameters, physiological and biochemical characteristics, mineral absorption, and antioxidant enzyme functions. The results showed the allelopathic effect of Chamomile leaves on seed germination and their diminishing effect on the prolines, total free amino acids, and growth parameters. Further, it also caused a surge in the expression of antioxidant enzymes, proteins, carbohydrates, K+, and Ca2+. Furthermore, there is a rise in lipid peroxidation and H2O2 levels at elevated extract concentrations. The strongest inhibiting or stimulating behaviors were observed at 8 and 10% concentrations of the extract. These results offer perspectives on the pea plant's reaction to the allelopathic influence of the herb Chamomile, thus categorizing Chamomile extract as an allelopathic variety.

We examined allelopathic effects and underlying mechanisms of Cinnamomum migao on its associated species Liquidambar formosana. We assessed effects of aqueous extracts of C. migao pericarp, leaf, and rhizosphere soil at different concentrations on seed germination, seedling growth, and physiology of L. formosana. All extracts inhibited L. formosana seed germination, with obvious inhibition at high concentrations (50 mg mL−1). All extracts promoted the height and ground diameter of seedlings, with the highest promotion achieved with aqueous leaf extract at a concentration of 1 mg mL−1 and aqueous pericarp and rhizosphere soil extracts at a concentration of 5 mg mL−1. All extracts promoted soluble protein accumulation in L. formosana seedlings, with the highest accumulation achieved with aqueous pericarp extracts. Aqueous leaf extract promoted soluble starch accumulation. Aqueous pericarp extract at concentrations of >10 mg mL−1 significantly increased soluble sugar content. Aqueous leaf and rhizosphere soil extracts at concentrations of >5 mg mL−1 increased proline accumulation. All extracts at concentrations of >1 mg mL−1 significantly increased malondialdehyde content. Aqueous pericarp and rhizosphere soil extracts at concentrations of 10 and 0.5 mg mL−1, respectively, promoted superoxide dismutase activity. Activities of soil urease, polyphenol oxidase, and catalase were significantly increased when the concentration of aqueous pericarp and leaf extracts exceeded 5 mg mL−1, and the activity of soil acid phosphatase significantly increased when the concentration of all extracts were 5 mg mL−1. According to the synthetic allelopathic index, the low- and medium-concentration extracts all showed a promoting effect, whereas high concentrations exhibited obvious inhibitory effects; furthermore, the comprehensive effect value of leaf water extraction was higher than that of the pericarp and rhizosphere soil. Thus, allelopathy can affect the long-term co-existence of C. migao and L. formosana.