Allelopathic Effects Of Aqueous Extracts Research Articles

Effect of Aqueous Extract of Ageratum Houstonianum on Seed Germination and Seedling Growth of Triticum Aestivum (Wheat)

Invasive plants are species that do not belong in a particular habitat but enter and establish themselves there. They are known for their adaptability and competitiveness in different environmental conditions. They tend to compete with crops for crucial resources, including water, light, and nutrients and can hinder crop growth and development through allelopathy. The aim of the current research was to investigate the allelopathic effect of aqueous extracts of Ageratum houstonianum on the germination and growth of wheat (Triticum aestivum) seedlings. The aqueous extracts were obtained from the leaves of A. houstonianum at various concentrations, including control, 25%, 50%, and 100%, and applied to pot and petri-plates cultures. The experiment was set up with 5 replicates for both the Petri plates and pot cultures. The study results showed that A. houstonianum aqueous leaf extracts had a significant impact on the germination and growth of T.aestivum. The concentrated (100%) aqueous leaf extracts of A. houstonianum significantly hindered the germination of seeds and growth parameters of T. aestivum. Additionally, the extract treatments of the weed species resulted in changes in soil pH and soil fertility. When invasive weed species grow alongside crops in fields, they may consume a significant number of resources required for crop growth, leading to a decrease in both the quantity and quality of agricultural output. Hence, this study highlights the potential adverse effects of invasive weeds on crop growth and development, and how they can negatively impact agricultural productivity. Therefore, there is a need for effective management strategies to control the spread of invasive weed species and preserve the productivity of agricultural land.

Allelopathic effects of aqueous extracts from uncomposted and composted Mexican devil (Ageratina adenophora) plants on forest fungal growth and soil nitrogen and phosphorus mobilization

AbstractMexican devil [Ageratina adenophora (Spreng.) R.M. King & H. Rob.], a globally invasive weed with destructive effects on forests, has spread to numerous countries. To elucidate the inhibition of tree growth by A. adenophora, a study was conducted using the fungi (Lactarius deliciosus, Ceriporia lacerata, and Fomitopsis palustris) involved in the recycling of carbon and nutrients in forests. The focus was on investigating soil nitrogen and phosphorus availability in response to aqueous extracts from uncomposted and aerobically composted A. adenophora (EUA and ECA, respectively). The samples of composted A. adenophora from different sites exhibited a significant reduction in the concentration of allelochemicals 4,7-dimethyl-1-(propan-2-ylidene)-1,4,4a,8a-tetrahydronaphthalene-2,6(1H, 7H)-dione and 6-hydroxy-5-isopropyl-3,8-dimethyl-4a,5,6,7,8,8a-hexahydronaphthalen-2(1H)-one. This reduction more than 94% when compared with the concentration of these allelochemicals in CA. The EUA solutions at 5 and 10 mg L−1 (oven-dried plant biomass base) minimized L. deliciosus and C. lacerata growth, and significantly decreased F. palustris growth on the soil surface and within the soil. However, soil with ECA had no effect or promoting effect on the fungal growth. Compared with CK (only fungal inoculation in tested soil), the EUA solution reduced soil nitrogen and phosphorus, while ECA had the opposite effect; soil pH was increased by 0.01 to 0.08 under EUA treatment, while it decreased by 0.5 to 0.41under ECA treatment. Nitrogen and phosphorus availability were positively correlated with protease and phosphatase activity (r = 0.723 to 0.944), while available phosphorus was inversely correlated with pH in tested soils (r = -(0.809 to 0.978)). As such, the EUA solution decreased soil nitrogen and phosphorus supplies by inhibiting the liberation of proteases, phosphatases, and protons, which may lead to poor growth or even mortality of three fungal species. The in situ aerobically composted A. adenophora residues left behind may directly supply fungal species with nutrients and indirectly increase soil nutrient availability via the promotion of nitrogen and phosphorus mobilization.

Allelopathic effect of aqueous extracts of common sunflower on seed germination and growth of field pea

Allelopathic effect of aqueous extracts of common sunflower on seed germination and growth of field pea

The Allelopathic Activity of Aqueous Extracts of Helianthus annuus L., Grown in Boreal Conditions, on Germination, Development, and Physiological Indices of Pisum sativum L.

Evaluation of the allelopathy relationship between different crops is a sensible strategy fallowing the correct use of positive effects and to avoid the disadvantageous effects among plants. This study aimed to detect the allelopathic effect of aqueous extracts of sunflower (Helianthus annuus L.), grown in a boreal climatic zone, on the growth, subsequent development, and physiological traits of pea (Pisum sativum L.). Three factors have been studied: donor plant fertilization (unfertilized and fertilized), aqueous extracts from donor plant organs (leaves and stems (L+S), heads (H) and roots (R)); four concentrations of extracts (0%, 25%, 50% and 75%). The aqueous extracts from fertilized sunflower donor plant at 25% and 50% concentration acted as potential biostimulants that stimulated pea seed germination (SG), whereas L+S and R extracts at 75% concentration from unfertilized donor plant inhibited SG, at 4 days after sowing. The aqueous extracts demonstrated a stimulating effect on above-ground and root dry mass, compared to the control. The concentration of extracts demonstrated a significant inhibitory effect on SPAD. R extract revealed the strongest allelopathic effect on physiological traits of pea. L+S and H extracts at 25% concentration had stimulating effects, while 50% and 75% concentrations showed inhibiting effects on the photosynthetic rate. The water use efficiency, stomatal conductance, and stomatal limitation were inhibited, whereas, the transpiration rate, photosynthetic water use efficiency and intercellular CO2 concentration were stimulated, with an increasing of extract concentrations, comparatively to the control.

Allelopathic effect of aqueous extract of Polygonum bistorta and Terminalia chebula on germination and seedling growth of Daucus carota and Medicago polymorpha

Weed management is essential for sustainable crop production in all cropping systems. The use of herbicides is causing the problems of herbicide resistant weeds and environmental pollution. Plant-released phytotoxins have ability to promote or inhibit the germination and seedling growth of surrounding crops and weeds. Therefore, it is imperative to identify plant species having the herbicidal potential to use as more safe and sustainable weed management approach. The present study was planned in 2018 to investigate the germination and seedling growth of Daucus carota and Medicago polymorpha influenced by the root extract of Polygonum bistorta and fruit extract of Terminalia chebula. Different concentrations of aqueous extract (0, 2.5, 5, 10, 20, 40 and 80%) significantly reduced the germination and seedling growth of target species. Results of these experiments revealed that thefruit extract of T. chebula was more phytotoxic as compared to root extract of P. bistorta regarding seedling growth of weed. However, fruit extract of T. chebula having 80% concentration fully inhibit the germination of D. carota and M. polymorpha. One the bases of these finding it was concluded that the fruit extract of T. chebula and root extract of P. bistorta have comparatively more active substances with ability to suppress germination and growth of plants which could be exploited as prospective source of bio-herbicides.

Allelopathic Effect of Aqueous Extract of Parkia Biglobosa (L.) on Some Weeds in Gombe State, Nigeria

This study examined the allelopathic effect of different concentration of aqueous extracts of Parkia biglobosa stem bark on the germination and growth of weed seeds species. Seeds of Eragorastis tenella, Eragorastis atrovirens, Pannicum pedicellata, Pennisetum sub albidum, Hypharrhenia rufa and Brcichiaria brizantha were tested for plumule germination and radicle growth with three different concentrations of 1%, 5%, 10% plant extract while ordinary water was used as control. Growth parameters including germinated weeds population were measured; the highest germinated weeds population was at the control (8.06±3.97) and the least was obtained from the 10% concentration with the mean of (4.42±2.59). Weeds population decreased as the concentration increased. The highest mean of weeds height was recorded from 1% concentration (11.46±7.08) which is statistically significant while the least mean was recorded from 10% concentration (7.69±6.70) statistically not significant. The family emergence by concentration indicated that, the experiment under control had (4 families) for 1% (2 families), 5% (2 families) and 10% (4 families) emerged. The germination, radicle and plumule length were inhibited when compare with control and the inhibition was statistically not significant at.

Allelopathic Effects of Aqueous Extract from Satureja thymbra L. on Seed Germination and Seedling Growth of Pinus halepensis Mill. and Ceratonia siliqua L

The objective of this study was to determine the impact of allelopathic potentials of aqueous extract of Satureja thymbra L. aerial parts on seed germination of Ceratonia siliqua L. and early growth seedling of Pinus halepensis Mill. and Ceratonia siliqua L. Satureja thymbra L. aerial parts were collected from Al-Jabal Al-Akhdar, Libya and collected aerial parts were dried and powdered. The treatments included 100%, 50% and 25% aqueous extracts along with water as a control. One-way analysis of variance (ANOVA) was performed and Regression analysis between treatments vs. root length, shoot length, and number of leaves among Pinus halepensis Mill and Ceratonia siliqua L. were done. The results showed seed germination of Ceratonia siliqua decreased by increasing extract concentration. The highest and lowest seed germination was belonged to control and 100 % extract respectively. In addition, the result showed a significant difference between treatments in root length and the number of leaves of both species. The LSD test showed that root length and number of leaves of Pinus halepensis Mill. and Ceratonia siliqua L. at treatments of 25%, 50% and 100% was significantly different from control. The regression analysis between root length, and number of leaves in Pinus halepensis Mill. and Ceratonia siliqua L. were significantly reduced with the increase in the extract concentration. The results demonstrate that previously mentioned extracts have inhibitory effects on the growth of roots and shoots of Pinus halepensis Mill. and Ceratonia silique L. Thus, it is recommended to use from residual of medicinal plant or select them in crop rotation systems to weed by allelochemicals compounds.

Testing an Allelopathic Effect Arum Cyreniacum on Germination and Growth of Pisum Sativum LTesting an Allelopathic Effect Arum Cyreniacum on Germination and Growth of Pisum Sativum L

Two experiments were conducted (laboratory - pots) at the lab of the biology Department/ Faculty of education/ Omar Al-Mukhtar University/ Al Bayda/ Libya, to aim testing allelopathic effects of aqueous extracts at concentrations of (6, 8 and 10%), adding the Crude powder to soil at a concentration of (3%) of (Tubers-Leaves) Arum cyreniacum on the germination of seeds and development seedlings of Pisum sativum with three replications according to a completely randomized design. The results of the laboratory experiment showed were significant differences in reduction of germination percentage, reduction of radical and plumule lengths between aqueous extracts, compared with control, also, all concentrations caused a clear delay in an average germination time. The results of a pots experiment showed a concentration (3%) reduced the percentage emergence of seedlings, and decrease root and shoot lengths, fresh and dry weights of seedlings. A concentration (3%) caused a decrease of content chlorophyll (a, b), and sodium, an accumulation of carotenoids, potassium and iron, compared to the control. The leaves had the highest inhibition rates compared to the tubers at inhibiting the growth of studied traits. This study concluded that A. cyreniacum has inhibitory effects against germination of P.sativum.

Volatile and Non-Volatile Allelopathic Characteristics in Thermally Processed Needles of Two Conifers.

With allelopathic composts, potential merits for preventing initial weed infestations have been observed in crop transplantation. However, previous studies have rarely investigated whether high temperatures, generated during composting, decrease allelopathic ability. This study evaluated the thermal allelopathic effect of two coniferous plants (Pinus densiflora and P. koraiensis) on Brassica napus germination and seedling growth using their characterized allelochemical destinations. The 90 °C dry treatment of P. densiflora extract exhibited stronger inhibitory effect on germination than its 30 °C dry treatment. In a range from 0.25 to 1 mg mL−1, the germination rate was decreased to 38.1 and 64.3% of control with P. densiflora extract dried at 90 and 30 °C, respectively. However, P. koraiensis showed potent inhibition of the germination process with no statistical difference in inhibitory effects regardless of the dry temperature. Regarding B. napus seedling root growth, the allelopathic effects of aqueous extracts of both conifers were not reduced with the 90 °C treatment, but it was lost in seedling shoot growth. GC-MS/MS confirmed that high temperature treatment drastically decreased volatile contents to 53.2% in P. densiflora, resulting in reduced allelopathic abilities. However, a relatively lower decrease to 83.1% in volatiles of P. koraiensis accounts for less loss of the root-specific inhibitory effect on B. napus seedlings even after 90 °C treatment. Foliar tissues of both conifers with species-specific thermal resistance have potentially valuable functions regarding allelopathic use in horticultural compost processing ingredients, demonstrating their weed control ability during the early cultivation season where crops are transplanted in the facilitated area.

The impact of grazing intensity on the allelopathic effect of Artemisia frigida in a temperate grassland in northern China

Allelopathy is an important factor affecting plant community structure. However, few studies have focused on the mechanisms of allelopathy in the process of community succession driven by different grazing intensities. Therefore, field sampling, indoor experiments and field control experiments were conducted in a temperate grassland in northern China. We aimed to detect the impact of different grazing intensities on the chemical components and allelopathic effect of aqueous extracts of Artemisia frigida. The seed germination rate, radicle length, plant height and biomass of the four tested plant species were used to quantify the allelopathic effect of A. frigida. Grazing intensity altered the composition and concentration of chemical components contained in aqueous extracts of A. frigida. The maximum relative contents of 1,8-cineole and β-terpineol both occurred under heavy grazing. The allelopathic effect of A. frigida varied significantly among different grazing intensities and tested species, and the interaction effects between grazing intensity and tested species were also significant. The allelopathic effects of A. frigida significantly influenced the seed germination rate and radicle length of all the test species except Medicago sativa. The aqueous extracts of A. frigida also significantly affected the aboveground, belowground and total biomass of M. sativa and Melilotus officinalis. The allelopathic effect of A. frigida significantly promoted its own plant biomass and inhibited the plant biomass of Stipa krylovii. Our results confirmed that the allelopathic effects of A. frigida partly regulated the process of species composition in degraded rangelands.

Allelopathic effects of weed spp on the root border cells of Fagopyrum tataricum (L.) Gaertn

We studied the allelopathic effects of aqueous extracts of Galinsoga parviflora Cav., Chenopodium ambrosioides L., and Bidens pilosa L. weed species on the developmental characteristics of Tartary buckwheat RBCs. The increase in the concentration of aqueous extracts, there was increase in apoptosis rate and mucigel thickness of the RBCs, level of intracellular reactive oxygen species and nitric oxide, but decreased the mitochondrial membrane potential (P <0.05). The allelopathic effects of aqueous extracts of donor weed species on RBCs followed the order: C. ambrosioides > B. pilosa > G. parviflora. The increased levels of reactive oxygen species, nitric oxide and the reduced potential of mitochondrial membrane, further disrupted the homeostasis and normal metabolism of cells, thereby inducing the cell death. Among the three weed species, C. ambrosioides had the most significant impact

Allelopathic Effects of Castanea henryi Aqueous Extracts on the Growth and Physiology of Brassica pekinensis and Zea mays.

The present study investigated the allelopathic effects of aqueous extracts of Castanea henryi litter on the growth and physiological responses of Brassica pekinensis and Zea mays. Treatment with high concentrations of leaf extract (0.05 g/ml for B. pekinensis and 0.10 g/ml for Z. mays) significantly increased malonaldehyde content and reduced seed germination, seedling growth, chlorophyll content, and the activity levels of antioxidant enzymes. These effects generally increased with increasing extract concentration. However, in Z. mays, low extract concentrations actually promoted seed germination, shoot growth, chlorophyll content, and antioxidant enzyme activity. The allelopathic effects of the various C. henryi extracts decreased as follows: leaf extract > twig extract > shell extract. Eleven potential allelochemicals including rutin, quercetin, luteolin, procyanidin A2, kaempferol, allantoin, propionic acid, salicylic acid, jasmonic acid, methylmalonic acid, and gentisic acid were identified in the leaves of C. henryi which were linked to the strongest allelopathic effects. These findings suggest that the allelopathic effects of C. henryi differ depending on receptor plant species, and that leaves are the most allelopathic litter in C. henryi.

Allelopathic effect of aqueous extract of Cyperus rotundus on Lactuca sativa and Solanum lycopersicum

The demand for vegetables was reinforced by the search for healthier foods, favoring increased sales of fresh products. Lettuce ( Lactuca sativa L.) and tomato ( Solanum lycopersicum L.) are the most cultivated vegetables in Brazil, thus being economically important. This study evaluates the allelopathic effect of aqueous extract of nutgrass ( Cyperus rotundus ) on lettuce ( Lactuca sativa ) and tomato ( Solanum lycopersicum ) plants, aiming to ana­lyze its influence on species development. Two trials were conducted in the premises of the Taquaritinguense Institute of Higher Education (ITES) in Taquaritinga city, Sao Paulo State, under temperatures ranging from 14 oC to 28 oC, in a greenhouse. The variables analyzed were: fresh shoot and root weight (g), using a semianalytical scale; and root length (cm), using a ruler. Cyperus rotundus leaf extract at higher concentrations positively affected the early growth of vegetables. Studies on allelopathic effects between plants are extremely important because the use of this extract can contribute to seedling growth. The 200% concentration of Cyperus rotundus extract increased root and shoot development in tomato crop.

Phytochemical Profile and Evaluation of the Allelopathic Effect of the Aqueous Extract of Fimbristylis miliacea (L.) Vahl (Cyperaceae)

The allelopathic potential of some plant species has been scientifically proven over the years. The use of such natural compounds with phytotoxic activity is an alternative to synthetic herbicides. Thus, this research aims to analyze the phytochemical profile and the allelopathic effect of aqueous extracts of Fimbristylis miliacea (L.) Vahl. The allelopathic potential was evaluated by germination bioassays using seeds from two receptor species (Lactuca sativa L. and Emilia fosbergii Nicolson) and seven concentrations of aqueous extracts of F. miliacea aerial and underground parts in triplicate. The variables evaluated were germination (G) and germination speed index (GSI). The data obtained were submitted to F test and the averages to regression analysis. In addition, phytochemical analyses were performed to analyze possible allelochemicals present in aqueous extracts of F. miliacea through phytochemical screening and by high performance liquid chromatography (HPLC). The aqueous extracts of aerial and underground parts of F. miliacea inhibit the germination of E. fosbergii seeds at all concentrations analyzed (0.94, 1.87, 3.75, 7.5, 15 and 30%). However, the same extracts do not show any effects when evaluated in L. sativa seeds. The aqueous extract of F. miliacea shows important chemical constituents (gallic acid, chlorogenic acid, rutin, luteolin, apigenin, acacetin, and alkaloids) that can be directly related to the allelopathic effects observed in E. fosbergii seeds.

Allelopathy of weeds on the growth of vegetables

The use of allelopathy emerges as an alternative method for weed management in crops, especially in small vegetable producing properties. Thus, the objective of this work was to identify possible allelopathic effects of aqueous extracts of the weeds Cyperus difformis L. (small-flowered nutsedge), Commelina benghalensis L. (benghal dayflower) and Galinsoga parviflora Cav. (gallant soldier) on seed germination and seedling growth of Lactuca sativa L. (lettuce) and Lycopersicum esculentum L. (tomato). Two experiments were carried out in a completely randomized design with five replications, the first with lettuce seeds and the second with tomato seeds submitted to germination in five concentrations of weeds aqueous extracts (0, 25, 50, 75 and 100%). All treatments with aqueous extracts of the three species, at different concentrations, caused a reduction in lettuce and tomato root length. There was a reduction in most of the evaluated variables, and seed germination of the crops had the lowest influence of the extracts. The weeds benghal dayflower, small-flowered nutsedge and gallant soldier showed allelopathic potential on lettuce and tomato crops. This potential allelopathic effect is directly related to the concentration and type of extract from the plant species. In general, it can be noted that the greatest allelopathic effect occurred with the use of small-flowered nutsedge extract, followed by gallant soldier and benghal dayflower.

Allelopathic Effects of Pigweed (Amaranthus viridis L.) on Seed Germination and Seedling Growth of some Leguminous Crops

Laboratory and greenhouse experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15. Laboratory experiments were conducted to study the allelopathic effects of aqueous extract of aboveground parts of pigweed (Amaranthus viridis L.) on seed germination of common bean (Phaseolus vulgaris L.), cowpea (Vigna sinensis [L.] Walp.), pigeon pea (Cajanus cajan [L.] Millsp.) and alfalfa (Medicago sativa L.). Six concentrations (0, 20, 40, 60, 80 and 100%) of the aqueous extract of aboveground parts were prepared from the stock solution (50 g / l). Treatments, for each crop, were arranged in completely randomized design with four replicates. The seeds were examined for germination at three days after initial germination. Greenhouse experiments were conducted to study the allelopathic effects of powder of aboveground parts of pigweed on seedling growth of the same crops. Powder of aboveground parts was incorporated into the soil at rate of 0, 1, 2, 3, 4 and 5% on w/w bases in pots. Treatments, for each crop, were arranged in completely randomized design with four replicates. Experiments were terminated at 30 days after sowing and plant height, number of leaves and root length of crop seedlings were measured as well as plant fresh and dry weight. Data were collected and subjected to analysis of variance procedure. Means were separated for significance using Duncan`s Multiple Range Test at p  0.05. The results showed that the aqueous extract of aboveground parts of pigweed significantly reduced seed germination of the tested leguminous crops and there was direct negative relationship between concentration seed germination. Also, the results showed that incorporating powder of aboveground parts into the soil significantly decreased plant height and root length of crop seedlings as well as seedling fresh and dry weight. In addition, the reduction in seedling growth was increased as the powder increased in the soil. Based on results supported by different studies, it was concluded that pigweed has allelopathic affects on seed germination and seedling growth of the leguminous crops.

Allelopathic effect of aqueous extracts of Canadian goldenrod on germination and growth of radish

In this study we tested the effects of Solidago canadensis extracts on seed germination and early growth of radish (Raphanus sativus). The aqueous extracts of 2.5% (m/v) concentration were prepared from roots, rhizomes, stems, leaves and inflorescences and applied onto the filter paper in Petri dishes where radish seeds were sown. We determined the germination rate and seedling growth for four days. The extracts from leaves and inflorescences delayed germination, whereas extracts from stems and roots had no significant effect on seed germination. The extracts from rhizome had a slightly stimulatory effect on the seed germination and promoted shoot length of radish seedlings, while extracts from leaves inhibited root and shoot length and seedlings development.

Morphological and Biochemical Study of Bidens pilosa on the Effects of Extract of Urochloa ruziziensis

Bidens pilosa is an aggressive species that competes with crops and, in addition, has a high capacity to acquire resistance or tolerance to herbicides. Thus, the objective of the present study was to investigate the allelopathic effects of aqueous extract of Urochloa ruziziensis on germination, development, respiration, antioxidant enzymes and cells morphology of B. pilosa seedlings during initial growth at laboratory.The seeds were sown with water or U. ruziziensis extract at concentrations of 250, 500 and 900 ppm, and after four days the percentage of germinated seeds, root and hypocotyl development, as well as respiration, peroxidase and catalase activity by seedlings, were analysed. The results were submitted to analysis of variance (ANOVA) and the means compared by the Tukey test and regression analysis. The cellular structures of the root with U. ruziziensis extract treatment (0, 500 and 900 ppm) were also analysed by transmission electron microscopy. The application of the extract reduced the germination of the seeds. The root growth increased, however, there was a reduction in the dry matter mass at 500 ppm. Mitochondrial respiration decreased and there was an increase in the activity of the peroxidase and catalase enzymes at 500 ppm. Morphological changes in the cells were also found, mainly with this concentration. Thus, it is possible can be concluded that allelochemicals present in extract from U. ruziziensis have the potential to provoke oxidative stress in B. pilosa seedlings in laboratory, mainly at a concentration of 500 ppm. This oxidative stress caused alterations mainly in the energetic metabolism of this plant, being this a primordial factor for its growth and survival.

Efeito alelopático de Leucaena leucocephala e Hovenia dulcis sobre germinação de Mimosa bimucronata e Peltophorum dubium

The aim of this study was to determine the allelopathic effect of aqueous extracts of leaves of Leucaena leucocephala (Lam.) R. de Wit. and Hovenia dulcis Thunb. on germination and early development of Mimosa bimucronata DC Kuntze and Peltophorum dubium (Spreng.) . Extracts were prepared in dilution of 2.5%; 5%; 7.5% and 10% (w/v) and compared to the control. Both extracts revealed allelopathic potential on seed germination and initial growth of M. bimucronata. No negative interference of extracts from the donor species was observed on the germination of P. dubium. However, seedlings subjected to L. leucocephala extract suffered interference in the initial development, resulting in the elongation of the radicle to be more sensitive to the effects of the extracts. Thus, the results showed that aqueous extracts of the leaves of L. leucocephala and H. dulcis have inhibitory properties on germination and early development of M. bimucronata, as well as and early development of P. dubium

Allelopathic Effects of Jimsonweed (Datua Stramonium L.) Seed on Seed Germination and Seedling Growth of Some Leguminous Crops

Laboratory and greenhouse experiments were carried out at the Faculty of Agricultural Sciences, University of Gezira, Sudan in season 2014/15. Laboratory experiments were conducted to study the allelopathic effect of aqueous extract of Jimsonweed (Datua stramonium L.) seed on seed germination of common bean (Phaseolus vulgaris L.), cowpea (Vigna sinensis [L.] Walp.), pigeon pea (Cajanus cajan [L.] Millsp.) and alfalfa (Medicago sativa L.). Six concentrations (0, 20, 40, 60, 80 and 100%) of the aqueous extract were prepared from the stock solution. Treatments, for each crop, were arranged in completely randomized design with four replicates. The seeds were examined for germination at three days after initial germination. Greenhouse experiments were conducted to study the allelopathic effect of Jimsonweed seed powder on seedling growth of the same crops. Seed powder was incorporated into the soil at rate of 0, 1, 2, 3, 4 and 5% on w/w biases in pots. Treatments, for each crop, were arranged in completely randomized design with four replicates. Experiments were terminated at 30 days after sowing and plant height, number of leaves and root length of crop seedlings were measured as well as plant fresh and dry weight. Data were collected and subjected to analysis of variance procedure. Means were separated for significance using Duncan`s Multiple Range Test at p £ 0.5. The results showed that the aqueous extract of Jimsonweed significantly reduced seed germination of the tested leguminous crops and there was direct negative relationship between concentration seed germination. Also, the results showed that incorporating seed powder into the soil significantly decreased plant height, root length of crop seedlings as well as seedling fresh and dry weight. In addition, the reduction in seedling growth was increased as seed powder increased in the soil. However, the number leaves did not affected. It concludes that Jimsonweed has allelopathic affects on seed germination and seedling growth of the leguminous crops.