Is Juglone the Only Naphthoquinone in Juglans regia L. with Allelopathic Effects?

We investigated whether juglone is the only allelochemical in a leaf extract from the walnut (Juglans regia L.). This was achieved through comparisons of the effects of pure juglone (1 mM, 100 μM, 10 μM control juglone) and J. regia leaf extract (prepared as 1 mM, 100 μM leaf juglone) on seed germination, seedling growth, and secondary metabolism of the selected crop vegetables. Two control treatments were also applied, as extraction medium and water. For inhibition of seed germination, S. lycopersicum, B. rapa var. japonica, and V. locusta were more sensitive to 1 mM leaf juglone, and L. sativa was more sensitive to 1 mM control juglone. This suggests that this walnut leaf extract contains specific phenolic substance(s) that can stimulate seed germination in some species and inhibit it in others. Seedling length was more sensitive to 1 mM leaf juglone than 1 mM control juglone, with selective strong inhibition of root length versus shoot length by 1 mM control juglone. Juglone also had significant effects on the secondary metabolism of L. sativa, in particular for seedlings treated with 100 μM control juglone, with marked decreases in all secondary metabolites studied. Flavonols constituted the majority of these metabolites in L. culinaris, which showed the least sensitivity to both control juglone and leaf juglone treatments. Thirty compounds were identified and quantified in S. lycopersicum, L. culinaris, and L. sativa, some for the first time in these plants, and all for the first time in the seedlings of these crop vegetables.

Download Full-text

Allelopathic Potency and an Active Substance from Hairy Vetch

Legume Research - An International Journal ◽

10.18805/lr-548 ◽

2020 ◽

Author(s):

Weihong Sun ◽

Guofeng Yang ◽

Lili Cong ◽

Juan Sun ◽

Lichao Ma

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Root Length ◽

Leaf Extract ◽

Growth Inhibitor ◽

Inhibitory Effect ◽

Allelopathic Effect ◽

Coumaric Acid ◽

Hairy Vetch ◽

Allelopathic Effects

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.

Download Full-text

ALLELOPATHIC POTENTIAL OF Cyperus rotundus L. EXTRACTS ON GERMINATION AND COWPEA SEEDLING ESTABLISHMENT

Nativa ◽

10.31413/nativa.v6i3.4708 ◽

2018 ◽

Vol 6 (3) ◽

pp. 261

Author(s):

João Alves Ferreira Pereira ◽

Tatiana Maria da Silva ◽

Andreza Raquel Barbosa de Farias ◽

Alexandre Bosco de Oliveira

Keyword(s):

Seed Germination ◽

Vigna Unguiculata ◽

Early Growth ◽

Shoot Length ◽

Cyperus Rotundus ◽

Control Treatment ◽

Root Weight ◽

Allelopathic Potential ◽

Germination Speed ◽

Allelopathic Effects

POTENCIAL ALELOPÁTICO DE EXTRATOS DE Cyperus rotundus L. NA GERMINAÇÃO E ESTABELECIMENTO DE PLÂNTULAS DE FEIJÃO-CAUPI Este trabalho investigou os efeitos alelopáticos de extratos de Cyperus rotundus L. na germinação de sementes e crescimento inicial das plântulas de Vigna unguiculata L. Walp. Extratos alcoólicos nas concentrações 0; 1,5%; 3,0%; 4,5%; 6,0%; 7,5% e 9,0%, obtidos a partir da trituração de folhas de C. rotundus L. foram utilizados para umedecimento das folhas de papel toalha “germitest”. Os dados foram submetidos a análise de variância pelo F e as médias comparadas pelos testes de Tukey e Kruscal-Wallis, ambos a 5% de probabilidade. A primeira contagem de germinação, índice de velocidade de germinação, comprimento de raiz, comprimento da parte aérea e massa seca da raiz do feijão-caupi foram analisados de forma paramétrica, sendo constatado que apenas houve significância na variável primeira contagem e uma redução na germinação em relação ao tratamento controle em torno de 10%. Nas condições em que essa pesquisa foi realizada, os extratos alcoólicos de C. rotundus L. não afetam a germinação de sementes e crescimento inicial das plântulas de feijão-caupi.Palavras-chave: tiririca, alelopatia, interferência, plantas daninhas. ABSTRACT:This study aimed to investigate the allelopathic effects of Cyperus rotundus L. extracts on seed germination and early development of seedlings of Vigna unguiculata L. Walp. Alcoholic extracts at concentrations of 0, 1.5%, 3%, 4.5%, 6.0%, 7.5%, and 9.0% were obtained by crushing C. rotundus L. leaves used to moisten the “germitest” paper sheets. The data were subjected to analysis of variance and also both Tukey and Kruscal-Wallis tests were carried out at 5% for the data means. The first germination count, germination speed index, root length, shoot length, and dry root weight of cowpea were parametrically analyzed. The only variable with significance was first germination count. The germination reducted in relation to the control treatment around 10%. Thus, in the conditions used in this research, alcoholic extracts of C. rotundus L. did not affect either seed germination or early growth of cowpea seedlings.Keywords: nut grass, allelopathy, interference, weeds. DOI:

Download Full-text

Propagation and Possible Allelopathic Effects of Vernoniazeylanica on Selected Bioassay Species

CORD ◽

10.37833/cord.v36i.428 ◽

2020 ◽

Vol 36 ◽

pp. 41-46

Author(s):

S.H.S. Senarathne ◽

S. S. Udumann

Keyword(s):

Seed Germination ◽

Plant Species ◽

Seedling Growth ◽

Contaminated Soil ◽

Leaf Extract ◽

Cocos Nucifera ◽

Test Plant ◽

Allelopathic Effect ◽

Aqueous Leaf Extract ◽

Allelopathic Effects

Vernonia zeylanica (L.) belongs to the family Asteraceae, is one of the major endemic weed species present in coconut (Cocos nucifera L.) plantations of the tropics, which propagates very easily. There is a possibility that this plant could also possess allelopathic effects, but this has not been scientifically tested. Thus, a study was carried out to determine the seed germination of V. zeylanica under soil moisture stress conditions, shoot propagation methods and possible allopathic effects of this species, on selected species in bioassay tests. Germination of V. zeylanica seeds was not observed at higher osmotic potential (-0.9 MPa). The highest sprouting percentage of this species were obtained with soft wood cuttings. The aqueous leaf extract was highly phytotoxic, and it significantly reduced germination and seedling growth of all bioassay species tested. Full strength (33.3 g L-1) aqueous extracts of leaves significantly reduced the germination percentage, root and hypocotyl growth rates of all species tested. The inhibitory effects were often dependent on concentration. However, the degree of inhibition varied among the test plant species. The seedling emergences of all four tested plants were severally inhibited when planted in V. zeylanica contaminated soil. The results indicated that incorporated aqueous leaf extract of V. zeylanica and its rhizosphere contaminated soil can suppress seed germination, seedling growth and seedling emergence of certain plant species indicating a possible allelopathic effect.

Download Full-text

Allelopathic Effect of Artemisia Dubia Extracts on Seed Germination and Seedling Growth of Some Weeds and Winter Crops

Ecoprint An International Journal of Ecology ◽

10.3126/eco.v21i0.11901 ◽

2015 ◽

Vol 21 ◽

pp. 23-30

Author(s):

Baby Babita Das Mallik ◽

BD Acharya ◽

M Saquib ◽

MK Chettri

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Leaf Extract ◽

Cyperus Rotundus ◽

Allelopathic Effect ◽

Ageratum Conyzoides ◽

Bidens Pilosa ◽

Winter Crops ◽

Allelopathic Effects ◽

Artemisia Dubia

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

Download Full-text

Herbicidal Activity of Curvulinic Acid Isolated from Nimbya alternantherae

Natural Product Communications ◽

10.1177/1934578x1200700118 ◽

2012 ◽

Vol 7 (1) ◽

pp. 1934578X1200700

Author(s):

Jun Li ◽

Yonghao Ye ◽

Xiaoyang Wang ◽

Liyao Dong

Keyword(s):

Acetic Acid ◽

Seed Germination ◽

Root Length ◽

Shoot Length ◽

Herbicidal Activity ◽

Phytopathogenic Fungus ◽

Inhibitory Effects ◽

Liquid Cultures ◽

First Time ◽

Phytotoxic Compound

A phytotoxic compound, identified as 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (curvulinic acid), was isolated from liquid cultures of the phytopathogenic fungus Nimbya alternantherae. The activity of curvulinic acid on seed germination and seedling growth of Capsella bursa-pastoris was evaluated. Percentage seed germination of C. bursa-pastoris was decreased with increasing concentrations of curvulinic acid. The compound had stronger inhibitory effects on root length than shoot length. At a concentration of 600 μg·mL−1, curvulinic acid caused 73.5% and 66.7% growth inhibition on roots and shoots with IC50 values of 204.7 and 281.1 μg·mL−1, respectively. The finding of curvulinic acid in N. alternantherae and its herbicidal activity are reported here for the first time.

Download Full-text

Allelopathic Effects of Cinnamomum migao on Seed Germination and Seedling Growth of its Associated Species Liquidambar formosana

Forests ◽

10.3390/f10070535 ◽

2019 ◽

Vol 10 (7) ◽

pp. 535

Author(s):

Deng Wang ◽

Jingzhong Chen ◽

Xue Xiong ◽

Shu Wang ◽

Jiming Liu

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Leaf Extract ◽

Rhizosphere Soil ◽

Starch Accumulation ◽

Soil Extracts ◽

Aqueous Leaf Extract ◽

Allelopathic Effects ◽

High Concentrations ◽

Associated Species

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.

Download Full-text

Response of walnut (Juglans regia L.) leaf aqueous extracts, on seed germination and seedling growth of wheat (Triticum aestivum L.) in agri-silvi system of Uttarakhand

Journal of Applied and Natural Science ◽

10.31018/jans.v5i2.343 ◽

2013 ◽

Vol 5 (2) ◽

pp. 411-415

Author(s):

Abhishek Bahuguna ◽

Sandhya Bahuguna ◽

Birendra Prasad

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Juglans Regia ◽

Wheat Variety ◽

Shoot Length ◽

Dependent Manner ◽

Aqueous Extracts ◽

Leaf Extracts ◽

Concentration Dependent Manner ◽

Root And Shoot Length

Effect of different doses of aqueous extracts of walnut leaf was studied on germinating seeds and early seedling growth of wheat variety (cv. VL-616) recommended for hills under West Himalayan agri-silvi system. Seven treatments comprised of distilled water control (0%), 10%, 20%, 30%, 40%, 50% and 60% concentration of leaf extracts were treated. The effect of aqueous extracts was found inhibitive; indicate a direct proportional relationship with concentration dependent manner on seed germination and subsequent seedling growth of wheat. The wheat variety exhibited extent of phytotoxicity at 60% extracts application in comparison to untreated control. Invariably there was a decrease in first count, germination, seedling root and shoot length, seedling fresh and dry weight and vigour index with increasing aqueous extracts concentration on germinating wheat, however the shoot length was observed maximum at 60% concentration.

Download Full-text

Comparative Allelopathic Effects of Two Weed Extracts on Seed Germination and Seedling Growth of Vigna unguiculata (L.) Walp. and Abelmoschus esculentus L.

Defence Life Science Journal ◽

10.14429/dlsj.5.15653 ◽

2020 ◽

Vol 5 (3) ◽

pp. 204-210

Author(s):

Sanchita Bhattacharya ◽

Shibani Namasudra ◽

Sanjit Debnath ◽

Ajay Krishna Saha

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Vigna Unguiculata ◽

Leaf Extract ◽

Abelmoschus Esculentus ◽

Culture Experiment ◽

Allelopathic Potential ◽

Seedling Length ◽

Stem Extract ◽

Pot Culture

Pot culture experiment and Petri dish bioassay were conducted to assess the allelopathic potential of Cyanthillium cinereum and Lantana camara on seed germination and seedling growth of Vigna unguiculata and Abelmoschus esculentus. Aqueous leaf and stem extracts of weed were used for treatment. The differential inhibitory effect was observed for two weed plants on two tested crops. The experimental results revealed that in case of pot culture experiment, lowest germination percentages (40.8±0.49%, 63.6±0.60% and 83±0.78%) were recorded in L. camara leaf extract treated set of A. esculentus and maximum decrease in seedling length (0.31±0.05 cm, 4.18±0.07 cm, 6.42±0.08 cm and 13.51±0.07 cm) was observed in stem extract treated a set of A. esculentus. L. camara stem and leaf extract induced a more negative effect on seedling length in both A. esculentus and V. unguiculata. For petridish bioassay experiment, lowest germination percentages (54.60±0.40%, 59.20±0.49%, 66.20±0.74% and 69.80±0.38%) were observed in L. camara leaf extract treated a set of A. esculentus. In V. unguiculata, lowest germination percentage (45.8±0.49%, 75.4±0. 40%, 84.4±0.25% and 89±0.32%) was observed in stem extract treated set. Maximum suppressive effect on seedling length was recorded for stem and leaf extract of C. cinereum of A. esculentus and leaf extract of L. camara and stem extract of C. cinereum of V. unguiculata.

Download Full-text

Impact of Intensity and Exposure Duration of Magnetic Field on Seed Germination of Tomato (Lycopersicon esculentum L.)

Notulae Scientia Biologicae ◽

10.15835/nsb417324 ◽

2012 ◽

Vol 4 (1) ◽

pp. 116-120 ◽

Cited By ~ 2

Author(s):

Hassan FEIZI ◽

Hossein SAHABI ◽

Parviz REZVANI MOGHADDAM ◽

Nasser SHAHTAHMASSEBI ◽

Omran GALLEHGIR ◽

...

Keyword(s):

Magnetic Field ◽

Seed Germination ◽

Root Length ◽

Shoot Length ◽

Tomato Seed ◽

Vigor Index ◽

Seedling Length ◽

Mean Germination Time ◽

Experimental Treatments ◽

And Control

In order to study the effect of seed hydro priming and magnetic field on tomato seed germination an experiment was conducted in laboratory of Ferdowsi University of Mashhad, Iran, in 2010. The experimental treatments were all combinations of two levels of hydro priming (use of dry seed and soaked seed for five h in distilled water) and eight levels of magnetic field treatments (pretreatment of seeds in 15 mT for 5, 15 and 25 minutes, pretreatment of seeds in 25 mT for 5, 15 and 25 minutes, continuous magnetic field with 3 mT and control) with four replications. Results indicated that hydro priming of seeds reduced mean germination time significantly. Root length increased by 14 percent in seed hydro priming treatment in comparison with dry seed treatment. Shoot length, seedling length and vigor index of hydro primed seeds increased by 7, 12 and 13 percent, respectively compared with dry seeds. Exposure of seeds with 3 mT continuous magnetic field and 25 mT for 5 min increased root length by 29 and 25 percents, respectively in comparison with control. The highest shoot length, seedling length and vigor index were obtained in 3 mT continuous magnetic field and 25 mT for 5 min.

Download Full-text

Allelopathic Interference of Ageratum conyzoides L. against Rice Varieties

Current Agriculture Research Journal ◽

10.12944/carj.8.2.01 ◽

2020 ◽

pp. 69-76

Author(s):

Bhawna Negi ◽

S.S Bargali ◽

Kiran Bargali ◽

Kavita Khatri

Keyword(s):

Seed Germination ◽

Seedling Growth ◽

Leaf Extract ◽

Water Soluble ◽

Allelopathic Effect ◽

Aqueous Extracts ◽

Ageratum Conyzoides ◽

Leaf Extracts ◽

Rice Varieties ◽

Seedling Length

Ageratum conyzoides L. is an invasive weed that has severely infested cultivated lands and interferes with the growth of crops. In this study aqueous extracts of 50 and 100% concentration were prepared from fresh and air dried plant parts (Leaves and roots) of A. conyzoides and their allelopathic effect was observed on seed germination and seedling growth of two rice varieties namely Sava and Geru. In Sava variety, a significant reduction in seed germination, seedling length and dry weight was recorded under dry leaf extract while under fresh leaf extract seed germination and seedling length was increased at 50% concentration as compared to control. In Geru variety both fresh and dry leaf extracts resulted in decreased seed germination and seedling growth with increasing concentration. Similar patterns were recorded for fresh and dry root extracts. The inhibitory effect of leaf extracts was more pronounced than root extract and overall dry aqueous extracts of leaf and root were more inhibitory than fresh aqueous extracts. Among varieties, Sava was least affected as compared to the Geru. This study indicated that A. conyzoides exert allelopathic effect towards rice crop by releasing water soluble phytochemicals.

Download Full-text