Article

Herbicide activity of volatile oils from Eucalypus citriodora against Parthenium hysterophorus

Annals of Applied Biology

February 2005
146(1):89 - 94

DOI:10.1111/j.1744-7348.2005.04018.x

Authors:

H. P. Singh

Institute of Agricultural Sciences

Daizy Batish

Asian Institute of Technology

Ravinder Kohli

Amity University Punjab Mohali

The herbicidal effect of volatile oils from leaves of Eucalyptus citriodora against the noxious weed Parthenium hysterophorus was tested. In a laboratory bioassay, seed germination and seedling length, chlorophyll content and respiratory activity of Parthenium decreased with increased concentration of eucalypt oils from 0.2 to 5.0 nL mL-1. Germination was completely inhibited at 5.0 nL mL-1 eucalyptus oils. Further, for 4-week-old plants of Parthenium sprayed with different concentrations of volatile oils, visible damage increased and chlorophyll content and respiratory activity decreased with increased concentration from 0 to 100 μL mL-1, the week after spraying. At concentrations up to 50 μL mL-1, plants showed some recovery over time but plants sprayed with 75 and 100 μL mL-1 died 2 weeks after treatment. Plants sprayed with 50 μL mL-1 and higher concentrations of eucalypt oils were desiccated and wilted in appearance. At concentrations of 5–75 μL mL-1, eucalypt oils caused a rapid electrolyte leakage from the Parthenium plants thereby indicating an effect on membrane integrity. It is concluded that volatile oils from E. citriodora possess weed-suppressing ability and could be used as a potential bioherbicide for future weed management programmes.

Assessing the potential of fedaleh (Echinophora cinerea) essential oils as a natural herbicide for spring-summer crops

Article

Full-text available

Aug 2024

Large quantities of chemical herbicides are used in agroecosystems every year, which not only imposes a significant financial burden on farmers but also leads to environmental pollution. To address this challenge, the present study aimed to replace Treflan with Fedaleh essential oils (EO). Treflan is a commonly used chemical herbicide for spring-summer crops, and Chenopodium album has been chosen as a prevalent and abundant weed in many agricultural ecosystems. Four types of inhibitors, including Treflan herbicide and essential oils extracted from the leaf, stem, and flower of Fedaleh, were used in this experiment. These inhibitors were tested at five different concentrations: 0, 0.5, 1, 2, and 5 μL/mL. Based on GC-MS results, the key compounds found in Fedaleh EO were α-pinene, α-phellandrene, γ-terpinene, linalool, sabinol, β-myrcene, neric acid, carvacrol, β-phellandrene, thymol, and spathulenol. A dose-dependent increase in hydrogen peroxide, malondialdehyde, electrolyte leakage, and proline content was observed with Fedaleh EO or Treflan. However, a decline in cell viability, germination, radicle length, radicle weight, plumule length, plumule weight, and seedling vigor index was observed in a dose-dependent manner with Fedaleh EO or Treflan. The weight of the radicle and plumule was noticeably decreased by 27 %, 28 %, and 14 %, 19 % respectively when treated with essential oils derived from the stem and flower of the Fedaleh, as compared to Treflan. Interestingly, at concentrations of 5 μL/mL EO, the germination, radicle length, plumule length, and seedling vigor index significantly decreased by 64–72 %, 56-56 %, 41–44 % and 90–93 % % as compared with control, respectively. The essential oils extracted from different parts of Fedaleh showed no significant difference in terms of hydrogen peroxide, electrolyte leakage, cell viability, and proline content, compared to Treflan (P > 0.05). Compared to the control, Treflan did not affect germination (P > 0.05), but the EO of Fedaleh's different parts significantly inhibited germination (P < 0.05). The growth inhibitors at a concentration of ≥1 μL/mL significantly reduced the length of the radicle and plumule in Chenopodium album. Overall, Fedaleh EO has significant potential as a growth inhibitor and oxidative stress inducer to prevent weed interference. This makes it a suitable option for the commercial production of a natural herbicide.

Metabolomic Insights into the Allelopathic Effects of Ailanthus altissima (Mill.) Swingle Volatile Organic Compounds on the Germination Process of Bidens pilosa (L.)

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Jan 2025

This study explores the allelopathic effects of volatile organic compounds (VOCs) emitted by the invasive species Ailanthus altissima (Mill.) Swingle on the seed germination of Bidens pilosa. A. altissima is known for releasing allelo-pathic VOCs that suppress the growth of neighbouring plants, contributing to its invasive potential. Methods: To examine these effects, we exposed B. pilosa seeds to varying concentrations of A. altissima VOCs, assessing germination rates and metabolic changes through untargeted metabolomics. Results: Our findings revealed that VOCs from A. altissima significantly inhibited the germination speed and overall germination rates of B. pilosa in a dose-dependent manner. Metabolomic profiling showed disruptions in energy and amino acid metabolism pathways, specifically involving delayed breakdown of starch and key metabolites, indicating inhibition of critical metabolic processes during early germination stages. This metabolic delay likely impairs B. pilosa's establishment and competitiveness, enhancing A. altissima's ecological dominance. Conclusions: The results underscore the potential of VOC-based allelopathy as a mechanism of plant invasion, offering insights into the role of VOCs in interspecies plant competition and ecosystem dynamics.

Actividad alelopática de extractos acuosos de especies arbóreas sobre la germinación y crecimiento inicial de dos malezasAllelopathic activity of aqueous extracts of arboreal species on the germination and initial growth of two weeds

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En la búsqueda de opciones sostenibles de manejo de las arvenses Convolvulus arvensis L. y Portulaca oleracea L., se evaluó in vitro el potencial de inhibición de germinación y crecimiento inicial del extracto acuoso de fruto, hoja y corteza de las especies arbóreas, con características alelopáticas, Eucalyptus globulus Labill. y Schinus terebinthifolius Raddi. La inhibición de germinación y crecimiento se evaluó al exponer semillas de las arvenses, dispuestas dentro de una caja Petri, a la aspersión del extracto a diferentes concentraciones. Los extractos de fruto y hoja de S. terebinthifolius, así como el de hoja de E. globulus, inhibieron la germinación y crecimiento de ambas malezas a partir del formulado al 2.5 %. La actividad biológica de los extractos se relacionó positivamente con la concentración. Los resultados sugieren que los extractos de las arbóreas representan una herramienta útil en el manejo agroecológico de las dos arvenses.

Bioactive potential of Mentha arvensis L. essential oil

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Chemical composition and biological activities of essential oils and extract of Eucalyptus citriodora Hook

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Apr 2024

In this study, the leaves of Eucalyptus citriodora Hook (Lemon-Scented Eucalyptus) were harvested and collected from Üzümlü neighborhood of Fethiye district of Muğla in 2021. Chemical content analysis of steam distillation and hydrodistillation of essential oils were determined by GC-MS, while phenolic content of methanol extract was determined by HPLC-DAD. Antioxidant activities of essential oils and methanol extracts were determined by DPPH radical removal, ABTS cation removal, β-carotene linoleic acid, and CUPRAC activity methods; Anticholinesterase activity against AChE and BChE enzymes was determined by Ellman method; and tyrosinase inhibition associated with melanin hyperpigmentation, α-amylase inhibition, and α-glucosidase inhibition activities associated with diabetes were determined as an in vitro. The bioactivities and chemical contents of E. citriodora species, a great value of, Türkiye, were determined, bringing new natural products to organic chemistry. As a result of the study, new bioactive extracts would be obtained and thus, they can effectively reveal the potential of new business opportunities. Since methanol extract is effective against incurable diseases such as Alzheimer's and diabetes, it will also be possible to develop therapeutics of such diseases by investigating the advanced chemistry and in vivo activities of the extracts with new projects.

Antimicrobial, Herbicidal and Pesticidal Potential of Tunisian Eucalyptus Species: Chemoprofiling and Biological Evaluation.

Article

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Apr 2024

The Eucalyptus genus, characterized by its imposing stature and fragrant foliage, has been a source of fascination for humanity over the centuries. The focus of the present investigation was directed towards the essentials oils (EOs) of five Eucalyptus trees cultivated in Tunisia. The GC-MS analysis unveiled unique compositional profiles, a finding substantiated by both Hierarchical Clustering Analysis (HCA) and Principal Component Analysis (PCA) conducted on the leaves EOs. These analyses resulted in the formation of discrete HCA clades, delineating 23 significant components. Notably, the percentage of eucalyptol emerged as the pivotal factor demarcating the separation between three distinct groups. The statistical analysis revealed a dose-dependent relationship in both phytotoxicity evaluation and antibacterial activity. The EOs from Eucalyptus loxophleba and E. salubris exhibited the highest phytotoxicity, inhibiting radical elongation and germination of various seeds, especially Sinapis arvensis and Raphanus sativus. The antimicrobial assessment demonstrated significant inhibitory effects of the EOs on bacterial strains, with MIC values spanning from 14 to exceeding 50 mg/ml. The EOs also affected biofilm formation and cellular metabolism, displaying varied efficacy among different Eucalyptus species against some bacterial strains. The EOs exhibited selective inhibition against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, and α-glucosidase. E. campaspe EO showed the highest AChE activity, while E. loxophleba and E. salubris EOs were most potent toward α-amylase. E. loxophleba EO demonstrated notable activity against α-glucosidase. Overall, these findings provide important data about the diverse biological activities of Eucalyptus EOs, suggesting potential applications in agriculture, medicine, and pharmacy.

Growing Eucalypt Outside its Native Range: A Review on Suitability and Beneficial Role

Article

Full-text available

Jan 2024

Eucalypt is an industrial short rotation fast growing tree species (SRFGTs), having wide range regarding climatic and edaphic requirements in Indian subcontinent. Eucalyptus camaeldulensis, E. globulus, E. grandis, E. tereticornis and E. citriodora are the widely planted eucalyptus species for different purposes in the country. Oil extracted from E. globulus has medicinal value and used to inhibit the avian influenza virus H11N9, and has wide scope in cosmetics, perfume, food, beverages, phytotherapy and aromatherapy. Oil contain p-coumaric, gallic, gentisic, p-hydroxybenzoic, syringic and vanillic acids and catechol are the responsible for retarding seed germination growth and survival of Parthenium, Solanum lycopersicum, Lactuca sativa and Agrostis stolonifera. Burning of eucalypt leaves used as mosquito repellent and compound 1, 8 cineole of eucalypt oil damage and kills Pediculus humanus capitis and lice. Aqueous solutions extracted from different parts of eucalypt showed nematocidal properties. Maize, wheat, mustard, berseem, potato, lentil are agricultural crops widely grown under eucalypt based agroforestry systems. Wider spacing of eucalypt in block plantations or boundary plantation mostly adopted in the agroforestry systems. Eucalypt sequester carbon 6 – 43 Mg C ha-1 yr-1 under plantations and agroforestry systems. The species has potential to reclaim waterlogged sites and escalate soil health through improving soil physical, chemical and biological properties. In case of economic returns from eucalypt based agroforestry systems, it gives nearly 1.5 B:C ratio.

Allelopathic weed management in wheat (Triticum aestivum L.) through essential oil emulsions and aqueous botanical extracts-based novel bioherbicides

Article

Feb 2024

Phytotoxic activity of essential oil emulsions (EOEs) of aromatic plants such as Mentha piperita, Pelargonium graveolens, Matricaria chamomilla, Chrysopogon zizanioides, Pogostemon patchouli, Mentha arvensis, and aqueous extracts of Andrographis paniculata were evaluated for problematic weeds like Avena fatua and Phalaris minor, along with wheat (Triticum aestivum) as a test crop through laboratory bioassay studies during 2020–2021. The chemical composition of essential oils was analyzed through GC/GC–MS. Results of the laboratory bioassay revealed that EOEs of M. piperita, C. zizanioides, M. arvensis, and an aqueous extract of A. paniculata as pre-emergence bioherbicides strongly inhibited germination and seedling growth of the tested weed species in a dose dependent manner, with P. minor and A. fatua being selectively more sensitive than T. aestivum. Percent seed germination varied between treatments, ranging from 3.45–48.28%, 3.45–100%, and 4.55–90.91% among T. aestivum, A. fatua, and P. minor, respectively. Based on these results, these four treatments showing the highest phytotoxic activity were further evaluated through a pot culture study. The results showed that treatments with essential oil emulsions and aqueous extracts had a negative impact on seedling Vigor Index I and Vigor Index II. Comparing physiological processes in P. minor, like relative electrolyte leakages, essential oil of M. arvensis at concentration 1% + 8% (pre emergence + early post emergence) had the highest levels of 47.16%, followed by the value of 38.86% which was recorded in C. zizanioides at concentration 1% + 8% (pre emergence + early post emergence) and 22.80% reported in M. piperita at concentration 1% + 8% (pre emergence + early post emergence) treated plants. These levels were higher than those in the untreated control (10.13%). Indeed, at higher concentrations of each treatment, grain yield per plant decreased in the range of 7–29% with respect to the untreated control. The data on phytotoxicity rating showed that visible injury symptoms in T. aestivum plants were less severe as compared to the symptoms recorded in A. fatua and P. minor weeds. This is the first in-depth study to show that emulsions of essential oils from P. graveolens, C. zizanioides, and P. patchouli are phytotoxic. It is also the first time that M. arvensis and C. zizanioides have been shown to be pre-emergence bioherbicides in wheat. Hence, our study presents these EOEs as novel candidates of biological origin that can be used in sustainable weed management, especially in organic farming systems.

Chemical Analysis and Bioactivities of Gaultheria procumbens L. Essential Oil: Herbicidal, Antioxidant and Antibacterial Activities

Article

Full-text available

Feb 2023

The chemical composition of wintergreen (Gaultheria procumbens L.) essential oil (WEO) was identified by gas chromatography-mass spectrometry (GC-MS) and evaluated for its biological activities. Methyl salicylate (100%) was the main compound in the wintergreen essential oil. The herbicidal efficacy of the WEO was confirmed by germination inhibition, radical and shoot length reduction, and phytotoxicity assessment with Echinochloa crus-galli and Amaranthus tricolor seedlings. The WEO significantly reduced the germination and seedling growth of both weeds. It showed highly significant inhibition of seed germination (93.37%) and seedling growth of A. tricolor at the highest dose (6 µL/petri dish) assayed. The WEO was formulated as an emulsifiable concentrate (EC-EO) for post-emergence application, and was applied at a range of concentrations from 10 to 80 mL/L. Both treated plant leaves appeared wilted and slightly discolored within 1 day of application (DAA). The visible weed control efficacy was most remarkable at 80 mL/L treatment, which was a level that ultimately killed the seedlings of both species at 3 DAA, suggesting promising herbicidal potential for the WEO. The WEO showed weak scavenging activity with a high IC50 value (IC50 >2×10 4 and >5×10 4 ppm) for DPPH scavenging and metal chelating assays, respectively. The WEO showed moderate antibacterial activity, and its zones of inhibition against bacterial test strains were 7.90±0.8 mm and 23.9±0.9 mm for Escherichia coli TISTR 780 and Staphylococcus aureus TISTR 1466, respectively. Therefore, the results suggest the possibility of using WEO as an active ingredient to produce natural herbicides. Keywords essential oil; EC-EO; Gaultheria procumbens; bioactivity; herbicidal activity; antibacterial activity; antioxidant activity Curr. Appl. Sci. Technol. Vol. 23 No. 5 S. Jintanasirinurak et al. 2

Parthenium hysterophorus L.: An Overview of Management and Beneficial Aspects

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Dec 2023

The poisonous and invasive weed Parthenium hysterophorus L., also referred to as "famine weed" or "congress grass," is highly dangerous for human health, agriculture, and biodiversity. This plant is well known for its aggressive growth and allelopathic qualities, which prevent natural vegetation and good crops from growing. An overview of the benefits and treatment of Parthenium hysterophorus is given in this abstract. Many techniques, including mechanical removal, chemical herbicides, biological control agents, and cultural practices, are used to combat this weed. To successfully control its spread, integrated techniques are frequently advised. Parthenium hysterophorus has drawbacks, yet it also has some positive qualities. It has therapeutic qualities, and research indicates that it may be used in phytoremediation and the synthesis of biofuel. The main goal is to draw attention to how critical it is to manage Parthenium hysterophorus properly while investigating its possible benefits, underscoring the necessity of long-term, all-encompassing solutions to deal with this environmental threat.

Agronomic and nutritional evaluation of Groundnut crop as affected by moringa leaf extract and zinc application

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Mar 2024

Current study was conducted to exploit the potential of zinc and moringa leaf extract for improving the growth and yield of groundnut at Attock, Pakistan. The study was laid out in RCBD two factor factorial arrangements having four replications. Plot size was 7.2 m 2. All agronomic practices were carried out uniformly in all treatments throughout the study. The treatment detail is as: Factor-A; Levels of MLE (Percentage %) M1 = 0%, M2 = 10%, M3 = 20%, M4 = 30%, M5 = 40%, Factor-B; Zinc doses (Kg/ha), Z1 = 0 kgha-1 , Z2 = 3 kgha-1 , Z3 = 6 kgha-1 , Z4 = 9 kgha-1 , Z5 = 12 kgha-1. Groundnut variety Attock-2019 was sown at a spacing of 20 cm and 70cm apart. Seed rate of 25 kg ha-1 was used. Results revealed that maximum Plant height (42.6 cm), number of branches plant-1 (9.13), crop growth rate (20.4 g m-2 d-1), chlorophyll content (0.68 mgg-1), pods plant-1 (66.6), 100 seed weight (77.8 g), total free amino acids (383) and total phenolic content (88.5) were significantly affected by foliar application of moringa leaf extract at the rate of 20% along with zinc at the rate of 12 kgha-1. It is concluded that the growth, yield, and nutritional contents of groundnut are positively affected by the combination of higher dose of zinc @ 12 kgha-1 and moringa leaf extract @ of 20%.

Allelopathic Effect of Aqueous Leaf Extract of Parthenium hysterophorus L. on Seed Germination and Seedling Growth in Greengram, Blackgram and Groundnut

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Allelopathic effect of Parthenium hysterophorus L. was studied on seed germination and seedling growth of two pulse crops (Vigna radiata (L.) R. Wilczek and Vigna mungo (L.) Hepper) and one oil seed crop (Arachis hypogea L.). The concentrations used were 20 g L -1 , 30 g L -1 and 50 g L -1 leaf extract of Parthenium hysterophorus. Seed germination of greengram was completely inhibited at 30 g L -1 leaf extract of Parthenium hysterophorus but in blackgram and ground nut, failure of seed germination was recorded only at 50 g L-1 leaf extract. The seed germination, plumule, radicle length and total biomass production were reduced with increasing concentration of aqueous solution. The study concluded that increasing concentration of leaf extract of Parthenium hysterophorus has adverse effect on germination, radicle length, plumule length and biomass production of Vigna radiata followed by Vigna mungo and Arachis hypogea than the control. The leaf extract has strong inhibitory effect on radicle growth than the plumule growth. The tolerance level of parthenium allelopathy of crops represented as Groundnut > Blackgram > Greengram.

Chemical Composition of Essential Oils from Eight Tunisian Eucalyptus Species and Their Antifungal and Herbicidal Activities

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Aug 2023

Eucalyptus species are known to produce metabolites such as essential oils (EOs) that play an important role in the control of weeds, pests and phytopathogenic fungi. The aims of this study were as follows: (i) to determine the chemical composition of the EOs derived from eight Eucalyptus species growing in Tunisia, and (ii) to study their possible antifungal and herbicidal activities. EOs were obtained by hydrodistillation from the dried leaves of eight Eucalyptus species, namely, E. angulosa, E. cladocalyx, E. diversicolor, E. microcoryx, E. ovata, E. resinifera, E. saligna and E. sargentii, and the determination of their composition was achieved by GC and GC-MS. The EOs’ antifungal activities were tested against four Fusarium strains, and the EOs’ herbicidal properties were evaluated on the germination and seedling growth of three annual weeds (Trifolium campestre, Lolium rigidum and Sinapis arvensis) and three cultivated crop species (Lepidium sativum, Raphanus sativus and Triticum durum). The EO yields ranged between 0.12 and 1.32%. The most abundant components found were eucalyptol, α-pinene, p-cymene, trans-pinocarveol, α-terpineol and globulol. All EOs showed significant antifungal activity against the four phytopathogenic Fusarium strains. E. cladocalyx EO exhibited the highest level of antifungal activity, and the greatest inhibition of seed germination was obtained even at lowest concentrations used. These findings suggested that E. resinifera, E. ovata and E. cladocalyx EOs could have applications in agriculture as possible biopesticides, as Fusarium antagonists and as bioherbicides.

Chemical composition, antioxidant, herbicidal and antifungal activities of leaf essential oils from three Tunisian Eucalyptus species

Article

Full-text available

Jun 2023
Z PFLANZENK PFLANZEN

Medicinal plants produce several natural bioactive molecules and compounds called secondary metabolites that have very important biological properties. The objective of this work is to determine the chemical composition of essential oils (EO) obtained from the leaves of three Tunisian species of Eucalyptus (E. oleosa, E. pimpiniana, E. polyanthemos) and to evaluate their biological activities. As a result, 45 different compounds were identified: 26 from E. pimpiniana, 15 from E. polyanthe-mos, and 39 from E. oleosa, which represent 99.4%, 99.4% and 98.6%, respectively, of the entire essential oil constituents. The analyses showed that 1,8-cineole (35.3%) and β-eudesmol (25.5%) were the main components in E. pimpiniana essential oil, whereas 1,8-cineole (71.6%) and globulol (13.2%) characterized E. polyanthemos leaf oil. Also, 1,8-cineole (13.4%), spathulenol (11.9%), and β-eudesmol (8.5%) were found to be the main constituents of E. oleosa EO. Other compounds, such as phellandral, p-cymen-7-ol (syn. cumin alcohol), carvacrol, myrtenal, cumin aldehyde and cryptone, are specific to the EOs of E. oleosa, making it distinct from the other Eucalyptus species studied. The essential oils showed low antioxidant capacity, but significant antifungal activity against five Fusarium spp. Indeed, E. oleosa essential oil exhibited the highest level of antifungal activity. Additionally, herbicidal activity has only been proved in a preliminary in vitro test against 3 weed species (Sinapis arvensis L., and Lepidium sativum) of the same family. The greatest inhibition of seed germination was obtained with the E. oleosa essential oils even at low concentrations strongly suggesting that they could have application in agriculture, particularly as antagonists against Fusarium and other fungi and for weed control.

Review of the Current Research Progress of Seed Germination Inhibitors

Article

Full-text available

Apr 2023

Germination inhibitors, which inhibit the germination of seeds, spores and other plant reproductive material, are abundant in the plant kingdom and include phenols, cyanides, alkaloids, essential oils, amino acids, etc. These inhibitors can be classified as germination destructors and germination retarders depending on whether they harm the morphology, structure and physiology of the seed. Germination retarders are closely related to seed dormancy, and exogenous retarders can be used to extend the “dormancy” period of non-dormant seeds or perishable seeds by applying the proper dosage. They have significant potential applications as preservatives for seed preservation following harvest or for the storage of long-term germplasm resources. Germination destructors, as a type of relatively high-efficiency, low-specificity “toxic chemicals”, are of significant benefit in the application of effective and environmentally benign herbicides. At present, the main problems related to the research methods of germination inhibitors include difficulty in determining the specific endogenous substances and the minimum inhibitory concentration to induce dormancy, as well as whether the application of exogenous inhibitors will cause physiological damage to seeds. In the future, we should strengthen the tracking of germination inhibitors, explore the mechanisms of action of specific substances and deeper molecular mechanisms and finally explore new developments and new applications of different inhibitors.

Citronellol Disrupts Membrane Integrity by Inducing Free Radical Generation

Article

Full-text available

Jun 2014
Z NATURFORSCH C

Citronellol, an oxygenated monoterpene, is found naturally in the essential oils of several aromatic plants and has been reported to exhibit growth inhibitory and pesticidal activities. However, its mechanism of action is largely unexplored. We investigated the effect of citronellol, which is lipophilic in nature on membrane integrity in terms of lipid peroxidation, conjugated dienes content, membrane permeability, cell death, and activity of the enzyme lipoxygenase in roots of hydroponically grown wheat. Citronellol (50 - 250 μM) caused a significant inhibition of root and shoot growth. Furthermore, exposure to citronellol enhanced the solute leakage, increased the malondialdehyde content and lipoxygenase activity, and decreased the conjugated diene content. This indicates that citronellol induces generation of reactive oxygen species (ROS) resulting in lipid peroxidation and membrane damage. This was confirmed by in situ histochemical studies indicating cell death and disruption of membrane integrity. We conclude from this study that citronellol inhibits the root growth by ROS-mediated membrane disruption.

Inhibitory Effect of Oregano and Laurel Essential Oils and Their Main Com-ponents on Seed Germination of Some Weed and Crop Species

Article

Full-text available

Aug 2022

The essential oils from oregano (Origanum syriacum L.) and laurel (Laurus nobilis L.), and their main components, namely, carvacrol, 1,8-cineole and α-pinene, were tested to determine their inhibitory effects on the seed germinations of three different weeds [redroot amaranth (Amaranthus retroflexus L.), wild licorice (Glycyrrhiza glabra L.), curled dock (Rumex crispus L.) and cutleaf ground-cherry (Physalis angulata L.)] and three crops [(wheat (Triticum aestivum L.), corn (Zea mays L.) and cotton (Gossypium hirsitum L.)]. Gas chromatography/mass spectroscopy (GC-MS) analysis showed that 1,8-cineole and carvacrol were the major components of laurel and oregano essential oils, respectively. An in-vitro bioassay seed germination test showed that oregano essential oil and carvacrol completely inhibited the germination of weeds at all the concentrations ranging from 1 to 5 µl/Petri dish, while seed germination of test weeds significantly decreased with increasing of the concentrations of laurel essential oil and its main components, 1,8-cineol and α-pinene ranging from 5 to 20 µl/Petri dish. Oregano essential oil and carvacrol were totally ineffective on cotton and corn germination (except for the concentration of 5 µl/Petri dish of cavracrol), whereas they had a strong inhibitory activity against wheat seeds. On the other hand, the laurel essential oil and its main component, 1,8-cineole, showed less selective action on test crop species. It could be concluded that volatile oil from O. syriacum and its main component, cavracrol, possessed a strong inhibitory effect on germination of the weeds and was totally selective action on some crops, and could be utilized as bioherbicide for future weed management programmes.

Achievements, Developments and Future Challenges in the Field of Bioherbicides for Weed Control: A Global Review

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Full-text available

Aug 2022

The intrusion of weeds into fertile areas has resulted in significant global economic and environmental impacts on agricultural production systems and native ecosystems, hence without ongoing and repeated management actions, the maintenance or restoration of these systems will become increasingly challenging. The establishment of herbicide resistance in many species and unwanted pollution caused by synthetic herbicides has ushered in the need for alternative, eco-friendly sustainable management strategies, such as the use of bioherbicides. Of the array of bioherbicides currently available, the most successful products appear to be sourced from fungi (mycoherbicides), with at least 16 products being developed for commercial use globally. Over the last few decades, bioherbicides sourced from bacteria and plant extracts (such as allelochemicals and essential oils), together with viruses, have also shown marked success in controlling various weeds. Despite this encouraging trend, ongoing research is still required for these compounds to be economically viable and successful in the long term. It is apparent that more focused research is required for (i) the improvement of the commercialisation processes, including the cost-effectiveness and scale of production of these materials; (ii) the discovery of new production sources, such as bacteria, fungi, plants or viruses and (iii) the understanding of the environmental influence on the efficacy of these compounds, such as atmospheric CO2, humidity, soil water stress, temperature and UV radiation.

Allelopathic effects of sunflower water extract integrated with affinity herbicide on weed control and wheat yield

Article

Full-text available

Jul 2022

The aim of present study was to investigate the allelopathic impact of sunflower water extract integrated with affinity herbicide on weed management and production of wheat variety TD-1 under field condition. The trial was carried out in a three replicated and the average plot size was kept at 3x5m (15 m2). The obtained data showed that the all the treatments considerably (P<0.05) minimized weed density, weed fresh weight, weed dry weight and weed control up to 90.33, 89.31, 89.61, 90.33% with application of sunflower water extract (1:10) @ 20 L ha-1 (One spray at 25 DAS) + Affinity 50 WP @ 0.75 kg ha-1 (One spray at 25 DAS) than control treatment. The application of sunflower water extract (1:10) @ 20 L ha-1 (One spray at 25 DAS) + Affinity 50 WP @ 0.75 kg ha-1 (One spray at 25 DAS) significantly increased number of tillers (32.34%), plant height (14.59%), spike length (27.89%), grains spike-1 (16.80%), grain weight plant-1 (47%), seed index (19.60%) and grain yield (51%) of wheat as compared with control. Overall results indicated that the sunflower water extract integrated with herbicide can be successfully used to control the narrow and broad leaves in wheat crop.

Structural Diversity of Complex Phloroglucinol Derivatives from Eucalyptus Species

Article

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Several species of the genus Eucalyptus are used in many traditional medicine systems for the treatment of respiratory tract infections, colds, flu, sore throats, and bronchitis. The genus Eucalyptus (Myrtaceae) is a well‐known natural source of bioactive phloroglucinols. These polyphenolic compounds bear an aromatic phenyl ring with three hydroxy groups (1,3,5‐trihydroxybenzene) which have been exhibiting a variety of biological activities such as antimicrobial, anticancer, anti‐allergic, anti‐inflammatory, and antioxidant activities. This review summarizes the literature published from 1997 until the end of 2021 and addresses the structure diversity of phloroglucinols isolated from Eucalyptus species and their biological activities. Phloroglucinol‐terpene adducts are the main class of compounds that have been reported in this genus.

Improvement the Drought Tolerance of Eucalyptus citriodora Seedling by Spraying Basil Leaves Extract and Its Influence on Growth, Volatile Oil Components and Some Enzymatic Activity

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Full-text available

Apr 2022

Abstract The pot experiment was conducted in Horticulture Research Institute (HRI), Agricultural Research Center, Giza, Egypt during two successive seasons of 2020 and 2021 to study the effect of basil leaves extract (BLE) on growth, chemical composition and different properties for essential oil of Eucalyptus citriodora seedlings under different irrigation intervals. Results clarified that the vegetative growth parameters and photosynthetic pigments were increased in plants that were irrigated every 6 days but proline and MDA were decreased at the same treatment. While, leaf area showed high increment in plants irrigated every 4 days, whereas, all root traits, total sugars content in all organs and antioxidant enzymes activity (PPO, SOD, POD and CAT) were raised by irrigation intervals every 8 days. E. citriodora plants sprayed with BLE at rate 20% produced the highest value for all vegetative growth parameters and all chemical compositions except proline and MDA which showed the lowest value at the same rate. Irrigation every 6 or 8 days with spraying 20 or 40 % of BLE was the best treatments for production of essential oil fresh leaves. Main constituent of essential oil of Eucalyptus citriodora fresh leaves is citronellal which reached to 71.54% by irrigation every 8 days with spraying 40% of BLE, the oil was monoterpenoid 92.59- 97.93%. Oil and its major monoterpenes exhibited restrained to strong antioxidant activity.

Allelopathic potential of Annona muricata (L.) on physiological and biochemical changes of Vigna radiata (L.) and Eleusine coracana (L.) Gaertn

Article

Full-text available

Apr 2022

An experiment was conducted to assess the allelopathic potential of leaf extract of Annona muricata (L.) on physiological and biochemical changes of Vigna radiata (L.) and Eleusine coracana (L.) Gaertn. Annona muricata inhibits and stimulates other plants’ growth, a phenomenon called “allelopathic effect.” Crude water extract of the leaves of A. muricata was treated on V. radiata and E. coracana in different concentrations such as 1%, 2%, 3%, 4%, and 5%, respectively. A control crop was treated with distilled water. The morphological and physiological effects on V. radiata and E. coracana were observed and recorded. Data were recorded on seed germination (after 10 days of seed sowing), growth, and biochemical composition (15 days old seedlings). Reduction in germination percentage of V. radiata and E. coracana was recorded using leaf extract of A. muricata. The outcome of this research work showed that the extracts from the leaves of the A. muricata plant inhibit and stimulate the growth and development of the test seedlings. The biochemical constituents of test seedlings, such as chl a, chl b, carotenoid, protein, amino acid, carbohydrate, peroxidase, and catalase were observed. The extracts were absorbed through the roots of these plants, affecting physiological processes such as photosynthetic and transpiratory rates, stomatal closure, and reduced chlorophyll content, resulting in wilting, tissue maceration, and stunted growth. Between the two crops, more allelopathic effect was recorded in E. coracana. These results showed that there are differences in allelopathic inhibition and stimulation of crops.

http://dx.doi.org/10.22377/ajp.v14i2.3608

Article

Full-text available

Mar 2020

Parthenium plant, in general, is known to be harmful, dangerous, and invasive in nature. It causes much economic loss to farmers by affecting the cultivation of crops and considered to be a threat to primary production of crops and biodiversity as well. Parthenium hysterophorus a weed belonging to the family Asteraceae, it is an erect short-lived plant and is known for its fleshy growth along sides of abandoned places, roadsides, and uncultivated lands. This weed is found in hot and humid climates around the globe. This invasive species is known with different names in different countries such as carrot weed, star weed, congress grass, wild feverfew, ragweed, bitter weed, and white top. The spread of P. hysterophorus has been found to cause enormous loss to biodiversity by replacing natural ecosystems and sometimes known to cause total habit alternation. In this review article, we discuss P. hysterophorus as a weed, its origin, reproductive bionomics, chemical composition, and its pharmaceutical potential as antibacterial, anti-inflammatory, hypoglycemic, anti-HIV, and antitumor activity in detail.

Phytotoxic effects of essential oils from Nepeta glocephalata Rech.f. and N. ispahanica Boiss. on se-lected weed species

Article

Full-text available

Dec 2021

p class="042abstractstekst">In the present study the bioherbicidal activity of essential oils hydrodistilled from Nepeta glocephalata Rech.f and N . ispahanica Boiss were investigated on four weed species (barnyard grass ( Echinochloa crus-galli (L.) Beauv), redroot pigweed ( Amaranthus retroflexus L.), lambsquarters ( Chenopodium album L.) and canary grass ( Phalaris canariensis L.)). A total of 37 components were identified from the essential oils of N. glocephalata and N. ispahanica constituting approximately 98.61 % and 96.1 % of the oils, respectively. In laboratory bioassay different concentrations (0, 1, 2, 4 and 8 μl ml^-1) of two Nepeta essential oils on germination, root and shoot length were studied. Results showed by increasing the concentration of oils, all studied traits of the weeds were decreased compared with control. In a glass house bioassay post-emergence application of Nepeta essential oils (1.25 %, 2.5 %, 5 % and 10 %, v/v) on 3-week-old weed plants caused visible injury (7-days after spray) ranging from chlorosis to necrosis of plant weeds. In foliar application under glasshouse conditions, both Nepeta essential oils reduced the seedling dry mass and concentrations of chlorophyll a chlorophyll b. The study concludes that Nepeta essential oils have phytotoxic effects and could be used as bioherbicides but the selectivity of these compounds should be considered also.</p

Exploring the potential of moringa leaf extract as bio stimulant for improving yield and quality of black cumin oil

Article

Full-text available

Dec 2021

The history of plants to be utilized as medicines is thousands of years old. Black cumin is one of the most widely examined plant possessing naturally occurring compounds with antimicrobial potential. Foliar application of growth stimulators is a successful strategy to enhance yield and quality in many crops. A field study was planned to apply growth stimulator like moringa leaf extract on black cumin crop grown under field conditions using RCB design with three replications. All other agronomic inputs and practices were uniform. The treatments were moringa leaf extract concentrations (10%, 20%), growth stages (40 days after sowing, 80 DAS, 120 DAS, 40 + 80 DAS, 40 + 120 DAS, 80 + 120 DAS, 40 + 80 + 120 days after sowing) and two controls unsprayed check (i.e. no moringa leaf extract, no water) and sprayed check (no moringa leaf extract + water). Application of 20% moringa leaf extract at stage-7 (40 + 80 + 120 days after sowing) had significantly increased plant height, branches plant ⁻¹ , essential oil content, fixed oil content, peroxidase value and iodine value of black cumin oil over unsprayed control. Application of moringa leaf extract showed maximum results and improves growth and yield of black cumin when applied at 40 + 80 + 120 days after sowing. As this study was only conducted using moringa leaf extract, it is advisable to conduct an experiment with various bio stimulants along with fertilizer combinations and growth regulators to check their synergistic effects for more reliable and acceptable recommendations in future.

Microencapsulation in the formulation of agricultural inputs for sustainable agriculture

Chapter

Feb 2021

Pest management in agriculture is badly needed because approximately one third of the world’s potential food supplies are lost to pests and diseases, and these losses would rise if crop protection were not implemented. In the last 40 years, the massive increase in the use of synthetic pesticides made it possible to increase food production. However, its excessive use is currently causing negative effects on health and the environment, as well as a rapid emergence of resistance in the pests. Growing social awareness about the impact of agricultural practices has also contributed to promoting the development of safer formulations for the advancement of sustainable agriculture. In recent years, there has been a greater interest in the use of alternative control strategies for the management of pests in crops, including the use of natural substances of plant origin such as essential oils, with the intention of introducing inputs eco-friendly farming. However, its application in agriculture usually faces some limitations. Essential oils present as limitations in their field application the stability and persistence of their effects over time. This chapter presents an overview of the use of essential oils to control phytopathogens and weeds in agricultural systems and different microencapsulation strategies that scientists implemented in order to avoid the disadvantages of applying pure oils. Therefore, the purpose of this review is to compile updated information on the innovative methods used for the development of formulations of the bio-pesticide based on essential oils reported in the scientific literature. The use of the formulations against phytopathogenic fungi, bacteria, insects, phytoparasitic nematodes and weeds are being investigated as alternatives to synthetic pesticides for the development of a more sustainable agriculture. Research trends are moving towards the development of greener agricultural formulations. The formulation of control agents using microencapsulation techniques improves their stability and biological activity, and therefore would allow their application on a larger scale, thus representing an innovative method for these products to be positioned on the market.

Extracts of Euphorbia nivulia Buch.-Ham. showed both phytotoxic and insecticidal capacities against Lemna minor L. and Oxycarenus hyalinipennis Costa

Article

Full-text available

Apr 2021
PLOS ONE

Many phytochemicals can affect the growth and development of plants and insects which can be used as biological control agents. In this study, different concentrations of crude, hexane, chloroform, butanol, and aqueous extracts of Euphorbia nivulia Buch.-Ham., an endemic plant of the Cholistan desert in South Punjab of Pakistan, were analysed for their chemical constituents. Their various concentrations were also tested for their phytotoxic and insecticidal potential against duckweed, Lemna minor L., and the dusky cotton bug, Oxycarenus hyalinipennis Costa. various polyphenols, i.e., quercetin, gallic acid, caffeic acid, syringic acid, coumaric acid, ferulic acid, and cinnamic acid were detected in different concentrations with different solvents during the phytochemical screening of E. nivulia. In the phytotoxicity test, except for 100 μg/mL of the butanol extract gave 4.5% growth regulation, no phytotoxic lethality could be found at 10 and 100 μg/mL of all the extracts. The highest concentration, 1000 μg/mL, of the chloroform, crude, and butanol extracts showed 100, 63.1, and 27.1% of growth inhibition in duckweed, respectively. In the insecticidal bioassay, the highest O. hyalinipennis mortalities (87 and 75%) were recorded at 15% concentration of the chloroform and butanol extracts of E. nivulia. In contrast, the lower concentrations of the E. nivulia extracts caused the lower mortalities. Altogether, these findings revealed that E. nivulia chloroform extracts showed significant phytotoxicity while all the extracts showed insecticidal potential. This potential can be, further, refined to be developed for bio-control agents.

Sugarcane varietal response for sucrose accumulation subjected to thermal stress at formative stage

Article

Full-text available

Apr 2022

Unraveling Sorghum Allelopathy in Agriculture: Concepts and Implications

Article

Full-text available

Aug 2021

Allelopathy is an ecological phenomenon that involves the production and release of biomolecules from different crops, cultivated plants, and bacteria or fungi into the soil rhizosphere and impacts other organisms in the vicinity. Sorghum possesses vital allelopathic characteristics due to which it produces and releases different biomolecules from its root hairs, stems, and grains. Several studies have reported that sorghum acts as an allelopathic crop, decreasing the growth and eco-physiological attributes of surrounding plants and weeds growing simultaneously or subsequently in the field. Sorghum allelopathy has been exploited in the context of green manure, crop rotations, cover crops, and intercropping or mulching, whereas plant aqueous extracts or powder might be an alternate method of weed control. A diverse group of allelochemicals, including benzoic acid, p-hydroxybenzoic acid, vanillic acid, ferulic acid, chlorogenic acid, m-coumaric acid, p-coumaric acid, gallic acid, caffeic acid, p-hydroxibenzaldehyde, dhurrin, sorgoleone, m-hydroxybenzoic acid and protocatechuic acid, have been isolated and identified from different plant tissues of sorghum and root exudates. These allelochemicals, especially sorgoleone, have been investigated in terms of their mode(s) of action, specific activity and selectivity, release in the rhizosphere and uptake and translocation in sensitive species. The present review describes the importance of sorghum allelopathy as an ecological tool in managing weeds, highlighting the most recent advances in the allelochemicals present in sorghum, their modes of action, and their fate in the ecosystem. Further research should focus on the evaluation and selection of sorghum cultivars with high allelopathic potential, so that sorghum allelopathy can be better utilized for weed control and yield enhancement.

Unraveling Sorghum Allelopathy in Agriculture: Concepts and Implications

Article

Aug 2021

adela@uvigo.es (A.M.S.-M.), mreigosa@uvigo.es (M.J.R.) Abstract: Allelopathy is an ecological phenomenon that involves the production and release of biomolecules from different crops, cultivated plants, and bacteria or fungi into the soil rhizosphere and impacts other organisms in the vicinity. Sorghum possesses vital allelopathic characteristics due to which it produces and releases different biomolecules from its root hairs, stems, and grains. Several studies have reported that sorghum acts as an allelopathic crop, decreasing the growth and eco-physiological attributes of surrounding plants and weeds growing simultaneously or subsequently in the field. Sorghum allelopathy has been exploited in the context of green manure, crop rotations, cover crops, and intercropping or mulching, whereas plant aqueous extracts or powder might be an alternate method of weed control. A diverse group of allelochemicals, including ben-zoic acid, p-hydroxybenzoic acid, vanillic acid, ferulic acid, chlorogenic acid, m-coumaric acid, p-coumaric acid, gallic acid, caffeic acid, p-hydroxibenzaldehyde, dhurrin, sorgoleone, m-hydroxybenzoic acid and protocatechuic acid, have been isolated and identified from different plant tissues of sorghum and root exudates. These allelochemicals, especially sorgoleone, have been investigated in terms of their mode(s) of action, specific activity and selectivity, release in the rhizosphere and uptake and translocation in sensitive species. The present review describes the importance of sorghum allelopathy as an ecological tool in managing weeds, highlighting the most recent advances in the allelochemicals present in sorghum, their modes of action, and their fate in the ecosystem. Further research should focus on the evaluation and selection of sorghum cultivars with high allelopathic potential, so that sorghum allelopathy can be better utilized for weed control and yield enhancement. Citation: Hussain, M.I.; Danish, S.; Sánchez-Moreiras, A.M.; Vicente, O.; Jabran, K.; Chaudhry, U.K.; Branca, F.; Reigosa, M.J. Unraveling Sor-ghum Allelopathy in Agriculture: Concepts and Implications. Plants 2021, 10, 1795. https://doi.

Unraveling Sorghum Allelopathy in Agriculture: Concepts and Implications

Article

Full-text available

Aug 2021

Use of agro-wastes for Lasiodiplodia pseudotheobromae (C1136) production with sustainable bioefficacy

Article

Full-text available

Jun 2022
Environ Dev Sustain

The study was undertaken to prime a strain of Lasiodiplodia pseudotheobromae (C1136) as a mycoherbicidal agent against Amaranthus hybridus L. (pigweed) utilizing various agricultural wastes for its production. The rate of mortality and dry weight reduction of the target weed was determined in both the greenhouse and field conditions. The mycoherbicidal efficacy of the highly virulent isolate (strain C1136) was established based on the influence of the dew period, temperature, and inoculum concentration as well as plant growth stages. A dew period of 72 h was observed to be the highest time period necessary to obtain 90.6% mortality rate while there was no death observed at 0- and 12-h dew period treatments, respectively. Maximum disease development and mortality rate was observed at 25 °C on the target weed. It was observed that the inoculum concentration at 4 × 106 CFU/ml had the highest dry weight reduction of 98.60% and mortality rate of 89.4%. Groundnut husks gave comparatively the best spore yield (9.8 × 107 CFU/g), and yam peels gave the least (1.1 × 107 CFU/g). Greenhouse and field trials showed that the strain C1136 had a strong antagonistic effect on the test weed. This study therefore confirms the suitability of the strain C1136 as a potentially effective bioherbicidal agent that is eco-friendly. Furthermore, the cheap strain’s observed responses to the environmental parameters assessed in the study affirmed its sustainability and possibility as a permanent substitute for synthetic herbicides in agrosystems’ practices for effective weed management.

Bioherbicides: revolutionizing weed management for sustainable agriculture in the era of One-health

Article

Full-text available

Apr 2025

Compositional Optimization for Miticidal Activity, Ecotoxicity, and Phytotoxicity of Rosmarinus officinalis Essential Oils as Biorational Pesticides

Article

Sep 2024
J AGR FOOD CHEM

Parthenium hysterophorus (congress grass) a unwanted plant & its uses

Article

Full-text available

Jan 2023

In right now we are confronting the pervasion of Parthenium hysterophorus all over the place. It is accessible in stocks around the rail route tracks, in exposed lands, in farming fields, in plantations and in backwoods, it attacks significant part of Indian mainland. We are knowing all about Parthenium hysterophorus poisonous properties and need to control its invasion. Nonetheless, just controlling its isn't an answer eliminate it however it very well may be overseen by means of its use for various purposes. As of late a ton of exploration has been proceeding to investigate the use properties of Parthenium. This survey article presents a few properties and utility capability of Parthenium finished up by different scientists.

Allelopathic effect of seed extract of Dactylis glomerata L. and Bromus inermis L. on germination potential and vegetation traits of Medicago sativa and Medicago scutellata

Article

Full-text available

Feb 2024

Allelopathy is one of abiotic stresses that causes changes in the plant metabolic pathways, reductions in seed germination and its growth. In order to investigate the allelopathic effects of B. inermis and D. glomerata rangeland species on germination potential (percentage and rate) and primary growth indices (seedling vigority, root length and shoot length) of M. sativa and M. scutellata, a study was conducted based on a completely randomized design (CRD) with four replications and under laboratory condition. The treatments consisted of aqueous extract of seeds of B. inermis and D. glomerata with 0 (control), 50, 100, 200, 300 and 400 (mg/l) concentration levels was applied on the seeds of Medicago. The results of analysis of variance showed a significant allelopathic effect of extract concentration on measured traits of the seed. The comparisons of the average indices also indicated that the increase in the extract concentration caused a decrease in the percentage of germination, germination rate, seedling vigority, root length and shoot length. So that, the highest rate and percentage of germination was observed in the control treatment and the least in the concentration of 400 mg/l. Considering the higher germination of M. scutellata at different concentration levels, it can be conducted that the extracts used in this experiment on M. sativa had a more inhibitory effect, which can cause a decrease in rangeland fodder productivity. As a result, it is recommended to cultivate Medicago spp. in rangelands together with the plants that have the least inhibitory effect on it.

A Weed of Global Significance Parthenium hysterophorus L.: An Overview of two faces of Parthenium weeds

Article

Full-text available

Jun 2024

Plant as Potential Resources for Efficacious Essential Oils: Underpinning Aromatherapy Evolution

Chapter

Full-text available

Apr 2024

Aromatherapy is a medical practice that uses aromatic compounds or essential oils to influence mood and health. Essential oils used in aromatherapy are created from a wide variety of medicinal plants, flowers, herbs, roots, and trees that are found all over the world and have significant, well-documented benefits on enhancing physical, emotional, and spiritual wellbeing. This book is a comprehensive reference on aromatic compounds present in essential oils and their therapeutic use. Starting from fundamentals of essential oil biosynthesis the book guides the reader through their basic biochemistry, toxicology, profiling, blending and clinical applications. The concluding chapters also present focused information about the therapeutic effects of essential oils on specific physiological systems, plant sources, skin treatment and cancer therapeutics. The combination of basic and applied knowledge will provide readers with all the necessary information for understanding how to develop preclinical formulations and standard clinical therapies with essential oils. This is an essential reference for anyone interested in aromatherapy and the science of essential oils.

Evaluating the application of yarrow (Achillea wilhelmsii) essential oil nanoemulsion on germination indices of purslane (Portulaca oleracea) and rye (Secale cereale)

Article

Full-text available

Sep 2023

Abstract: Extended Abstract Introduction: Weeds are one of the most important problems in agriculture and cause a lot of damage to crops. Overconsumption of herbicides in recent decades has led to harmful impacts on the environment and living organisms, including humans. In order to deal with these problems today, efforts are being made to reduce reliance on artificial herbicides and change direction towards sustainable agriculture as a part of integrated weed management. Among natural compounds, essential oils, which are components of aromatic and medicinal plants, were investigated to discover new herbicides. Material and Methods: In order to investigate the effects of yarrow essential oil (Achillea wilhelmsii C. Koch) on the germination and growth of purslane (Portulaca oleracea L.) and rye (Secale cereale L.) seedlings, two factorial experiments were conducted in the form of a completely randomized design in three replicates at Islamic Azad University, Science and Research Branch. The first factor was the type of essential oil in two levels (normal and nanoemulsion) and the second factor was the concentration of essential oil in six levels (0, 100, 200, 400, 800, and 1000 µl L-1). Results and Discussion: Scanning electron microscopy images showed the particles were relatively sperhical and their size varied from 1 to 100 nm. The zeta potential of the nanoparticles was -13.8 mV, indicating particle stability. Both type of essential oils reduced germination percentage, germination rate, plumule length, radicel length and seedling dry weight of both weeds and germination percentage decreased significantly with increasing concentration. At a concentration of 200 µl L-1, purslane treated with essential oil germinated 55.25%, but at the same concentration, the germination percentage of seeds treated with nanoemulsion of essential oil was 30.50%. Nanoemulsion of essential oil at concentration of 800 µl L-1 was able to completely prevent the germination and growth of purslane seedlings. Nanoemulsion of essential oil at a concentration of 1000 µl L-1 completely prevented rye seed germination. Germination rate decreased under treatment of yarrow essential oil and there was no difference between two types of essential oils at concentration of 200 µl L-1, but at a concentration of 800 µl, the germination rate of rye seeds treated with nanoemulsion of essential oil and ordinary essential oil reached to 1.40 and 0.32, respectively which was a significant difference. Conclusions: The inhibition percentage of the studied traits in both weed species showed that the essential oil nanoemulsion was more effective than the normal essential oil. Yarrow essential oil was more effective on purslane weed compared to rye. Essential oils do not have similar effects on weeds and their inhibitory effects will be different depending on the concentration and species of weeds, and the selectivity of these compounds should be investigated. The production of nano essential oil of yarrow as a natural herbicide is a solution. It offers to control weeds in organic farming systems.

Effect of Time and Burial Depth on Breaking Seed Dormancy and Percentage of Germination of Myagrum (Myagrum perfoliatum L.) Weed Seeds

Article

Full-text available

Jul 2021

Introduction: The internal factors of seeds and the conditions outside the seeds can affect the germination and emergence of seeds. In some cases, environmental conditions are suitable for seed to germinate, while the seeds do no seed dormancy which is regarded to be one of the factors in seed survival. Seeds are exposed to different conditions of temperature fluctuations, moisture fluctuations, activity of microorganisms, etc. by being located at different depths of the soil. For instance, seeds that are located in the surface layers of the soil are more exposed to soil moisture fluctuations, which may also affect their dormancy. The results of various experiments have shown that in addition to the depth of burial of seeds, their burial time also affects their germination. Due to the fact that no experiments have been performed on the germination of myagrum weed seeds in this field, this study was conducted to investigate the effect of time and burial depth on breaking seed dormancy and percentage of germination of myagrum. Materials and Methods: This study aimed to investigate the effect of burial time and burial depth on breaking seed dormancy and germination of myagrum seeds in factorial experiment based on a randomized complete block design with 4 replications in the research farm of Razi University of Kermanshah in 2014-2015. Experimental factors include burial time (270, 360 and 420 days), burial depth (0, 5, 10, 20 and 40 cm), temperature (25 ° C, 5/10 and 10/20 °C variable temperature) and light (light and dark). In June 2014, myagrum seeds were collected from plants that had become mature and were in the full mature stage stored in plastic nylon at 25 °C until the seeds were tested. At the beginning of the experiment, the seeds were packed in lace bags that had small pores from which the seeds could not exit and then placed at different depths of the farm soil. 340 seeds were placed in each lace bag. The lace bags were such that the seeds were exposed to the moisture, temperature and chemical regimes of the soil. To make it easier to exit the lace bags from the soil, a thread was attached to each bag that was placed on the soil surface. After each level of burial time in the soil (270, 360 and 420 days), lace bags were exited from different depths .Firstly, the number of germinated seeds in each lace bag was counted and the germination percentage was calculated .Germinated seeds were then removed from the bags and the residual of seeds was transferred to the Agriculture Laboratory of the Agricultural and Natural Resources Campus of Razi University .The results of Mondani et al. (16) study showed that myagrum seeds have physiological dormancy and mechanical dormancy due to hard outer shell .Therefore, seeds do not germinate included damaged seeds and seeds had physiological dormancy and mechanical dormancy. Extracted seeds (not germinated seeds) from different depths in each burial time were disinfected in sodium hypochlorite solution (2%) for ten minutes. Then, to ensure the viability of the seeds, a number of seeds of any depth were randomly selected and tested using tetrazolium solution (0.1%). The appearance of red color indicated the existence of respiration and viability of the seeds (13). To remove the mechanical dormancy caused by the hard outer shell in the seeds, the outer shell of the seeds was removed and then the seeds were placed in sterile petri dish with a diameter of 7 cm containing Whatman No. 1 filter paper and 5 ml of distilled water (30 seeds were placed in per petri dish) and to prevent water evaporation, the petri dishes were closed with parafilm. The petri dishes were then exposed to different temperatures (25 °C, 5/10 and 10/20 °C variable temperature) inside the germinator and in light and dark conditions. To exert the effect of darkness, petri dishes were wrapped in an aluminum foil. After 14 days, the number of germinated seeds in each petri dish was counted. Germination criterion was visible root exit. Finally, data analysis was performed by SAS (version 9.4) software and mean comparisons were performed based on Duncan at 5% probability. Results and Discussion: The results showed the germination percentage of myagrum weed seeds in light and dark were not significantly difference, and also seed burial time, temperature, burial depth and burial time * temperature interaction had a significant effect (p ≤ 0.01) on the germination percentage. The highest germination percentage was observed after 420 days of burial at a variable temperature of 10/20 °C. Also, at the soil surface and with the increasing seed burial depth (more than 5 cm) the survival and seed germination percentage decreased compared to soil depth of 5 cm because seeds need special moisture and temperature conditions for germination. According to the results, these conditions existed at a depth of 5 cm in the soil, so it can be concluded that deep plowing and going -deep seeds may help to manage this weed. Conclusion: Considering that the highest germination percentage was observed in the temperature regime of 10/20 °C, it can be assumed that this weed can be problematic in summer and autumn crops because this temperature range synchronizes in late winter and early spring. On the other hand, it is possible to control this weed in wheat fields. In fact, in wheat fields, herbicides such as 2,4-D and MCPA are used to control broad-leaf weeds in late March and early April, when the temperature is about 10/20 ° C and the time of germination and emergence of myagrum is used. However, if this weed appears in chickpea fields, it is difficult to control because there is no specific herbicide in chickpea fields to control broadleaf weeds, including myagrum. Also, as the depth of burial increased, the germination percentage of the seeds decreased, so deep plowing and deepening of the seeds may help to manage this weed.

RECENT ADVANCES IN WEED MANAGEMENT THROUGH HERBAL HERBICIDE

Chapter

Full-text available

Oct 2023

Weeds cause higher crop losses than any other crop pests, although they are underestimated in tropical agriculture. Controlling composite weed cultures in the agricultural field is tough. Many synthetic herbicides have been used in weed management practices during last 50 years. Initiatives are being made to reduce the strong dependence on synthetic herbicides, which may negatively impact on human health and the environment. Natural/herbal products, including essential oils, plant extracts, allelochemicals, and agricultural byproducts, are gaining popularity as an alternative to synthetic herbicides since they are harmless due to their short environmental half-lives and low toxicity. Since they strongly emphasize environmental conservation, practical viability, compatibility with integrated programs, and ecological stability, these natural/herbal herbicides are excellent substitutes for synthetic herbicides, particularly in organic agriculture. Herbal herbicides appear to be useful for weed control in sustainable agriculture. These herbal herbicides, in judicious combination with other weed management practices, would be a potential tool for combating weed problems in agriculture. Keywords: Crop loss, herbal products, essential oils, plant extracts, allelochemicals, agricultural byproducts, weed management.

Chemodiversity and α-Glucosidase Activity of Eucalyptus Species from Northwestern Himalaya, India

Article

Jul 2023
CHEM BIODIVERS

Sachin Vashisath

The aim of current work was to determine essential oils (EOs) composition from three Eucalyptus species, including E. citriodora, E. camaldulensis and E. globulus and assess their α-glucosidase inhibitory activity. The EOs were collected using the hydrodistillation technique and characterized by GC/MS, GC-FID and NMR. The isolated EOs from leaves parts of Eucalyptus species varied from 0.56 to 1.0% on fresh weight basis. The content of the EOs was distinct according to the species. The most abundant metabolites were identified as citronellal (0-83.0%), 1,8-cineole (0.2-44.8%), spathulenol (0.4-16.1%) α-pinene (0.4-15.9%), p-cymene (3.7-11.9%), citronellol (0-8.6%), β-eudesmol (5.3-8.6%) and β-pinene (0-7.1%). The EOs obtained from targeted samples exhibited strong α-glucosidase inhibitory activity. These results are encouraging and underline that the EOs of Eucalyptus species may be a promising alternative source of natural antidiabetic.

EFFECT OF CRUDE OIL EXPLORATION ON GLOBAL FOOD SECURITY: A REVIEW

Article

Full-text available

May 2023

Crude oil exploration activities have impacted the land, air, and water negatively in places where such activities are taking place. These impacts generally imply low soil fertility, which in turn implies low agricultural productivity and a reduced source of livelihood in affected areas. Its effect also includes the loss of major soil nutrients that are necessary for food and fiber production. Several research papers were reviewed on the effects of crude oil exploration on global food production and efforts being made to alleviate this negative impact. The reviewed literatures includes places where crude oil exploration activities have been carried out. Several works of literatures reviewed indicated that there is a downward decline in food production due to the severe nature of damage to the environment as a result of crude oil spill on the environment. Consequently, there have been significant advances in regulation for protecting the environment in developed and developing countries, including the development of remediation frameworks and guidelines. On the other hand, studies have rarely reported on the risks and health effects of contaminants in developing regions and there is scarce information regarding contaminated land assessment and environmental remediation. Coordinated efforts are needed to increase the production of food but to remediate the impact on the environment to a level that will not hinder food production and threat to well-being of the inhabitants of these places where exploration is taking place.

Parthenium weed

Research Proposal

Full-text available

Jan 2023

Biology, distribution and management of the globally invasive weed Solanum elaeagnifolium Cav (silverleaf nightshade): A global review of current and future management challenges

Article

Oct 2022

Solanum elaeagnifolium Cav (silverleaf nightshade) is a deep‐rooted, multi‐stemmed, perennial, herbaceous woody plant that has been observed to threaten agricultural and native biodiversity worldwide. It is widely agreed that without efficient integrated management, S. elaeagnifolium will continue to cause significant economic and environmental damage across multiple scales. It is estimated that the annual economic impact of S. elaeagnifolium in Australia exceeds AUD $62 million, with this figure likely to be much higher in other countries invaded by this plant. It can also tolerate a high level of abiotic stress and survive in a range of temperatures (below freezing point to 34°C) and areas with an average yearly rainfall between 250 and 600 mm. Its extensive deep taproot system is capable of regenerating asexually and with its many seed dispersal mechanisms; it can quickly spread and establish itself within a region. This makes containment and management of the species especially challenging. Previous management has largely been focused on biological control, competition, essential oils, grazing pressure, herbicide application and manual removal. Despite the large range of available management techniques, there has been little success in the long‐term control of S. elaeagnifolium, and only a handful of methods such as essential oils and herbicide application have shown reasonable success for controlling this weed. Therefore, this review aims to synthesise the identified and potentially useful approaches to control S. elaeagnifolium that have been recorded in the literature which deal with its biology, distribution and management. It also explores previous and current management techniques to ascertain the research gaps and knowledge required to assist in the effective and economically sustainable management of this invasive weed.

Emergence and establishment of mosses and ferns from spore banks after exposure to glyphosate and two bioherbicides

Article

May 2022

Herbicides are used extensively to control invasive plants in natural areas but, herbicide application often has undesired effects on non-target plants. Using a lab bioassay, we investigated the impacts of glyphosate and two bioherbicides (cinnamon plus clove oil, and pelargonic acid) on the establishment of bryophyte and fern propagules from an urban woodland park soil propagule bank. Mosses were slower to emerge and establish in soil treated with cinnamon plus clove oil than soil treated with pelargonic acid or glyphosate. Fern gametophyte establishment was negatively affected by glyphosate but not by the two bioherbicides. Results from this study confirmed those of a previous field study indicating that an herbicide containing pelargonic acid could be useful for controlling non-native plants in locations suspected of harboring high biodiversity in soil propagule banks.

Allelopathic effect of herbal formulation containing Ferula assa-foetida L. essential oil and castor oil ( Ricinus communis L.) as an herbicide on Amaranthus retroflexus L. seed germination

Article

Full-text available

Dec 2021

Background: Medicinal plant contain phytochemicals which have inhibitory effects on plant pathogens. Weeds compete with the main crops and reduce the growth, yield, and quality of agricultural products to some extent. One of the most common methods of reducing weed damage is the use of chemical herbicides. Due to the side effects that chemical herbicides on human health and the environment, there is a need to replace biocompatible and low-risk herbicides. Objective: In this study, the allelopathic properties of the Ferula assa-foetida L. essential oil and castor oil (Ricinus communis L.) have been investigated as a botanical herbicide to prevent germination of redroot pigweed seeds (Amaranthus retroflexus L.). Methods: In this regard, an herbal formulation based on Ferula assa-foetida essential oil and castor oil was prepared and its effect on the germination of redroot pigweed seeds was studies in laboratory conditions. The chemical composition of the herbal formulation was analyzed by GC/MS. Results: The results showed that this herbal formulation in concentration 0.75 % and 1 % inhibits the germination of weed seeds about 70 %. The main constituents of Ferula assa-foetida and Ricinus communis were (E)-1-propenyl sec-butyl disulfide (43.9 %) and ricinoleic acid methyl ester (58.1 %), respectively. Conclusion: It was found that the studied botanical formulation has herbicidal properties. Therefore, more research is needed to achieve promising results in order to replace chemical herbicides with botanical herbicides.

Herbicidal Potential and Identification of Allelochemicals from Moringa oleifera

Article

Dec 2021
Asian J Plant Sci

Effets des Huiles Essentielles de Ocimum gratissimum L. et de Cymbopogon citratus Stapf sur les Paramètres de Croissance et de Production du Cotonnier en Côte d'Ivoire Effects of Essential Oils of Ocimum gratissimum L. and Cymbopogon citratus Stapf on the Growth and Production Parameters of Cotton Plant in Côte d'Ivoire

Article

Full-text available

Sep 2019

L'objectif du travail effectué, était de montrer l'action des huiles essentielles, de deux plantes aromatiques avérées pesticides (Ocimum gratissimum et Cymbopogon citratus), sur les paramètres agromorphologiques du cotonnier. Les huiles essentielles ont Effets des Huiles Essentielles de Ocimum gratissimum L. et de Cymbopogon citratus Stapf sur les Paramètres de Croissance et de Production du Cotonnier en Côte d'Ivoire 22 été extraites et caractérisées. Au champ, les cotonniers ont été soumis aux effets des extraits huileux et d'un insecticide chimique par pulvérisation foliaire toutes les deux semaines du 45 ème au 115 ème jour après la levée. Les résultats ont révélé que l'extrait de O. gratissimum renfermait de fortes proportions en monoterpènes hydrocarbonés tandis que celui de C. citratus était riche en éléments oxygénés. A la concentration de 5 %, les huiles essentielles ont significativement freiné la croissance caulinaire des cotonniers (0,49 cm/j). A cette teneur, les cotonniers traités avec l'extrait de C. citratus ont obtenu le nombre le plus faible de capsules vertes (9,61 capsules/plantes) contrairement à celui de O. gratissimum (12,55 capsules/plante) et du produit chimique (13,15 capsules/plante). A la production, les cotonniers traités avec l'insecticide de synthèse ont présenté de plus fortes valeurs de poids moyen capsulaire (2,03 g), de rendement en graine (53,63 %), de poids de 100 graines ou seed index (7,55 g) et de meilleur rendement en coton-graine (963,28 kg/ha). Cependant, l'application des huiles essentielles a induit l'obtention d'un bon rendement en fibres (44,16 %). Relativement à la chute des organes, les produits évalués n'ont pas provoqué de façon significative l'abscission des capsules vertes. Globalement, les cotonniers protégés avec l'extrait de O. gratissimum ont été plus productifs que ceux traités avec celui de C. citratus. Abstract The objective of this work was carried out to show the action of essential oils, of two proven pesticidal aromatic plants (Ocimum gratissimum and Cymbopogon citratus), on the agromorphological parameters of cotton plants. The essential oils have been extracted and characterized. In the field, cotton plants were subjected to the effects of extracts and a chemical insecticide by foliar spraying every two weeks from 45 to 115 days after emergence. The results revealed that the extract of O. gratissimum contained high proportions of hydrocarboned monoterpenes while that of C. citratus was rich in oxygenated elements. At a concentration of 5 %, essential oils significantly slowed down the stem growth of cotton plants (0.49 cm/d). At this level, cotton plants treated with C. citratus extract obtained the lowest number of green bolls (9.61 bolls/plants) as opposed to O. gratissimum (12.55 bolls/plant) and chemical (13.15 bolls/plant). At production, cotton plants treated with synthetic insecticide had higher values for capsular average weight (2.03 g), seed yield (53.63 %), seed index (7.55 g) and higher seed cotton yield (963.28 kg/ha). However, the application of essential oils resulted in a good fibre yield (44.16 %). With regard to organ failure, the products evaluated did not significantly cause the shedding of the green bolls. Overall, cotton plants protected with O. gratissimum extract were more productive than those treated with C. citratus.

‫Allelopatic Effects of Capparis spinosa, Herttia angustifolia and Peganum harmala on Germination and Seedling Growth of Wheat and Alfalfa ‬

Article

Full-text available

Aug 2021

An experiment was conducted to investigate the allelopathic effect of three range species, C. spinosa, P. harmala and H. angustifolia on germination and seedling growth of alfalfa and wheat. The experiment was performed at the Faculty of Natural Resources, Yazd University, in 2002. A completely randomized design with three replications was carried out in a factorial combination of three plant extracts (C. spinosa, P. harmala and H. angustifolia) and distilled water as control, two extract concentrations (50% and 100%) and two target species (alfalfa and wheat). Results indicated that the C. spinosa extract caused the greatest inhibitory effect on test plants. Reductions in seed germination, shoot length and weight were 86, 98 and 99%, respectively compared to control. Results of this experiment also showed that C. spinosa extract had a highly significant inhibitory effect on root length and weight when compared to control. Between two concentrations, 100% concentration has more inhibitory effect on the average of germination and shoot weight as well as shoot length. But, there was no significant difference between root weight and root length. The results of this experiment also showed that the inhibitory effects of both concentrations were higher on alfalfa than wheat.

Effects of allelochemicals on plant respiration and oxygen isotope fractionation by the alternative oxidase

Article

Full-text available

Apr 1996

The goal of this investigation was to determine the effects of allelochemicals on plant respiration that thereby may be responsible for their role in growth inhibition. We have tested the effects of juglone, quercetin, cinnamic acid, andα-pinene on respiration rates, and electron partitioning through the cytochrome and alternative respiratory pathways, by measuring on-line oxygen consumption and oxygen isotope fractionation in soybean cotyledon tissue. Cinnamic acid andα-pinene decreased the oxygen consumption rate and increased the relative partitioning of electron transport to the alternative pathway. Possible biochemical mechanisms of these effects are discussed.

Essential Oils as Allelochemicals and Their Potential Use as Bioherbicides

Article

Full-text available

May 1999

Essential oils were extracted from 32 aromatic plants and evaluated for allelopathic properties. The major components of the oils were identified by gas chromatography and GC-MS. Extracts from Origanum syriacum, Micromeria fruticosa, and Cymbopogon citratus were selected for further study. The germination of several species, including wheat, was strongly inhibited by essential oils when applied at 20–80 ppm. Essential oils mixed with the top 0.5 cm of soil inhibited germination of wheat and Amaranthus seeds. This effect depended on the type of soil. The possible use of essential oils as herbicides is discussed.

Mechanisms of membrane toxicity of hydrocarbons.

Article

Jun 1995
Microbiol Rev

Microbial transformations of cyclic hydrocarbons have received much attention during the past three decades. Interest in the degradation of environmental pollutants as well as in applications of microorganisms in the catalysis of chemical reactions has stimulated research in this area. The metabolic pathways of various aromatics, cycloalkanes, and terpenes in different microorganisms have been elucidated, and the genetics of several of these routes have been clarified. The toxicity of these compounds to microorganisms is very important in the microbial degradation of hydrocarbons, but not many researchers have studied the mechanism of this toxic action. In this review, we present general ideas derived from the various reports mentioning toxic effects. Most importantly, lipophilic hydrocarbons accumulate in the membrane lipid bilayer, affecting the structural and functional properties of these membranes. As a result of accumulated hydrocarbon molecules, the membrane loses its integrity, and an increase in permeability to protons and ions has been observed in several instances. Consequently, dissipation of the proton motive force and impairment of intracellular pH homeostasis occur. In addition to the effects of lipophilic compounds on the lipid part of the membrane, proteins embedded in the membrane are affected. The effects on the membrane-embedded proteins probably result to a large extent from changes in the lipid environment; however, direct effects of lipophilic compounds on membrane proteins have also been observed. Finally, the effectiveness of changes in membrane lipid composition, modification of outer membrane lipopolysaccharide, altered cell wall constituents, and active excretion systems in reducing the membrane concentrations of lipophilic compounds is discussed. Also, the adaptations (e.g., increase in lipid ordering, change in lipid/protein ratio) that compensate for the changes in membrane structure are treated.

VOLATILE GROWTH INHIBITORS PRODUCED BY SALVIA LEUCOPHYLLA: EFFECTS ON SEEDLING ROOT TIP ULTRASTRUCTURE

Article

Feb 1976

Volatile monoterpenes emanating from leaves of Salvia leucophylla (Labiatae) are responsible for anatomical and physiological changes occurring in herb seedlings which were exposed to the vapors. Examination of treated root tip cells from Cucumis sativus by electron microscopy revealed widespread systemic disturbances. These included the accumulation of globules which appear to be lipid in nature in the cytoplasm, a drastic reduction in the number of a variety of intact organelles including mitochondria, and a disruption of membranes surrounding nuclei, mitochondria, and dictyosomes. These effects, coupled with the effects of environmental stress, may account for the failure of herb seedlings to survive in the areas adjacent to Salvia thickets.

Parthenium hysterophorus: A review of its weed status and the possibilities for biological control

Article

Jan 1997

H.C. Evans

Microbial contamination in milk

Article

May 2011

Because milk and milk products are highly perishable foods, high standards are required for a successful and profitable dairy industry. The milk leaving the farm must be of good nutritional and bacteriological quality and be uncontaminated by soil and chemical pollutants.

Effect of essential oil vapours of different concentrations upon leaf transpiration of bean and sunflower

Article

Jan 1986

Managing weeds with natural products

Article

Jan 1999
Pestic Outlook

Tagetes minuta and Schinus areira essential oils as allelopathic agents

Article

Jun 2003
BIOCHEM SYST ECOL

The bioassay of T. minuta and S. areira oils and their pure principal components revealed strong inhibitory activity of the root growth of Zea mays seedlings. Both T. minuta and S. areira oils treatment presented an increase in malondialdehyde values from 24 to 48 h, while the main components of the essential oils, ocimenone, alpha-pinene and limonene, presented an increase from 24 to 96 h indicating lipid peroxidation. The T. minuta essential oil had a greater inhibitory action and oxidant effect on the root of Zea mays than S. areira oil.

Volatile Growth Inhibitors Produced by Salvia Species

Article

Jul 1964

The leaves of Salvia leucophylla, S. mellifera, and S. apiana have been shown to contain the following terpenes: α-pinene, camphene, β-pinene, cineole, dipentene, and camphor. Such terpenes also are present in the atmosphere above macerated leaves of these species. Camphor and cineole are the most inhibitory materials and the pinenes are the least inhibitory. It is suggested that the inhibition of growth of annual grassland species in and about colonies of Salvia is due to the production of volatile terpenes, especially camphor and cineole.

Muller, C. H. Inhibitory terpenes volatilized from Salvia shrubs. Bull. Torrey Bot Club

Article

Jan 1965

Cornelius H. Muller

Gas chromatography studies have shown that the air around Salvia leucophylla and S. mellifera (growing either in the field or in the greenhouse) contains two terpenes, apparently cineole and camphor. These terpenes are known to be more toxic than other terpenes that occur in the plants. The several terpenes of S. leucophylla are highly soluble in hard paraffin, suggesting that they are taken into the seedlings they inhibit by solution in the cutin of the mesophyll.

Just how soluble are monoterpenes?

Article

Aug 1993

Prior generalizations about the ecological roles of monoterpenes may be misleading if based on the presumed insolubility of monoterpenes in water. We determined the aqueous solubility of 31 biologically active monoterpenes by gas chromatography. While hydrocarbons were of low solubility (< 35 ppm), oxygenated monoterpenes exhibited solubilities one or two orders of magnitude higher, with ranges of 155-6990 ppm for ketones and of 183-1360 ppm for alcohols. Many monoterpenes are phytotoxic in concentrations under 100 ppm, well below the saturated aqueous concentrations of oxygenated monoterpenes. Therefore, even dilute, unsaturated solutions of monoterpenes, occurring naturally in plant tissues and soil solutions, may act as potent biological inhibitors.

In search of allelopathy in the Florida scrub: The role of terpenoids

Article

Jun 1994

The hypothesis was tested that allelopathic agents released from fire-sensitive plants of the Florida scrub community deter the invasion of fireprone sandhill grasses. The structures of the constituents of four endemic scrub species,Conradina canescens, Calamintha ashei, Chrysoma pauciflosculosa, andCeratiola ericiodes, were established and their phytotoxic activity against two grasses of the sandhill was examined. Effects of the secondary metabolites from the above scrub species and their degradation products upon the germination and radicle growth of little bluestem (Schizachyrium scoparium) and green sprangletop (Leptochloa dubia), two native grasses of the Florida sandhill community, were determined. The studies included determination of the water solubility and release mechanism of terpenes and other allelopathic agents from the source plants and their aqueous transport to the target species. Some of the natural products were nontoxic until activated by light and/or oxidation after release from the source plant into the environment.

Higher plant terpenoids: A phytocentric overview of their ecological roles

Article

Jun 1994

Jean H. Langenheim

Characteristics of higher plant terpenoids that result in mediation of numerous kinds of ecological interactions are discussed as a framework for this Symposium on Chemical Ecology of Terpenoids. However, the role of terpenoid mixtures, either constitutive or induced, their intraspecific qualitative and quantitative compositional variation, and their dosage-dependent effects are emphasized in subsequent discussions. It is suggested that little previous attention to these characteristics may have contributed to terpenoids having been misrepresented in some chemical defense theories. Selected phytocentric examples of terpenoid interactions are presented: (1) defense against generalist and specialist insect and mammalian herbivores, (2) defense against insect-vectored fungi and potentially pathogenic endophytic fungi, (3) attraction of entomophages and pollinators, (4) allelopathic effects that inhibit seed germination and soil bacteria, and (5) interaction with reactive troposphere gases. The results are integrated by discussing how these terpenoids may be contributing factors in determining some properties of terrestrial plant communities and ecosystems. A terrestrial phytocentric approach is necessitated due to the magnitude and scope of terpenoid interactions. This presentation has a more broadly based ecological perspective than the several excellent recent reviews of the ecological chemistry of terpenoids.

Volatile Growth Inhibitors Produced by Salvia leucophylla: Effects on Seedling Root Tip Ultrastructure

Article

Feb 1976

Interactions Involving Allelopathy in Cropping Systems

Article

Nov 1996

Frank A. Einhellig

Allelopathic inhibition typically results from the combined action of a group of allelochemicals which, collectively, interfere with several physiological processes. The objectives of this paper are to summarize research that illustrates the joint action of allelochemicals, and to provide evidence that both the amount and detrimental action of these compounds depends an the extent of associated abiotic and biotic stresses. Allelopathy is strongly coupled with other stresses of the crop environment, including insects and disease, temperature extremes, nutrient and moisture variables, radiation, and herbicides. These stress conditions often enhance allelochemical production, thus increasing the potential for allelopathic interference. In the paradigm of interactions, the data indicate that crops are more sensitive to allelopathy when moisture, temperature, or nutrient conditions are less than optimal. For example, the inhibition threshold concentration for ferulic acid to affect seedling growth was reduced with even minor moisture stress (ψ = -0.15 MPa) or a growth temperature at the higher end of the normal range for a species. Under greenhouse conditions, additive inhibition resulted from the joint action of ferulic acid with low levels of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], or trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine]. Interactions of multiple stresses in crop environments will determine the relative impact of allelopathy. Allelopathy-stress interactions also have implications for herbicide and residue management strategies, crop rotations, biological control measures, and tillage practices that can contribute to a more sustainable agriculture.

Allelopathic impact of volatile components fromEucalyptus on crop plants

Article

Nov 1991

The effect of crude volatile oils from the leaves ofEucalyptus globulus andE. citriodora and the pure terpenes - cineole and limonene from these oils, (in vapour form) was studied onPhaseolus aureus, Lens esculentum, Hordeum vulgare and Avena sativa. The parameters like germination of seeds, seedling growth, values of cell survival, and content of water and chlorophyll of the crops formed the system of bioefficacy study. The allelopathic impact of the oil vapours from the eucalypt tree becomes evident from the negative response of the parameters studied. The impact of the E. citriodora oil vapours compared to that ofE. globulus oil or the pure terpenes was seen to be relatively greater in almost all parameters under investigation. A strong reciprocal correlation that exist between the concentration and the seedling growth or the water content of the crops under study supports the dose linked allelopathic phenomenon. It is suggested that oil vapours ofEucalyptus exert their effect through impairing the respiratory as well as photosynthetic ability of the target plants.

Secondary Compounds as Protective Agents

Article

Nov 2003
Annu Rev Plant Physiol

T Swain

Tworkoski, T. Herbicide effects of essential oils. Weed Sci.

Article

Jan 2009

Thomas Tworkoski

Laboratory and greenhouse experiments were conducted to determine the herbicidal effect of plant-derived oils and to identify the active ingredient in an oil with herbicide activity. Twenty-five different oils were applied to detached leaves of dandelion in the laboratory. Essential oils (1%, v/v) from red thyme, summer savory, cinnamon, and clove were the most phytotoxic and caused electrolyte leakage resulting in cell death. Each of these essential oils in aqueous concentrations from 5 to 10% (v/v) plus two adjuvants (nonionic surfactant and paraffinic oil blend at 0.2% [v/v]) were applied to shoots of common lambsquarters, common ragweed, and johnsongrass in the greenhouse; shoot death occurred within 1 h to 1 d after application. Essential oil of cinnamon had high herbicidal activity, and eugenol (2-methoxy-4-[2-propenyl]phenol) was determined to be this oil's major component (84%, v/v). Dandelion leaf disk and whole-plant assays verified that eugenol was the active ingredient in the essential oil of cinnamon. Essential oils are extracted from plants and thus may be useful as “natural product herbicides” for organic farming systems. Nomenclature: Cinnamon, Cinnamomum zeylanicum; clove, Syzgium aromaticum; red thyme, Thymus vulgaris; summer savory, Satureja hortensis; common lambsquarters, Chenopodium album L. CHEAL; common ragweed, Ambrosia artemisiifolia L. AMBEL; dandelion, Taraxacum officinale Weber in Wiggers TAROF; johnsongrass, Sorghum halepense (L.) Pers. SORHA.

Natural products as sources of herbicides: Current status and future trends

Article

Jan 2002
WEED RES

Although natural product-based discovery strategies have not been as successful for herbicides as for other pesticides or pharmaceuticals, there have been some notable successes. Phosphinothricin, the biosynthetic version of glufosinate, and bialaphos are phytotoxic microbial products that have yielded commercial herbicides. Cinmethylin, a herbicidal analogue of cineole, has been sold in Europe and Asia. The triketone herbicides are derivatives of the plant-produced phytotoxin leptospermone. These products represent only a small fraction of commercialized herbicides, but they have each introduced a novel molecular target site for herbicides. Analysis of the literature reveals that phytotoxic natural products act on a large number of unexploited herbicide target sites. The pesticide industry’s natural product discovery efforts have so far concentrated on microbially derived phytotoxins, primarily from non-pathogenic soil microbes, involving the screening of large numbers of exotic isolates. Plant pathogens usually produce potent phytotoxins, yet they have received relatively little attention. Even less effort has been made to discover plant-derived phytotoxins. Bioassay-directed isolation has been the preferred method of discovery after a producing organism is selected. This laborious approach often leads to rediscovery of known compounds. Modern tandem separation/chemical characterization instrumentation can eliminate much of this problem by identification of compounds before they are bioassayed.

Comparative phytotoxicity of four monoterpenes against Cassia occidentali

Article

Mar 2005
ANN APPL BIOL

The effect of four monoterpenes - citronellol, citronellal, cineole and linalool - on the germination, growth and physiology of Cassia occidentalis was investigated. All four monoterpenes reduced germination of C. occidentalis seeds but to varying extents. Citronellal and linalool completely inhibited germination beyond the concentrations of 55 and 110 μM, respectively, whereas in response to treatment of citronellol no germination was observed beyond 330 μM. Further, the growth of seedlings, measured in terms of seedling length and biomass, was also adversely affected. A reduction in chlorophyll content of the cotyledonary leaves of C. occidentalis was also noticed, indicating an adverse effect on photosynthesis. Likewise, respiratory ability of growing seeds was also impaired in response to all four monoterpenes, clearly indicating that monoterpenes affect energy metabolism. On the basis of overall phytotoxicity, potency of monoterpenes was in the order of citronellal > linalool > citronellol > cineole. The results from this study suggest that both citronellal and linalool possess strong phytotoxic potential and can thus serve as lead molecules for the synthesis of bioherbicides.

Terpenoids from Artemisia annua and constituents of its essential oil

Article

Sep 1994

The hexane extract of the aerial part of Artemisia annua yielded three new cadinanes along with several known compounds of which five have been iso

Fungicidal effect of volatile oils from Eucalyptus citriodora and its major constituent citronellal

Article

Aug 2002

A study was undertaken to explore the effect of volatile oils from Eucalyptus citriodora and its major constituent citronellal against two wellknown rice pathogens Rhizoctonia solani and Helminthosporium oryzae The radial growth and dry weight of both the test fungi were drastically reduced in response to the volatile oils A complete inhibition of R solani and H oryzae was observed at 10 and 20 ppm respectively Citronellal alone was found to be more effective than eucalypt oils Based on the study it was concluded that eucalypt volatile oils have potential for the suppression of phytopathogenic fungi

Allelopathic Effects of Volatile Cineoles on Two Weedy Plant Species

Article

Jan 2000

The volatile monoterpene analogs, 1,4-cineole and 1,8-cineole, have been identified as components of many plant essential oils, but relatively little is known about their biological activities. We compared the effects of 1,4- and 1,8-cineole on two weedy plant species by monitoring germination, mitosis, root and shoot growth, chlorophyll content, and photosynthetic efficiency. 1,4-Cineole severely inhibited growth of roots and shoots, causing cork-screw shaped morphological distortion, whereas 1,8-cineole caused a decrease in root growth and germination rates. Chlorophyll fluorescence data (yield and F v / F m) indicated that 1,4-cineole caused significantly higher stress (P 0.001) to photosynthesis when compared to controls. Mitotic index data showed that 1,8-cineole severely decreased (P 0.001) all stages of mitosis when compared with controls, while 1,4-cineole only caused a decrease in the prophase stage (P 0.05). Although superficially similar in structure, these two cineoles appear to have different modes of action.

Effects of Four Monoterpenes on Germination, Primary Root Growth, and Mitochondrial Respiration of Maize

Article

Jan 2000

The effects of four monoterpenes—camphor, eucaliptol, limonene, and -pinene—on the oxidative metabolism of mitochondria isolated from maize root (Zea mays), on maize seed germination, and on primary root growth were investigated. The effects of individual monoterpenes on respiration were variable. -Pinene concentrations of 0.05–1.0 mM stimulated respiration with a mixture of substrates composed of NADH, L-malate, succinate, and L-glutamate, and in the absence of exogenously added ADP (basal respiration). However, at concentrations higher than 1.0 mM, -pinene inhibited respiration both in the absence (basal respiration) and presence of ADP (coupled respiration). Limonene at 0.1 mM or above stimulated basal respiration and inhibited in parallel the coupled respiration. Similar effects were promoted by eucaliptol, but at a higher concentration range (1.0 mM or above). Camphor was less active. At 10 mM concentration, it caused stimulation of basal respiration but did not affect coupled respiration. In the concentration range 0.1–10.0 mM, limonene was inactive on seed germination and primary root growth. Camphor and eucaliptol did not inhibit germination but reduced fresh and/or dry weight of roots at 5.0 mM and above. -Pinene inhibited both seed germination and fresh weight of primary roots at 10.0 mM concentration. The results indicate that intact seeds and primary roots are less sensitive than isolated mitochondria. The relatively more lipophilic monoterpenes -pinene and limonene had less activity than the more water-soluble oxygenated monoterpenes camphor and eucaliptol in inhibiting seed germination and/or primary root growth, despite the fact that they had a higher activity on the oxidative metabolism of isolated mitochondria. The findings suggest that the solubility of monoterpenes may be the major factor implicated in these differences.

Morphogenetic Effect of the Herbicide Cinch on Arabidopsis thaliana Root Development

Article

May 1998

Cinch is a morphogenetically active herbicide that inhibits primary root growth and induces abnormal ``nodule-like'' lateral roots on Arabidopsis thaliana seedlings. Using 200 nm Cinch, the early stages of lateral root formation occurred along the apical half of the root axis; but once emerged, they were inhibited from further growth. Second-order lateral roots formed at the base of stunted first-order lateral roots after 5 days of Cinch treatment. Results from Cinch experiments suggested that pericycle cells are determined in the meristem to be potential sites of lateral root formation, and the developmental transition point between emerged lateral roots and subsequent growth is inhibited. Results using 2,4-dichlorophenoxyacetic acid and 2,3,5-triiodobenzoic acid suggest that Cinch is not a chemical analog of auxin.

Tagetes minuta and Schinus areira essential oils as allelopathic agents

Article

Jun 2003
BIOCHEM SYST ECOL

The bioassay of T. minuta and S. areira oils and their pure principal components revealed strong inhibitory activity of the root growth of Zea mays seedlings. Both T. minuta and S. areira oils treatment presented an increase in malondialdehyde values from 24 to 48 h, while the main components of the essential oils, ocimenone, α-pinene and limonene, presented an increase from 24 to 96 h indicating lipid peroxidation. The T. minuta essential oil had a greater inhibitory action and oxidant effect on the root of Zea mays than S. areira oil.

Plant essential oils for pest and disease management

Article

Sep 2000
CROP PROT

Murray B. Isman

Certain essential plant oils, widely used as fragrances and flavors in the perfume and food industries, have long been reputed to repel insects. Recent investigations in several countries confirm that some plant essential oils not only repel insects, but have contact and fumigant insecticidal actions against specific pests, and fungicidal actions against some important plant pathogens. As part of an effort aimed at the development of reduced-risk pesticides based on plant essential oils, toxic and sublethal effects of some essential oil terpenes and phenols have been investigated using the tobacco cutworm (Spodoptera litura) and the green peach aphid (Myzus persicae) as model pest species. In this paper I review (i) the range of biological activities of essential oils and their constituents; (ii) their toxicity and proposed mode-of-action in insects; (iii) their potential health and environmental impacts as crop protectants; and (iv) commercialization of pesticides based on plant essential oils.

Allelopathic effect of two volatile monoterpenes against bill goat weed (Ageratum conyzoides L.)

Article

May 2002
CROP PROT

A study was conducted to assess the allelopathic effect of two volatile monoterpenes viz. cineole and citronellol on Ageratum conyzoides with a view to explore the possibility of their exploitation for future weed management. Both the monoterpenes severely affected the germination, speed of germination, seedling growth, chlorophyll content and respiratory activity. After two weeks of exposure, the weed plants wilted. Out of the two monoterpenes, cineole was more toxic in causing injury to the weed.

Water Relations of Plants

Article

Jan 1985
SOIL SCI

P.J. Kramer

Sikkema J, de Bont JA & Poolman B. Mechanisms of membrane toxicity of hydrocarbons. Microbiol Rev59: 201-222

Article

Jul 1995
Microbiol Rev

Antifungal activity of volatile oil of Eucalyptus citriodora

Article

Jul 2002
FITOTERAPIA

The volatile oil extracted from the leaves of Eucalyptus citriodora showed a wide spectrum of antifungal activity.

Comparative Efficacy of Insect Repellents against Mosquito Bites

Article

Aug 2002
NEW ENGL J MED

The worldwide threat of arthropod-transmitted diseases, with their associated morbidity and mortality, underscores the need for effective insect repellents. Multiple chemical, botanical, and "alternative" repellent products are marketed to consumers. We sought to determine which products available in the United States provide reliable and prolonged complete protection from mosquito bites. We conducted studies involving 15 volunteers to test the relative efficacy of seven botanical insect repellents; four products containing N,N-diethyl-m-toluamide, now called N,N-diethyl-3-methylbenzamide (DEET); a repellent containing IR3535 (ethyl butylacetylaminopropionate); three repellent-impregnated wristbands; and a moisturizer that is commonly claimed to have repellent effects. These products were tested in a controlled laboratory environment in which the species of the mosquitoes, their age, their degree of hunger, the humidity, the temperature, and the light-dark cycle were all kept constant. DEET-based products provided complete protection for the longest duration. Higher concentrations of DEET provided longer-lasting protection. A formulation containing 23.8 percent DEET had a mean complete-protection time of 301.5 minutes. A soybean-oil-based repellent protected against mosquito bites for an average of 94.6 minutes. The IR3535-based repellent protected for an average of 22.9 minutes. All other botanical repellents we tested provided protection for a mean duration of less than 20 minutes. Repellent-impregnated wristbands offered no protection. Currently available non-DEET repellents do not provide protection for durations similar to those of DEET-based repellents and cannot be relied on to provide prolonged protection in environments where mosquito-borne diseases are a substantial threat.

Copper enzymes in isolated chloroplasts polyphenoloxidase in Beta vulgaris</REFATL

Article

Feb 1949
PLANT PHYSIOL

D. I. Arnon

Refinement of the Triphenyl Tetrazolium Chloride Method of Determining Cold Injury

Article

Nov 1967
PLANT PHYSIOL

The method of evaluating cold injury in woody plants by the use of triphenyl tetrazolium chloride has been refined to eliminate bias associated with visual differentiation between varying degrees of tetrazolium reduction and to predict tissue survival at a later date. An advantage of the method described here is that a small amount of tissue (50-100 mg) is required; this, therefore, allows for hardiness determinations at precise locations on the plant. The high correlation between cold injury and triphenyl tetrazolium chloride reduction may be due to cofactor and substrate limitations rather than inactivation of dehydrogenases.

Volatile Growth Inhibitors Produced by Aromatic Shrubs

Article

Feb 1964

Root growth of Cucumis and Avena seedlings is inhibited by volatile materials produced by leaves of Salvia leucophylla, S. apiana, and Artemisia californica. The toxic substance may be deposited when dew condenses on affected seedlings in the field.

Natural compounds from spices could replace potato sprouting inhibitors

Jan 1991
5

S F Vaughn

Vaughn S F. 1991. Natural compounds from spices could replace potato sprouting inhibitors. Industrial Bioprocessing 13:5.

Herbicide Handbook Supplement to Seventh Edition

K K Hatzios

Hatzios K K. (Ed). 1998. Herbicide Handbook Supplement to Seventh Edition, pp. 55–57.

Allelopathic Properties of Eucalyptus. MAB-DOEn Report Parthenium hysterophorus – a review

Jan 1990
105-149

R K Kohli
Kohli R K

Kohli R K. 1990. Allelopathic Properties of Eucalyptus. MAB-DOEn Report, New Delhi, India. Kohli R K, Rani D. 1994. Parthenium hysterophorus – a review. Research Bulletin (Science), Panjab University 44:105–149.

Essential oils as allelochemicals: research advances in Greece

Jan 1999
47-63

D Vokou

Vokou D. 1999. Essential oils as allelochemicals: research advances in Greece. In Allelopathy Update. Vol. 2. Basic and Applied Aspects, pp. 47-63. Ed. S S Narwal. New York: Science Publishers.

Water Relations of Plants Higher plant terpenoids: a phytocentric overview of their ecological roles

Jan 1983
1223-1280

P J Kramer

Kramer P J. 1983. Water Relations of Plants. Orlando, Florida: Academic Press, Inc. Langenheim J H. 1994. Higher plant terpenoids: a phytocentric overview of their ecological roles. Journal of Chemical Ecology 20:1223–1280.

Agrochemical sales flat in

Anon

Allelopathic Properties of Eucalyptus

R K Kohli

Parthenium hysterophorus– a review. Research Bulletin (Science)

Kohli R K
Rani D.

Leaf diffusibility changes of bean and sunflower plants treated with essential oil vapours

Jan 1986
119-128

M Polova
M Vicherkova

Polova M, Vicherkova M. 1986. Leaf diffusibility changes of bean and sunflower plants treated with essential oil vapours. Scripta Facultatis Scientiarum Naturalium Universitatis Purkynianae Brunensis (Biologia) 16:119-128.

Herbicide activity of volatile oils from Eucalypus citriodora against Parthenium hysterophorus

Abstract

No full-text available

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