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Allelopathic Potential of the Essential Oil of Wild Marigold (Tagetes minuta L.) Against Some Invasive Weeds
Abstract
Tagetes minuta is an aromatic plant native to Tropical America. It exhibits wide range of biological activity against insects, nematodes, microbes including medicinal properties. It also creates nuisance for agricultural land. This may be attributed to its allelopathic properties. Therefore, the present study investigated the allelopathic potential of volatile oil of T. minuta on other invasive weeds-Chenopodium murale L., Phalaris minor Retz. and Amaranthus viridis L. It was observed that the volatile oil of T. minuta significantly reduced the germination, growth, chlorophyll content and respiratory ability of recipient weeds in a dose dependent manner. Mitotic studies revealed a complete arrest of mitotic activity in cells of treated root tips of Allium cepa with various aberrations like distorted, trinucleolated and binucleated cells. Thus, it can be concluded that the volatile oil of T. minuta shows allelopathic potential on other plants and this property could be further explored for weed management.. 2015. Allelopathic potential of the essential oil of wild marigold (Tagetes minuta L.) against some invasive weeds. Journal of Environmental & Agricultural Sciences. 3:56-60.
... Rich phytochemistry of essential oil of T. minuta have led farmers to grow it under cultivation specially in drug growing areas of the world (Chalchat et al., 1995). Despite many reports of ethnobotanical and pharmacological uses of essential oil of T. minuta, very few reports have indicated its possible use in controlling weeds in agroecosystems or wastelands (Singh et al., 2003;Lopez et al., 2009;Arora et al., 2015Arora et al., , 2016. There is no report about the mode of application of EO of T. minuta for effective and eco-friendly weed management. ...
... Qualitative data pertaining to identification of relative amount of each constituent in essential oil of T. minuta was done by Gas Chromatography-Mass Spectrometry (GC-MS). Detailed procedure has been reported earlier (Arora et al., 2015). ...
... The oil was found rich in monoterpenes both hydrocarbon as well as oxygenated types. In another publication detailed composition of T. minuta EO has been published (Arora et al., 2015). cis-β-Ocimene and dihydrotagetone were the major components of oil. ...
Essential oil (EO) of Tagetes minuta L. extracted from aerial parts of plant through hydro-distillation was tested for its chemical composition by GC-MS. In order to explore the allelopathic potential of the oil, it was tested under laboratory conditions on a common agricultural weed Phalaris minor. The modes of oil application were volatile form (VB), solution form (SB) and oil mixed with agar-agar (AAB). Bioassay studies revealed a dose-dependent inhibitory effect of EO of T. minuta on growth of P. minor. Most effective mode of treatment was VB followed by AAB and minimum effect was observed in SB. Thus, volatile form of EO is best suitable for managing P. minor in agroecosystems.
... The results showed that EO significantly inhibited the early growth factors of A. retroflexus and C. album, and the growth responses were concentration-dependent. These findings are in agreement with the prior studies representing the phytotoxic activity of EOs (Arora et al., 2015;Scrivanti et al., 2003;Singh et al., 2009;Mutlu et al., 2010). The studied EO, which was rich in carvacrol, caused 64-96% reduction in the root and shoot growth of the two weed seedlings. ...
... reduced by increasing the concentration of NE when compared with the controls (Tables 4 and 5). This result is in agreement with the findings of Arora et al. (2015) and Kaur et al. (2010). Moreover, the EO compounds interfered with DNA synthesis in growing meristems, reduced the cell division in growing root tips, and led to growth inhibition (Romagni et al., 2000;Nishida et al., 2005). ...
... The greatest reduction (53%) in chlorophyll content was observed in C. album by 3000 μL.L −1 NE. Our findings are in agreement with previous reports regarding the negative effect of EO and monoterpenes on chlorophyll content (Arora et al., 2015;Ahuja et al., 2014Ahuja et al., , 2015Singh et al., 2002;Zhou and Yu, 2006;Kaur et al., 2011). Furthermore, EOs and their individual components might affect the photosynthetic performance of plants. ...
The aim of the present study was to obtain an oil/water (O/W) nanoemulsion (NE) containing garden savory (Satureja hortensis) essential oil (EO) and evaluating its herbicidal activity against Amaranthus retroflexus and Chenopodium album. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were employed to determine the chemical composition of the EO. Carvacrol (55.6%) and γ-terpinene (31.9%) were the major EO components. Low energy method was applied, allowing achievement of EO nanodroplets. The NE also presented low polydispersity, and the mean droplet was below 130 nm even after storage for 30 d. Laboratory tests showed that the NE at different concentrations (100, 200, 400, 800, and 1000 ) significantly (P≤0.05) reduced the germination indices and the seedling's growth in dose-response. The inhibitory effect was the greatest at 800 NE. Overall, root length was more inhibited as compared to shoot length. Post-emergence application of NE at different concentrations (1000, 2000, 3000, 4000 and 5000 of EO) on 2–4 true leaves' stage of the weeds caused significant (P≤0.05) decrease in the growth factors in dose-dependent manner. Complete lethality was observed by 4000 NE sprayed on the weeds. Spraying of NE significantly (P≤0.05) reduced chlorophyll content in the tested weeds. Increasing in relative electrolyte leakage (REL) 1 and 5 d after treatment represented significant cell membrane disruption and increased cell membrane permeability. Transmission electron microscope (TEM) pictures confirmed NE droplet size and demonstrated membrane destruction. The study approved that the NE of S. hortensis EO has herbicidal properties as it has high phytotoxic effect, and interferes with the germination, growth and physiological processes of the weeds. The production of NE from S. hortensis EO is a low energy method that offers a promising practical natural herbicide for weed control in organic agricultural systems.
... Allelopathy is the inhibitive/detrimental effect of one plant species on the germination, growth and metabolism of another plant species due to release of agrochemicals into the environment. Allelochemicals are mostly extracted from plant materials because their ability to synthesize aromatic secondary metabolites as phenolic acids, phenols, flavones, flavonoids, flavonols, saponins and coumarins, which accumulate in the cells of the epidermis of plant organs such as flowers, leaves, stems, roots, seeds and fruits in small quantities 9 12,13 . Rosemary essential oil inhibited germination percentage, root and seedling length in various weeds 14 . ...
... The oil showed herbicidal activity against the weeds Chenopodium murale, Phalaris minor and Amaranthus viridis and its seed germination response was dose-dependent 13 . T. minuta tissues might hinder with the germination of specialist species by delivering and discharging ocimenones. ...
Weeds cause higher reductions in crop yield than any other pest or disease; yet they remain underestimated in tropical agriculture. Controlling composite culture of weeds in the crop field is difficult. Continuous use of synthetic herbicides may have an adverse impact on human health and the agro-ecosystem. Natural products such as essential oils, plant extracts, allelochemicals, agricultural by-products and some microorganisms are being studied in this area since they are environmentally friendly and have low toxicity. Being ecologically stable, they may provide an alternative to synthetic herbicides. In this article, we document the research done across the world to establish medicinal and aromatic plants as source of bioherbicides for sustainable agricultural production.
... Extract and essential oil of T. minuta were found to have great allelopathic effect on seed germination of Lotus corniculata, and Lactuca sativa (113,114), callus induction and growth of Oryza sativa, Brassica campestris, Raphanus sativus and Sesamum indicum (115,116). Allelopathic capability of T. minuta essential oil against three obtrusive weeds: Chenopodium murale, Phalaris minor and Amaranthus viridis were studied by Arora et al. (117) and Amri et al. (118). It has been reported that essential oils and their constituents inhibited cell division and interfered with DNA synthesis in growing meristems, also enhanced rate of respiration which shows phytotoxic influence of the oil on recipient weeds (117). ...
... Allelopathic capability of T. minuta essential oil against three obtrusive weeds: Chenopodium murale, Phalaris minor and Amaranthus viridis were studied by Arora et al. (117) and Amri et al. (118). It has been reported that essential oils and their constituents inhibited cell division and interfered with DNA synthesis in growing meristems, also enhanced rate of respiration which shows phytotoxic influence of the oil on recipient weeds (117). T. minuta dry powder mixed with soil reduces the weed emergence and growth in rice grown under nursery conditions (10). ...
Wild marigold (Tagetes minuta L.) is a highly demanded aromatic plant, having great industrial value. Recently farmers are more interested in its cultivation and are opting it in their cropping system. Major constituents of its essential oil are β-ocimene, dihydrotagetone, tagetone, tagete-none, and limonene. The Current market demand for tagetes oil is increasing at a faster rate due to its large use in flavor and perfumery industry. Its oil and plant extract has potential bioactive and therapeutic properties. The Integration of this species in agricultural production systems still relies on thorough information and agronomic potential of this plant. Understanding its biology, chemistry, biological activity and agrotechnology will allow better utilization of this crop. Therefore, the published literature on research and development of tagetes crop for improvement in its yield and quality is compiled in this chapter which will fulfill the demand of various industries and improves the rural economy. ARTICLE HISTORY
... T. minuta oil also possesses therapeutic and antioxidant properties [19,20]; however, very few researchers have tested essential oil of this plant for weed management. Recently, we have reported allelopathic potential of T. minuta oil against Chenopodium murale L., Phalaris minor Retz., Amaranthus viridis L., and Cassia occidentalis L. [21,22] where oil was used in volatile form. However, for foliar or soil application, it has to be applied in solution form. ...
... In general, a dose-dependent type of relationship between oil concentrations and germinating parameters of all test plants was apparent, indicating greater inhibition with increase in concentration. Similar observations that essential oil exerts inhibitory effect were also made by several other workers [21][22][23][24][25][26][27][28][29]. Since essential oils are composed of monoterpenes and/or sesquiterpenes, thus their inhibitory effect may be contributed by all or few major constituents either synergistically or additively. ...
Objective: Tagetes minuta (Family Asteraceae) is an aromatic plant possessing volatile essential oil. T. minuta oil possesses medicinal and insecticidal properties as antiheminthic, nematicidal, bactericidal, antiviral, fungicidal, and insecticidal. However, it has been explored for herbicidal potential in very few reports. The aim of this study is to find out its allelopathic potential against common wasteland and agricultural weeds. Methods: The various agricultural and wasteland weeds were selected for laboratory growth studies. Oil was applied in solution form using an emulsifier. Results: Growth of all test weeds was inhibited by T. minuta oil; however, the effect was maximum in Amaranthus tricolor with complete inhibition at 1 μl/ml, and Echinochloa crus-galli was least affected with complete inhibition at 5 μl/ml concentration of T. minuta oil. Conclusion: T. minuta oil offers great potential for effective weed management in agricultural as well as wasteland areas. Keywords: Tagetes minuta, Essential oil, Allelopathy, Solution form, Wasteland, Agricultural Weeds.
... Allelopathy is generally recognized as an important ecological factor that determines the structure and composition of plant communities [80] . This phenomenon of certain plant species possessing the capability to affect surrounding plants has been widely documented and is currently being explored as a potential method of weed control and management [79,81] . Tagetes minuta essential oils and their principal components in the vapour phase were studied for their allelopathic activity on roots of Maize (Zea mays L.) [80] . ...
... Thus, the high phytotoxicity action of T. minuta EOs was attributed to its high content of ocimenone. In another study, the allelopathic potential of EOs of T. minuta against three invasive weeds: Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L. was investigated [81] . The results of the study established a concentration-dependent response in which volatile oils of T. minuta reduced germination in the three test weeds with maximum reduction observed in C. murale followed by P. minor and least in A. viridis. ...
Mexican marigold (Tagetes minuta L.) and its accruing products have a long worldwide history of human uses such as food, therapeutics and aromatherapy which are inherent in the plant's unique chemical composition and bioactivities. In the recent past, T. minuta essential oils (EOs) have received great attention in research, and their phytochemistry, bioactivities and uses remain the focus of considerable scientific studies. The interest in EOs is largely due to increased demand by consumers for natural-based products such as additives, drugs and pesticides, whose global acceptability and safety is highly regarded compared to synthetic products. The purpose of this review is to document the existing value addition and evidence-based multipurpose potential and considerations of T. minuta as a new generation crop as provided for by in-depth scientific studies of its EOs. Among the bioactivities and therapeutic properties attributed to T. minuta EOs include: antihelminthic, carminative, arthropod repellency, sedative, weedicidal, antiseptic, diaphoretic, spasmolytic, germicides, stomachic, antispasmodic, antiprotozoal, bactericidal, emmenagogue, nematicidal, insecticidal, fungicidal, antiviral and other microbicidal properties against a wide range of plant, human and animal pathogens, pests and parasites. Oil of T. minuta is therefore a potentially useful agent for protecting food crops on farm and in storage and livestock, thereby enhancing food security and improving human livelihoods. Nevertheless, increased value addition and the need for validation of traditionally claimed usages and applications of T. minuta EOs through in-depth scientific studies should be prioritized to globally position this plant as a new generation crop.
... Pradesh, India (Ramesh and Singh 2008), (Rathore, Walia, and Kumar 2018), (Arora et al. 2015),(A. Kumar et al. 2020);Haryana, India (Gulia et al. 2017); Palampur, India (Walia, Bhatt, and Kumar 2020); Hyderabad, India (Rao et al. 2006),(Kaul et al. 2005; Lucknow, India (Basal et al. 1999); New Delhi, India ("Ray et al 2008) ; Novi Sad, Serbia (Petrović et al. 2007) (Petrović et al. 2010); Bologna, Italy (Marotti et al. 2004);Hatay, Turkey (Bahadırlı 2020);Eskisehir, Turkey (Baser and Malyer 1996); Lublin, Poland,(Król 2012); Embu, Kenya (Mugao et al. 2020b); Tehran, Iran (Sefidkon et al. 2004) (Moghaddam, Omidbiagi, and Sefidkon 2007) (Babaei et al. 2021) (Saharkhiz et al. 2012); Tabriz, Iran(Bahram Mirshekari 2012); Shiraz, Iran (Negahban et al. 2013); Urmia,Iran (Amuamuha, Pirzad, and Hadi 2012) However, no study has been reported yet on the essential oil research of Bangladesh region marigold as per the authors' knowledge except a report on agronomic practices, relative profitability, and input-output relationship of marigold harvesting in Bangladesh ("Economics of Marigold Cultivation in Some" 2012). ...
... Similar findings were also recorded by many researchers (Arora et al., 2015;Prasad et al., 2016;Turker et al., 2008). The degree of inhibition was largely dependent on the concentration of the aqueous extracts . ...
The aim of this work was to evaluate phenolic profile, antioxidant capacity and allelopathic effects of six Ziziphyus spina-christi provenances in Saudi Arabia. Total phenols, flavonoids, tannins and antioxidant activity were evaluated. Total phenols, condensed tannins and total flavonoids were present at levels of 62.29 mg GAE/g DM, 16.69 mg CE/g DM and 15.45 µg mg QE/g DM, respectively. The high antioxidant activity (0.15 mg/ml) was noted in Mecca Road provenance. The highest germination, shoots and radicle lengths of tested species were observed in At-taif provenance. Z. spina-christi leaf extracts may be suggested in foods and pharmaceutical industries. Leaf extracts could also provide a natural herbicide with a positive impact on the environment. Provenance of Jizan, Northern Borders and Mecca Road were shown to be particularly effective in antioxidant capacity, while Provenance of Riyadh and Northern Borders shown to have the best allelopathic activity.
... and Chenopodium murale L., and Amaranthus viridis L. volatile essential oil from T. minuta significantly reduced the growth, germination, chlorophyll content, and respiratory ability of weeds in a dose-dependent manner. Due to the complete arrest of mitotic activity revealed in cells of treated root tips of Allium cepa, these were effective with various aberrations, such as binucleated, trinucleated, and distorted cells [95]. ...
The municipal authorities in developing nations face serious challenges in marigold flower garbage management. The primary issue is that they never are reused after prayers. Flower waste of Tagetes erecta, T. patula, and Calendula officinalis L. are commonly used for carotenoid and flavonoid extractions and, subsequently, used for incense stick and biogas production. Marigold plants are also used for phytoremediation during their growth stage. The lutein industry is booming due to its increasing market demand, expected to reach ~2121.2 billion tons by 2022, where marigolds are a major contributor globally. The process of isolating lutein from saponified marigold oleoresin yields a product with 70–85% purity. Lutein is a major xanthophyll (70–88%) of marigold petals, and a maximum of 21.23 mg/g of lutein was extracted. This review discusses the properties of selective marigold species, their compositions, and the extraction of different flavonoids and carotenoids, especially lutein. Moreover, different extraction methods of marigold lutein, the collection of marigold waste, and their subsequent utilization to derive several value-added products are discussed. Among physical treatments, ultrasonic-assisted extraction and enzymatic treatment with 5% solids loading were the maximum-yielding methods.
... For shrinking the dependence on the synthetic pesticides and maintaining the agroecosystems, allelopathy phenomenon as an ecologically safe method could be exploited in weed control with improving crop yields (Hegab et al. 2008. Allelopathic effect could be regarded as a sustainable pattern for biologically weed management (Arora et al. 2015) by liberating chemical compounds from different plant organs influencing adversely the growth of other plants (Delcour et al. 2015). Owing to the integration with aqueous plant water extracts, herbicide addition rate could be lowered with achieving distinctive efficacious weed control (Khan et al. 2012). ...
To reduce the use of herbicides in agriculture, there is an urgent need to look for cost-effective and environmentally friendly non-chemical methods to control weeds in field crops. Plant by-products could be exploited directly as plant residues or indirectly as plant extracts for weed control. Thus, the objective of this study was to evaluate the effectiveness of several plant wastes and extracts in controlling weeds of sugar beet (Beta vulgaris subsp. vulgaris) with enhancing yield and quality. Three weed control groups of twelve practices were examined. The first weed control group included three aqueous extract concentrations (15, 20, and 25%) of Plectranthus amboinicus L. The second weed control group involved six soil mulching plant materials [rice (Oryza sativa L.) straw, wheat (Triticum aestivum L.) hay, peanut (Arachis hypogaea L.) straw, mango (Mangifera indica L.) leaves, flax (Linum usitatissimum L.) meal, and soybean (Glycine max (L.) Merr.) meal], while the third group comprised of desmedipham/ethofumesate/lenacil/phenmedipham (DELP) herbicide 1.5 L ha−1 [desmedipham 70.5 g active ingredient (ai) ha−1 + ethomesufate 112.5 g ai ha−1 + lenacil 40.5 g ai ha−1 + phenmedipham 90 g ai ha−1], hoeing, and unweeded check. During a 2-year field trial (2019/20 and 2020/21), the 12 weed control treatments arranged in a randomized complete block design (RCBD) and replicated three times. Compared to the recommended applications (hoeing and herbicide), reduction averages of both seasons for total weeds biomass were 46.3–54.2%, 37.3–46.4%, and 23.0–34.4% due to rice straw, wheat hay, and mango leaves, respectively. Root and sugar yields of sugar beet divulged the highest values with hoeing in both seasons statistically equaling (P ≥ 0.05) rice straw and wheat hay for root yield and wheat hay for sugar yield in the first season. Except flax meal, all weeded treatments in the first season as well as mango leaves, wheat hay, peanut straw, and hoeing in the second one caused significant (P ≤ 0.05) reductions in sodium content of beet juice. Wheat hay, mango leaves, and hoeing in both seasons, in addition to rice straw, peanut straw, and herbicide in the first season, were the most efficient practices for improving sucrose % and extractable sugar %. Compared to hoeing, reductions in net return were –286.7 and –320.0 ($ ha−1) by percentage of 6.5 and 7.2, due to mulching soil by rice straw and wheat hay, respectively. Recycling the plant by-products such as wheat hay, rice straw, peanut straw, or mango leaves in the form of soil mulch could serve as safe and eco-friendly tools in weed control programs of sugar beet. The beneficial effect of mulching extended to enhance root and sugar yields with low impurities. Since the plant wastes are available in the farm, better revenues will be gained for sugar beet growers. Further investigations related to the use of plant extracts as natural herbicide should be performed to reach acceptable levels for weed control.
... Furthermore, there was no much significant effect on the radical length except for I. hirsuta that showed a significant difference when compared with the control at 10, 15, and 20%. This is corroborated with the study conducted by [31] that said seedling length was significantly reduced when compared with control except for lower concentrations as well as decrease in dry weight of seedling. Moreover, the degree of the inhabitation increased with the increasing concentration of the extracts. ...
The uses of paraquat chemicals as weedicide in agriculture soil have causes the loss of natural habitats, food, and pollution of environment, risk of human health, animals and contamination of water body. This research aimed to study the allelopathic effect of aqueous extract of Sesbania sesban (L.), Rhynchosia minima L, Indigofera hirsuta L, Tephrosia vogelli F and Crotalaria retusa L on seed germination and growth of Borreria stachydea (DC.) using in-vitro and in vivo methods at different concentrations 5%, 10%, 15% and 20%. From, the results obtained, the extracts of I. hirsuta L and S. sesban (L.) had higher inhibitory effect at 20% concentration, than that of T. vogelli F, Crotalaria retusa L. and R. minema L on growth parameters of B. stachydea (DC.) when compared with control. In laboratory, most toxic plant extract against B. stachydea (DC.) was S. sesban (L.). Therefore mixed extract of these plant could be used in management of weed in order to reduce the use of synthetics herbicides in agricultural land for the control of weeds. Farmers should allow these five species with allelopathic properties to growth closed to cultivated crops.
... Weeds as led to severe yield losses when uncontrolled, Korieocha (2014) reported 50 -100 % lost in cassava tuber yield while Iyagba (2010) revealed that, such a loss usually depends on the weed spectrum of the field. The suppression of weeds in an intercropping system may be through competition for growth resources or allelopathy (Arora et al., 2015). Cassavamaize intercrop is one of the effective means of suppressing arable weeds (Negash and Mulualem, 2014) although there is a need to establish the optimum plant density of intercrop components (Olorunmaiye et al.,2013) and apply recommended type and rate of fertilizer to enable a speedy canopy closure suitable for better weed suppression (Okeleye and Salawu, 1999). ...
... Also, Ajayi et al. (2014) observed that the essential oil constituent, carvacrol, 1-8-cineole and eugenol applied at 10 and 20 µl/L reduced cowpea seeds germination and seedling growth. Arora et al. (2015) who evaluated the allelopathic potential of the essential oil of Tagetes minuta l. against Chenopodium murale L., Phalaris minor Retz. and Amaranthus viridis L. and the result showed that the volatile oil of T. minuta significantly reduced the germination, growth, chlorophyll content and respiratory ability of recipient weeds in a dose dependent manner. ...
The use of synthetic insecticides in the control of stored product insect pests including Callosobruchus maculatus has led to the development of resistance and other undesirables side effects. Therefore, present study was conducted to evaluate the bioactivity of essential oils of coriander, fennel and sweet almond against C. maculatus (F.) on stored cowpea seeds. The bioassays used three dosages of each essential oil (2.0, 4.0 and 6.0 ml /100 g seed and the untreated control 0.0 g/100 g seed) at 27 ± 2°C and 45 ± 5% relative humidity (r.h.) to assess adult mortality, number of adult emergence, percentage seed damage, weight loss and germination. At 1 day after treatment (DAT), 100% adult mortality was observed at the highest dosage of coriander essential oils (6 ml/100 g) which was significantly (p < 0.05) different from the untreated control. Similar trends followed at 3 and 5 DAT. All the treatments significantly (p < 0.05) reduced F1, F2 adult emergence, seeds damage as well as weight loss compared to the untreated control. They also negatively affected germination of cowpea seeds. It is therefore concluded that essential oils of coriander, fennel and sweet almond could be used against Callosobruchus maculatus and can serve as alternative to synthetic insecticides.
... Also, Ajayi et al. (2014) observed that the essential oil constituent, carvacrol, 1-8-cineole and eugenol applied at 10 and 20 µl/L reduced cowpea seeds germination and seedling growth. Arora et al. (2015) who evaluated the allelopathic potential of the essential oil of Tagetes minuta l. against Chenopodium murale L., Phalaris minor Retz. and Amaranthus viridis L. and the result showed that the volatile oil of T. minuta significantly reduced the germination, growth, chlorophyll content and respiratory ability of recipient weeds in a dose dependent manner. ...
The use of synthetic insecticides in the control of stored product insect pests including Callosobruchus maculatus has led to the development of resistance and other undesirables side effects. Therefore, present study was conducted to evaluate the bioactivity of essential oils of coriander, fennel and sweet almond against C. maculatus (F.) on stored cowpea seeds. The bioassays used three dosages of each essential oil (2.0, 4.0 and 6.0 ml /100 g seed and the untreated control 0.0 g/100 g seed) at 27 ± 2°C and 45 ± 5% relative humidity (r.h.) to assess adult mortality, number of adult emergence, percentage seed damage, weight loss and germination. At 1 day after treatment (DAT), 100% adult mortality was observed at the highest dosage of coriander essential oils (6 ml/100 g) which was significantly (p < 0.05) different from the untreated control. Similar trends followed at 3 and 5 DAT. All the treatments significantly (p < 0.05) reduced F1, F2 adult emergence, seeds damage as well as weight loss compared to the untreated control. They also negatively affected germination of cowpea seeds. It is therefore concluded that essential oils of coriander, fennel and sweet almond could be used against Callosobruchus maculatus and can serve as alternative to synthetic insecticides.
... Weeds are one of the major limitations in the growth and development of young kiwifruit plants. Intercropping has proven to achieve weed control through competing for resources with weeds and intercrops may secrete allelochemicals to the detriment weed growth [41][42][43]. However, we did not assess the presence of weeds in our study, so this potential benefit of intercropping warrants further research. ...
Drought, low nutrition, and weeds have become the major limiting factors of young kiwifruit orchards. In this study, the effects of intercropping Vicia sativa L. on the moisture, microbe community, enzyme activity, and nutrients in rhizosphere soils of young kiwifruit plants and their growth were investigated. The results show that intercropping V. sativa could effectively enhance soil moisture by 1.39–1.47 folds compared with clean tillage. Moreover, intercropping V. sativa could significantly (p < 0.01) increase the microbial community, enzyme activity and nutrient of kiwifruit rhizosphere soils, and improve plant height, stem girth, leaf number, maximum leaf length, maximum leaf width, and chlorophyll content of young kiwifruit plants by 43.60%, 18.68%, 43.75%, 18.09%, 21.15%, and 67.57% compared to clean tillage, respectively. The moisture, microbial quantity, enzyme activity, and nutrients in rhizosphere soils of young kiwifruit plants exhibited good correlations with their plant height, stem girth, leaf number, maximum leaf length, maximum leaf width, and chlorophyll content. This study highlights that intercropping V. sativa in young kiwifruit orchard can be used as an effective, labor-saving, economical and sustainable practice to improve the moisture, microbial community, enzyme activity, and nutrient of soils, and enhance kiwifruit plant growth and control weeds.
... In this regard, allelopathy as a natural and an environment-friendly approach for weed control can improve crop yields, decrease the use of synthetic pesticides, and maintain the ecosystems (Hegab et al. 2008). Allelopathy presents a significant and sustainable tactic for biologically weed management (Arora et al. 2015) by release of chemical substances from various plant parts which ultimately affect the normal growth of other plants (Delcour et al. 2015). Herbicide application rate can be reduced by up to 68%, in combination with sorghum water extracts, for efficient weed control in maize (Khan et al. 2012). ...
Two field trials were conducted in 2018 and 2019 to develop practical and economically efficient weed control programs in corn. The experiment included six treatments (cowpea, rice straw, sorghum extract, hoeing, foramsulfuron herbicide and weedy check). The treatments were arranged in randomized complete block design with four replicates. Findings showed that reduction in total weed number was evident with application of hoeing, cowpea and rice straw in 2018 and 2019 seasons, in addition to foramsulfuron herbicide and sorghum extract in 2019. Cowpea, hoeing, foramsulfuron herbicide and rice straw recorded higher reduction in dry biomass of grassy weeds in both seasons. Reductions in N, P and K uptake by weeds because of rice straw and cowpea treatments were similar to hoeing treatment in both seasons. The increases in ear grain weight and grain yield ha−1 due to cowpea and hoeing treatments were similar to rice straw one. In 2019 season, cowpea treatment was the superior practice for improving N, P and K uptake of maize, significantly leveling hoeing for K uptake. The values of gross returns and benefit/cost ratio of cowpea and sorghum extract, respectively, were higher than rice straw application. In conclusion, cowpea as a live mulch achieved acceptable weed control in maize by reducing weeds growth and lowering their ability to deplete the soil nutrients. Also, cowpea treatment improves growth and yield of maize with better utilization of nutrients. Thus, cowpea could be exploited as an eco-friendly method of weed management programs in maize cultivation.
... The lupeol content in M. eriocarpum extracts (0.23 to 2.31 ppm, Table 2) may have an influence on phytotoxic activities of extracts. At low concentrations it can promote cell growth by increasing the efficiency of enzymes and proteins; but at high concentrations, it can hyperpolarize membranes, altering the functioning of ATP pumps, promoting toxicity to the cells and causing growth reduction (Arora et al., 2015;de Martino et al., 2012). Inhibition of root growth and lateral root development may be directly related to the presence of lupeol, which in turn, may modulate auxin transport by altering membrane polarization patterns, and promoting the cells homeostasis of the root tissue. ...
... In brief, solution of 0.6% TTC was prepared bydissolve 0.6 g of TTC powder 100 ml of 0.5 mol -1 phosphate buffer (pH 7.8) at room temperature then sterilized through 0.22 µm filter and stored at −20°C until use. [12] Fresh samples of yeast cells were harvested using suction filtration and the staining procedures were done according to Vadivelan & Venkateswaran (2014) method with some modification using methanol instead of ethyl acetate. The staining level was quantified by measuring the absorbance of TF in the methanol solvent at wavelength 485nm. ...
Polyunsaturated fatty acids (PUFAs) play critical roles in human diets as well as in the prevention and control of several chronic diseases and for improvement of heart and brain functions, so its demand is growing. A ten yeast isolates were isolated from different marine habitats. The ability of these isolates to accumulate intracellular PUFAs was primary screened using Nile red and further screened using Triphenyltetrazolium chloride (TTC) stain at an absorbance of 485 nm. Amongst these isolates, four yeast isolates (namely D1, E2, G2, and W6) were exhibited the best results for PUFAs production. The E2 and W6 isolates showed higher lipid accumulation than G2 and D1 isolates with percent between 25 to more than 35% of the cell area with the Nile red with staining degree of 1.43, 1.30, 1.20, and 1.12, with the TTC dye, respectively. When the isolates were cultured on YPD medium at 25°C, isolate E2 yielded 29.3% lipid per dry biomass, while isolates W6 yielded 26.2%, G2 yielded 25.6%, and D1 yielded 23.4%. These isolates were identified based on phenotypic and genotypic characteristics as Candida parapsilosis E2, Candida parapsilosis D1, Pichia kuriavzevii W6, and Meyerozyma guilliermondii G2. Production of PUFAs was conducted under nitrogen-limited conditions using a shake flask technique. The fatty acids profile analysis showed that the lipid extracted from these strains contained oleic acid (18:1), linoleic acid (18:2), and palmitic acid (C16:0) as the major intracellular fatty acids produced that accounted for 90% of total lipids. Also, these strains displayed (27-32%) saturated fatty acids and produced a significant amount of unsaturated fatty acids ranged between 68 to 73 % of the total fatty acids make them a sustainable source for single-cell oil productionas well as pharmaceutical and nutritional industries.
... Proprio in Italia, il servizio sanitario è caratterizzato da uno dei più alti tassi di mancanza di personale (Pisanti et al., 2011) e da un'alta frequenza di cambio turno (Hasselhorn, Tackenberg e Peter, 2004), nonché da livelli di retribuzione inferiori rispetto agli standard europei (Arora et al., 2015). Inoltre, l'assistenza infermieristica riveste spesso un ruolo secondario nel contesto italiano, dove l'esperienza degli infermieri non viene pienamente riconosciuta in termini di capacità e autonomia. ...
... In fact, 56 % of the aliens recorded were herbs and as alluded to above there were very few (15 %) of the alien species recorded in this study were trees. The reasons for the dominance of these species are similar to those made for species that were most frequent across sites; for example, T. minuata has allelopathic properties (Arora et al., 2015), R. crispus has very high seed production, multiple flowering times in one year, quick establishment from seed, high germination rates, and can regenerate vegetatively ([viz. cuttings] Pino et al., 1995) and sexually (Pérez-Fernández et al., 2019). ...
Urban natural green spaces are becoming increasingly impacted by anthropogenic disturbances, promoting alien plant invasions. Using a rapidly developing city in South Africa as a case study, we related distribution, composition, and ordering of alien plant species to environmental and anthropogenic factors to identify drivers of invasiveness. Vegetation surveys were used to identify and quantify (in terms of composition and density) alien species within 30 natural green spaces. Floristic characteristics were then related to levels of non-natural disturbance and selected abiotic parameters. Based on the relationships observed, selected floristic parameters were used to develop an Alien Invasive Index to identify ‘invasive alien hotspots’. Collectively, 80 alien plant species (from 30 families) were found, 35 of which are invasive. The most speciose families were Asteraceae > Fabaceae > Verbenaceae. Their representatives, specifically the invasive shrubs Lantana camara (Verbenaceae) and Chromolaena odorata (Asteraceae) and alien herbs Conyza sumatrensis, Bidens pilosa and Tagetes minuata (Asteraceae) were also the most dominant in terms of frequency across sites and density. A Principal Component Analysis showed invasive alien plant species composition to be most strongly related to level of disturbance, followed by distance to informal settlement and soil moisture content. The Alien Invasive Index could discriminate between sites with low and high levels of invasiveness, and its suitability was validated by the fact that sites with very high index values were in close proximity to informal settlements. The study demonstrates the value of combining classical in situ vegetation surveys and overlay analysis using Geographic Information System for prioritising green spaces and alien species for management in cities that are limited in terms of financial resources.
... Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds-Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. ...
The allelopathic plants have been recommended as a suitable alternative for weed control under sustainable agriculture (Dahiya, Kumar, Khedwal, & Jakhar, 2017). Allelopathic plants smother weeds in the field following crop rotation (Dwivedi, Shrivastava, Singh, & Lakpale, 2012), cover or smother crops (Ch, Sturm, Varnholt, Walker, & Gerhards, 2016; Sturm, Peteinatos, & Gerhards, 2018), intercropping (Dhungana, Kim, Adhikari, Kim, & Shin, 2019), mulching (Abbas, Nadeem, Tanveer, Farooq, & Zohaib, 2016; Mabele & Ndong’a, 2019), and water extracts of allelopathic crop (Iqbal, Khaliq, & Cheema, 2019; Shahbaz, Sohail, Faisal, & Muhammad, 2018). The repressive effect of various allelochemicals in crops and trees is mainly ascribed to obstructed physiological and metabolic processes of a plant that has been used directly and indirectly for weed management (Cheng & Cheng, 2015; Farooq, Jabran, Cheema, Wahid, & Siddique, 2011). Allelochemical utilization for restricting weed growth is a realistic substitute for manufactured herbicides that do not have any harmful impacts (Bhadoria, 2011). Allelopathy is a new method offering numerous answers for the diminishing food accessibility under increasing worldwide population.
... Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds-Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. ...
The biological invasion may discover its root into the marvels of allelopathy, the allelochemicals produced by the plants as a mean of their defense mechanism has turned out to be hindering to the growth of its native plants yet not to their coexisting species due to their adaptive capability (Callaway & Ridenour, 2004). In fact, allelopathy has been proposed as an outcome of long-term coevolution within established plant communities and may demonstrate considerable harmful impact on the newly introduced species (Mallik & Pellissier, 2000). Plant secondary metabolites can influence the ecological processes and structures and combat against the natural foes and competing plants, allelopathy may serve as a valuable strategy (Prince & Pohnert, 2010).
... Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds-Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. ...
Asteraceae consists of 8–10% of angiosperm species, around 1600–1700 genera with 24,000 species (Funk, Susanna, Steussy, & Robinson, 2009). Several plants in the Asteraceae family, especially chromolaena odorata, Helianthus annuus, and Tithonia diversifolia (of which remnants of Ageratum conyzoides, Vernonia amygdalina, and Artemisia annua) are revealed to contain huge amounts of allelochemicals, especially in their leaves, reducing the growth of various plants (Eze & Gill, 1992). Parthenium (Parthenium hysterophorus L.), commonly known as congress grass, carrot weed, ragweed Parthenium, is an invasive poisonous herbaceous annual weed of this family. It decreases pasture productivity, affects livestock health, human health and activities, alters ecology and biodiversity, and competes with crop plants for available environmental resources thereby causing enormous yield loss. Parthenin is revealed to be the principal constituent of this plant which accounts for its allelopathy (Mawal, Shahnawaz, Sangale, & Ade, 2015). Netsere (2015) noticed the allelopathic effect of the whole plant of Parthenium on germination and growth of maize and sorghum. Similarly, the powder extract of Parthenium hysterophorus reduced the germination rate and growth of wheat plants (Anwar et al., 2016). Sorecha and Bayissa (2017) showed the allelopathic effects of different doses of aqueous extracts of leaf, stem, and root aqueous extracts of Parthenium on germination and vegetative growth of peanut and soybean. The allelopathic impact of Parthenium hysterophorus extract on the onion meristematic cell influenced mitotic depression leading to chromosomal deformity such as fragments, stickiness nuclear vacuolation, bridge, laggards, and micronuclei. The reduction of DNA content by Parthenium leads to alteration of normal metabolic activity which is a potential threat to genomic balance (Sinha, 2009). Leaf extract of Parthenium hysterophorus was reported to inhibit the germination rate and root length of Cicer arietinum (Shikha & Jha, 2016). Reported that Parthenium hysterophorus aqueous extract induced pollen sterility in Vicia faba. Observed that the acetone leaf extract of Parthenium hysterophorus inhibited germination and decreased root and shoot length of Cyamopsis tetragonoloba. Siyar et al. (2018) reported that the aqueous extract of leaves, stems, and roots of two weeds of Asteraceae (Artemisia annua and Taraxicum officinalis) had an inhibitory effect on seed germination of wheat and maize, where Artemisia annua proved more phytotoxic than Taraxicum officinalis. Kamal (2011) observed that the allelochemicals released by sunflower hampered germination and decreased the shoot length, root length, fresh weight, dry weight, chlorophyll contents and also reduced the level of hormones, GA, IAA in wheat. Leachate of Achillea biebersteinii was observed to negatively affect percentage and rate of germination and radical and shoot length of pepper. Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds—Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. Similarly aqueous and methanolic extract of Tithonia diversifolia significantly reduced seed germination, seedling growth, and the biochemical parameters and growth of Vigna unguiculata (Oyeniyi, Odekanyin, Kuku, & Otusanya, 2016).
... Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds-Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. ...
Allelopathy could be characterized as “an imperative component of plant impedance interceded by the addition of secondary metabolites produced by plants into the soil rhizosphere” (Weston, 2005). These secondary metabolites are typically exuded into the rhizosphere and affect the development of plants that are growing in the vicinity of allelopathic plants (Akemo, Regnier, & Bennett, 2000). Chemical compounds that inflict allelopathic impacts are called allelochemicals or allelochemics, which are by and large considered to be those chemical groups, for example, alkaloids, flavonoids, glucosinolates, phenolics and terpenoids (Reigosa, Souto, & Gonz, 1999). Natural products recognized with allelopathic potential have been classified into the following groups: (a) cytotoxic gases, (b) organic acids, (c) aromatic acids, (d) simple unsaturated lactones, (e) coumarins, (f) quinones, (g) flavonoids, (h) tannins, (i) alkaloids, and (j) terpenoids and steroids (Mushtaq & Siddiqui, 2018). Allelopathy has been well documented for many great years (Rice, 1984), however, the understanding of the mechanisms of the mode of action of allelochemicals stays darken (Mohamadi & Rajaie, 2009). Several biosynthetic pathways are responsible for the production of the various classes of these chemical compounds, though they are not necessary for primary processes of growth and reproduction for the allelopathic species (Pagare, Bhatia, Tripathi, Pagare, & Bansal, 2015). However, these compounds can influence plant development indirectly by modifying the interspecific competition for the plants in association (Abhilasha, Quintana, Vivanco, & Joshi, 2008). A wide array of these compounds are known today, however, just a limited number has been recognized as allelochemicals (Mushtaq & Siddiqui, 2018; Rice, 1984). Allelochemicals are predominantly present throughout the plant including leaves, stems, roots, rhizomes, inflorescence, pollen, fruits and seeds (An, Pratley, & Haig, 1998). The production of allelochemicals in a plant species may vary spatially and over time scale; Singh, Jhaldiyal, and Kumar (2009) found foliar and leaf litter leachates of Eucalyptus species more lethal than its bark leachates to some commercial crops.
... Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds-Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. ...
Weeds are undesired plants that are of no economical use and are hard to manage by farmers. Weeds affect the growth and development of crops and therefore limit their productivity (Ani, Onu, Okoro, & Uguru, 2018). In the agricultural system, weeds compete with crop plants resulting in the loss of their yield (Gaba, Reboud, & Fried, 2016). They limit the accessibility of light, moisture, space to crops and deteriorate their quality (Guglielmini, Verdú, & Satorre, 2017). In view of these features, it has become necessary to check its growth. However, with the beginning of agriculture, the most prominent weed control approaches include an application of herbicides and hand/motorized weeding (Jabran, Mahajan, Sardana, & Chauhan, 2015; Young, Meyer, & Woldt, 2014). These approaches have a remarkable contribution to the improvement of crop production; but various hurdles are associated with them, as well. However, wide utilization of herbicides to check the growth of weeds has led to severe ecological and environmental problems like herbicide resistance, a shift in weed flora, and environmental pollution and health hazards due to their toxic residues in soil, water, and food chain. The harmful effect of commercial herbicides makes it suitable to explore various other weed management alternatives (Nirmal Kumar, Amb, & Bora, 2010) and allelopathy seems to be one of the options (Rawat, Maikhuri, Bahuguna, Jha, & Phondani, 2017). Allelopathy is an eco-friendly weed management tool, which is practiced to combat the impacts of environmental pollution. Allelopathy is a chemical method that allows the plant to compete for a narrow range of resources (Gioria & Osborne, 2014).
... Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds-Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. ...
Molisch (1937) derived allelopathy from the two Greek words: allelon (which means ‘of each other’) and pathos (which means ‘to suffer’). Allelobiogenesis or allelopathy characterized by the combination of both biotic and abiotic stresses actuated by donor plants on recipient plants. As per the modern literature, the term allelopathy is an organic chemical interceded negative impedance between plants or microorganisms through its direct or indirect influence (De Albuquerque et al., 2011; Rice, 1984; Willis, 2000; Yang et al., 2011).
... Due to environment-friendly and sustainable approach, crop allelopathy is gaining attention of the weed researchers worldwide (Fragasso et al., 2013;Jabran et al., 2015). It can also eliminate the problems raised by synthetic chemicals (Duke, 2010;Arora et al., 2015;Cheng and Cheng, 2015;Yazlik and Uremis, 2016). Sustainable agriculture demands the execution of economically feasible and environment-friendly techniques to control weeds. ...
Dry land plants owing to their capability to grow under stressful environment have shown higher allelopathic potential as compared to cultivated plants. An experiment was conducted to investigate the herbicidal potential of aqueous extracts of four dry land plants viz. fruit and vine of Citrullus colocynthis, and above ground parts of Rhazya stricta; Crotalaria burhia and Calligonum polygonoides, with four concentrations (25, 50, 75 and 100%) of initially prepared extracts against Lathyrus aphaca, a common weed of wheat in the studied region. These plants were collected from dry land area (30.03° N and 70.38° E, 129 m above sea level, almost desert conditions) of Dera Ghazi Khan, Punjab, Pakistan. All the four plants exhibited pronounced herbicidal potential with 9 to 91% suppression of different parameters in L. aphaca). Maximum inhibition was recorded in germination (36-91%). Significant suppression in leaf count (9-65%), shoot length (12-59%), root length (4-62%), shoot fresh weight (17-71%), root fresh weight (10-60%), shoot dry weight (15-72%), root dry weight (13-64%), and nodule numbers (34-89%) was also observed. The highest inhibition was exhibited by R. stricta followed by C. colocynthis: fruit. However, in case of nodulation maximum suppression was produced by C. burhia extract. Least suppressant activity was observed for the C. polygonides extract. These results encourage the potential use of locally available dry land plants possessing strong allelochemical properties for nonchemical control of weeds ultimately reducing reliance on chemical control.
... Allelopathy refers to the harmful effects of secondary metabolites produced by plants on the growth and development of other organisms (Hussain et al. 2017). A vast number of researches have reported Asteraceae plants to be a source of allelochemical compounds, such as phenolic acids and terpenes (Batish et al. 2007; Khan and Khan 2010;Shafique et al. 2011;Arora et al. 2015;Wichittrakarn 2015). The allelochemical phenol inhibits plant growth by altering cell membrane permeability. ...
Respatie. D. W, Yudono P, Purwantoro A, Trisyono Y.A. 2019. The potential of Cosmos sulphureus flower extract as a bioherbicide for Cyperus rotundus. Biodiversitas 20: 3568-3574. Cosmos (Cosmos sulphureus Cav.) flower is recognized as natural source of bioherbicide compounds for several weeds. The purple nutsedge (Cyperus rotundus L.) is an important weed, and this research was aimed to determine the effects of cosmos flower extract on this weed. Dried cosmos flowers were threshed and extracted using maceration method with 70% alcohol. The experiment was conducted in the greenhouse using a completely randomized design (CRD) with three replications. Purple nutsedge tubers were planted in polybags and treated with cosmos flower extract applicated once to three times with 300 mL polybag-1 at the concentration of 40%. Different levels of inhibitions on purple nutsedge growth were observed at 30 and 60 days after sowing (DAS) due to the presence of gallic acid in the extract. Growth parameters for purple nutsedge were analyzed using Analysis of Variance (ANOVA) and followed by Least Significant Differences (LSD) at α=0.05. Significant reductions in the number of mother shoots, daughter shoots, and roots, length of mother leaves, length of rhizomes, root, and total leaf area of the purple nutsedge treated with the cosmos flower extract at 30 DAS compared to those in the control. A significant reduction was also observed in foliage dry weight, underground organs dry weight, and total dry weight of purple nutsedge. The three application times yielded maximum inhibition. In addition, these treatments reduced N, P, and K content, chlorophyll content, and photosynthesis rates at 30 DAS. These results suggest that cosmos flower extract has the potential for controlling purple nutsedge.
... Allelopathy refers to the harmful effects of secondary metabolites produced by plants on the growth and development of other organisms (Hussain et al. 2017). A vast number of researches have reported Asteraceae plants to be a source of allelochemical compounds, such as phenolic acids and terpenes (Batish et al. 2007; Khan and Khan 2010;Shafique et al. 2011;Arora et al. 2015;Wichittrakarn 2015). The allelochemical phenol inhibits plant growth by altering cell membrane permeability. ...
The secondary metabolites of Cosmos sulphureus Cav. are dominated by phenolic acids which functioned as allelochemicals. This research aimed to determine C. sulphureus. extracts effects and the optimum concentration on soybean germination and early seedling growth. C. sulphureus root, stem, leaf and flower aqueous extracts were assayed at 1, 5, and 10% and total phenols were quantified. Results showed aqueous extracts from all organs and all concentrations inhibited soybean seed germination and seedling growth. The degree of inhibition correlated positively to extract concentrations. Toxicity of C. sulphureus extracts varied based on plant part and was related to phenolic acid content, with toxicity by flower demonstrating the highest toxicity followed by leaf, stem and root. The flower extract had the highest phenolic acid content (14.96%). Further works intended to specify and verify the allelochemicals produced by this plant are still required.
... Santos et al., [124] have worked out the phytochemical and allelopathic evaluation of Tagetes erecta and Tagetes patula and on the basis of phytotoxic compounds present in them, their use in the management of organic agriculture particularly in vegetables have been suggested. The volatile oil from Tagetes minuta [125]. Both oil and cis-β-ocimene were strongly allelopathic against Cassia occidentalis L., a common wasteland weed but the effect of cis-β-ocimene was greater in comparison to oil [126] and maximum effect was seen on Amaranthus tricolor with complete inhibition at 1 μl/ml, whereas, Echinochloa crus-galli was least affected (amongst the tested plants) with complete inhibition at 5 μl/ml concentration [127]. ...
Abstract
Importance of medicinal plants to health care has been great and herbal
preparations are being produced at industrial scale particularly in developing
countries. The plant products obtained have a long history of use in
therapeutics, aromatherapy and food depending on the chemical constituents
and their bioactivity. In the recent past, marigolds have received a great
attention in scientific research, because of their multiple use and also the
information available about their phytochemistry and bioactivity. Tagetes
species commonly known as marigold is native to Mexico, being used for
medicinal and ornamental purposes. The plant is useful due to its unique
phytoconstituents for a range of diseases and disorders and is reportedly
effective against piles, kidney troubles, muscular pain, ulcers and wound
healing and the flowers are helpful in fever, stomach and liver complaints
and also in eye diseases. In India, marigold is also extensively used on religious
and social occasions such as in the beautification of mandaps and
pooja places; offerings at temples; marriage decorations and landscape
planning due to variable size and colour of its flower. Present review is an
effort to bring together the different strategies developed for the growth and
cultivation of marigold, its ecophysiological and remediation relevance under
a variety of environmental conditions and possible allelopathic potential.
It includes reports on pharmacological aspects like antibacterial, antifungal,
larvicidal, hepatoprotective, insecticidal, mosquitocidal, nematicidal,
wound healing, antioxidant, anticancer and antidiabetic properties/
activity of Tagetes .
... Similarly. among innovative techniques for crop management, allelopathy offers a unique and eco-friendly approach for weed management and growth regulation (Arora et al., 2015). Allelopathy involves the synthesis and release of bioactive chemical compounds that affect the growth and development of neighboring plants (Khan et al., 2014;Safdar et al., 2014). ...
Three-year field studies were undertaken at Agricultural Research Institute, Dera Ismail Khan, Khyber Pakhtunkhwa Province, Pakistan from 2010-11 to 2012-2013 with the aim of assessing the efficacy of different management techniques on weed growth and yield of chickpea under rain-fed conditions on residual moisture of a previous rice crop. Treatments of the experiment consisted of recommended full and half doses of three herbicides, i.e., Stomp 330E, Dual Gold 960EC and Isoproturon 500EW and the plant extract of Parthenium hysterophorus. Hand weeding treatment was kept as positive control whereas weedy check was included as negative control treatment. The experiment was laid out in a Completely Randomized Block (CRB) design replicated thrice. Parameters of the investigation were weed density, fresh weed biomass, chickpea growth, biological yield and seed yield. The data revealed that the full dose of Stomp 330E proved superior in terms of weed suppression by giving only 84, 69 and 55 weeds m-2 as compared to weedy check for the years 2010-11, 2011-12 and 2012-13, respectively. Likewise, the highest plant height and seed yield were also recorded for Stomp 330E (full dose) during the entire study, which was statistically at par with hand weeding. However, there was a reduction in overall chickpea yield during the second and third years of experimentation resulting from lower average rainfall. The extract of P. hysterophorus followed Stomp 330E in weed suppression, enhancing plant height as well as biological yield and seed yield. Moreover, the result also shows statistically similar results of the extract of P. hysterophorus for all other tested treatments. Based on the findings of the present research, it was found that herbicides and hand weeding showed superior results in terms of all tested parameters. However, both approaches are non-judicious: hand weeding is laborious while herbicides may cause environmental pollution, hence the herbicidal potential of P. hysterophorus needs to be encouraged in order to achieve sustainable weed management and high yield in an eco-friendly manner.
... For controlling weeds, synthetic chemicals (weedicides) are used which possess negative effect on human health and cause environmental pollution (Dallali et al., 2017) that augments to develop alternate weed management strategies (Thi et al., 2008). Allelopathy offers an important strategy for biological weed management (Arora et al., 2015) by production and release of chemical substances from leaves, flowers, seeds, stems or roots of plants which ultimately affect growth and development of other plants (Delcour et al., 2015). The most auspicious scheme to replace synthetic herbicides is to use environmental friendly natural chemical plant products. ...
The experiment was designed to study allelopathic effect of Rhazya stricta Decne. against selected weeds of wheat crop by using aqueous, hexane and methanolic extracts on filter paper and soil. The germination percentage, radicle length and plumule length were observed. The results revealed that R. stricta methanolic extract showed the highest degree of seed germination percentage inhibition of C. album, P. minor and R. dentatus with 47%, 43% and 42%, respectively in soil, and minimum germination for C. album (53%). The same extract caused significant radical length reduction of R. dentatus and A. fatua
measuring 51% and 50%, respectively. The highest degree of inhibition in plumule length was measured for A. fatua and R. dentatus with 55% and 34%, respectively by R. stricta methanolic extract. Based on the results, it can be concluded that R. stricta showed good allelopathic activity that may be used in future herbicide screening program to launch in the market.
... Allelopathic weed control may be applied as a single strategy in certain cropping systems, such as organic farming. Under allelopathic weed control, allelopathic potential of crops is manipulated in such a way that allelochemicals from these crops reduce weed competition (Qasem and Foy, 2001;Arora et al., 2015). The living plants or dead materials express allelopathic activity through allelochemicals exudation. ...
Allelochemicals also known as allelopathins/allelotoxins/phytotoxins are plant
secondary metabolites that interfere with growth of neighboring phytodiversity. The release
of such chemicals by plants in the naïve introduced range is one of the widely accepted
mechanisms of invasion presented as “Novel Weapons Hypothesis”. Recent advances in
plant allelopathy suggest the potential of such toxic compounds to replace synthetic
pesticides. Literature supports better results of various extracts from invasive plants against
different weeds. These chemicals could play effective roles in weed control providing better
alternatives to synthetic chemical herbicides, thereby reducing the risk of environmental
pollution. Application of allelochemicals at low concentrations at the fields can be a costeffective and efficient way to inhibit growth of undesired plants and enhance crop
productivity. We here, after extensive data research enlisted putative allelotoxins isolated
from invader plants and suggest further research on herbicidal and pesticidal activities of
these compounds to promote the idea “weed control through weeds”. This data presentation
supports the novel weapons hypothesis as well as will open doors for strategic research for
development of natural agrochemicals.
... Other terms, such as weeds and naturalized species, aiming to classify species related to their plant invasion ecology similarly often refer to a range of definitions which are overlapping in many cases (e.g. DiTomaso 2014; Abe et al. 2015;Arora et al. 2015). To date, there are no widely accepted conventional definitions of the different terms in use in the field. ...
The water hyacinth (Eichhornia crassipes) is one of the top ten most invasive aquatic plant species in the world. Due to its worldwide distribution, the plant has caused tremendous damage on ecosystems and human livelihoods alike. These negative impacts are especially problematic for developing countries such as Madagascar. Considering the weak economic situation of the country, using water hyacinth to generate economic profits remains the last option to manage the species. We investigated the use of water hyacinth at Lake Alaotra, the largest lake in the country. This lake and the surrounding area are of great ecological and economic relevance for Madagascar. However, the isolation of the region and poverty limit water hyacinth use only to alternatives suitable to the weak local infrastructure. The goal of this research is firstly to identify suitable water hyacinth use options according to the local conditions and to compare them with the locally used raw materials. The first part of this research identified drivers and barriers for using water hyacinth in the region according to the prevailing socioeconomic conditions. It identified especially the use of water hyacinth as raw material for fertilizers and handicrafts as suitable alternatives for Lake Alaotra. Within the second phase, water hyacinth handicrafts were produced and compared with the predominantly used traditional papyrus handicrafts regarding production path and related costs. It was found that assembling water hyacinth handicrafts was easier and faster and they could be sold at three times the sale prices of the traditional papyrus handicrafts. Within the last part, fertilizers based on water hyacinth (composts, green manure and ash) were locally produced and compared with the commonly used agricultural fertilizers NPK and cow dung. This was done by conducting a growth experiment with Chinese cabbage, a common fast-growing vegetable in the region. Additionally, the production and transportation costs of each type of fertilizer were also taken into account. The results showed high biomass gain of cabbage grown with water hyacinth composts which was also proved be cheaper than using NPK and cow dung. All in all, this research demonstrated the efficiency of water hyacinth use as compost and handicraft as a new source of income for the Alaotra region. However, the poverty and high vulnerability of the local population must be considered along the process for a successful implementation of water hyacinth use at Lake Alaotra. A participatory approach and by offering financial insurance to the farmers during the implementation phase could encourage them to test water hyacinth compost on their own fields. Due to the various external factors influencing the marketing of water hyacinth handicrafts, an intensive and sustained supervision should be provided to the craftswomen.
... Taban et al. (2013) reported that EOs of several Satureja species reduced shoot and root elongation in tested weed and tomato. Likewise, other authors mentioned that EOs of Rosemary and Wild marigold prevented shoot and root growth in several weed species (Arora et al., 2015;Alipour and Saharkhiz, 2016). Additionally, our findings showed that EOs concentrations had greater inhibitory effect on seedling growth rather than seed germination in B. tectorum and tomato. ...
Essential oils (EOs) composition of Rosmarinus officinalis L., Satureja hortensis L. and Laurus nobilis were analyzed by GC and GC–MS instrument. Then phytotoxic activities of mentioned EOs and a combination of R. officinalis and L. nobilis EOs (R+L) were evaluated against germination and growth of two weeds species, A. retroflexus (dicot), B. tectorum (monocot) and tomato. Applied EOs strongly inhibited the germination and seedling growth of the tested species, in a dose dependent manner with A. retroflexus being significantly more sensitive than others. Indeed, at 400 μL.L−1μL.L−1 EO of R. officinalis, germination of A. retroflexus decreased 91.3%, while for the same dose, germination and seedling growth of B. tectorum and tomato were reduced by 56.7% and 26.7%, respectively, compared with control. R. officinalis EO caused the most germination inhibitory for A. retroflexus and tomato while B. tectorum germination was well inhibited by S. hortensis EO. Seedling growth were also affected by EO application in a dose response manner. A. retroflexus shoot length was inhibited by the R+L EO more than other EOs while most root growth inhibition caused by S. hortensis EO. For B. tectorum, and tomato, S. hortensis had the strongest inhibitory effect on root and shoot elongation.
Keywords: Weed control; Inhibitory effect; Essential oils; Allelopathy; Monoterpenes
... Natives usual pesticides and fumigants to keep stored legumes from creature insect invasion. Although plant based allelochemicals are widely used herbicide (Arora et al., 2015;Yazlik and Uremis, 2016). In a country like ours; significant work rarely done to recognize the insecticidal potency of plant materials against stored grain pests except neem {Azadirachta indica), which is very effective against several insect pests including pulse beetles (Jilani and Malik, 1973;Naqvi, 1987 andJilani et al. 1988;Elzaki and Ali, 2015). ...
Legumes (pulses) are ancient crops of the Sub-continent, Middle East and various parts of the Africa. These provide high quality protein and considered to be the best food for vegetarian population in India, South Asia, West Asia and Southern European countries. Chickpea is valued for its nutritive grains with high protein content of 25-29%. These grain legumes are, however, susceptible to different species of beetles of the family Bruchidae in storage commonly known as Dhora. At current, insect manage procedures frequently rely on synthetic insecticides and fumigants. Other than substance safety actions may be result as like numerous severe drawbacks. Insecticides have wide and unsystematic application causes natural imbalance confrontation to insect, insect recovery and epidemic of secondary insect creates phyto-toxicity. Insecticide residues in diet and nourish. Furthermore, non-stop use of insecticides leads to harmful result on insect pollination, biological agent like different Predators, parasitoids and too become cause of the ecological contamination. Owing to these drawbacks, internationally scientists are annoying to approve substitute methods of insect manage. The make use of close by obtainable native place resources in the management of harmful insects are a primeval technology. Now in modern world, in numerous parts of the earth a range of crop of vegetation have been tried lately by researchers with an elevated amount of achievement as granule. Protestants next to pulse beetle to decrease plague in storage space. Observance these views in brain, the in attendance learning was conducted to examine the pesticide efficiency of a number of native botanicals powders as granule protestant next to Callosobruchus. chinensis legumes grains. Reviewed shows that different plant material which are friendly with ecosystems have significant results against pulse beetle and serve as an alternative methods for the pest control.
... Intercropping has proven its ability to suppress weeds basically through two strategies. Intercrops may exert resource competition with weeds and may involve in allelopathic interactions, which are detrimental to the growth of weeds (Arora et al., 2015;Liebman and Dyck, 1993;Seran and Brintha, 2010). However, in some instances, the intercropping system by itself would not be able to provide a satisfactory level of weed control unless the best component crops are selected along with the best compatible environmental condition (Lithourgidis et al., 2011;Seran and Brintha, 2010). ...
Integrated weed management (IWM) strategies composed of non-chemical methods provide many beneficial effects to the agro-ecosystems, including growth and development of crops. The focus of this review is to explore the potential of intercropping as a non-chemical weed management technique in IWM in selected tropical root and tuber crops namely, sweet potato, yam, and cocoyam. Fast-growing and short-duration crops are suggested to be intercropped with root and tuber crops cautiously to achieve high intercrop productivity in such systems. Yam-pumpkin intercrop has reduced weed growth by 70% and increased the yield of component crops by 30–50% whereas sweet potato-maize-cocoyam intercrop has reported a 50–90% of yield depression in component crops in the absence of weed control measures. This signifies the importance of selecting a spatially and temporally compatible intercrop combination for weed control and higher yields of component crops in an intercrop. Sweet potato-maize-soybean system, sweet potato-peanut system, yam-fluted pumpkin/melon-okra/maize system and sun hemp-taro system have shown evidence to be compatible within each system and resulted in better weed control and higher crop yields. It is recommended to plant sweet potato at a density of 33,333 plants ha−1 with peanut at a density of 66,667 plants ha−1 for the lowest weed density and the highest yield advantage whereas ideal density levels of selected intercrops are yet to be researched in most of the intercropping systems with root and tuber crops. A limited number of researches have been successfully conducted to find out compatibility levels of intercrops focusing on the degree of weed management and yield advantage of sweet potato-, yam-, and cocoyam-based intercrops. Hence, further research is mandatory prior to endorsing intercropping as an effective weed management technique in root and tuber crops.
... Thus, the concentration of the EOs increases, so does the active component present in the oils and hence there is an increase in the activity of the oils in this case represented by larger inhibition zones. [39,40]. In this study, differences in the solubility, diffusion, and evaporation rates of the essential oils in agar and broth media could be some of the factors that contributed to the observed differences between the two methods. ...
The objective of this study was to determine the chemical composition and antibacterial activity of essential oils (EOs) of Tagetes minuta against three phytopathogenic bacteria: Pseudomonas savastanoi pv. phaseolicola, Xanthomonas axonopodis pv. phaseoli, and Xanthomonas axonopodis pv. manihotis.The essential oils were extracted using steam distillation method in a modified Clevenger type apparatus while antibacterial activity of the EOs was evaluated by disc diffusion method. Gas chromatography coupled to
mass spectrometry (GC/MS) was used for analysis of the chemical profile of the EOs. Twenty compounds corresponding to 96% of the total essential oils were identified with 70% and 30% of the identified components being monoterpenes and sesquiterpenes, respectively.The essential oils of T. minuta revealed promising antibacterial activities against the test pathogens with Pseudomonas savastanoi pv. phaseolicola being the most susceptible with mean inhibition zone diameters of 41.83 and 44.83mm after 24 and 48 hours, respectively. The minimum inhibitory concentrations and minimum bactericidal concentrations of the EOs on the test bacteria were in the ranges of 24–48mg/mL and 95–190mg/mL, respectively. These findings provide a scientific basis for the use of T. minuta essential oils as a botanical pesticide for management of phytopathogenic bacteria.
... Intercropping has proven its ability to suppress weeds basically through two strategies. Intercrops may exert resource competition with weeds and may involve in allelopathic interactions, which are detrimental to the growth of weeds (Arora et al., 2015;Liebman and Dyck, 1993;Seran and Brintha, 2010). However, in some instances, the intercropping system by itself would not be able to provide a satisfactory level of weed control unless the best component crops are selected along with the best compatible environmental condition (Lithourgidis et al., 2011;Seran and Brintha, 2010). ...
Cassava is an important root and tuber crop in the tropics which requires intensive weed management at
its early growth stages. This review emphasizes the potential of exploiting the option of intercropping as
a non-chemical tool of weed management in cassava. The appropriateness and the significance of
including intercropping solely and as a component of an integrated weed management system in cassava
are further discussed. Literature suggests that intercropping is a successful option in managing weeds
when the spatial and temporal compatibility of intercrop combinations is being achieved. In widespread
cassava-based intercropping systems, intercropping itself has proven its ability to alleviate weeds up to
30e60%, or even up to 100% with the selection of a better compatible crop mixture such as the cassavapumpkin
intercrop combination. A number of studies conducted to ascertain the appropriate spatial and
temporal compatibility levels of many intercrop combinations have provided evidence of their weed
suppressive ability in cassava-based intercropping systems. The focus of such studies towards the basic
agronomic, physiological and biochemical determinants of crop-weed interactions seems rather constricted.
In conclusion, intercropping is suggested to be exploited as an effective weed management tool
in cassava preferably through further research, prior to endorsing it as a proper alternative to chemical
weed control measures, especially for the resourceepoor farmers who probably can neither afford
herbicides nor labour-intensive cultural methods for weed management
Izdavanjem prvog udžbenika Biopesticidi namera nam je bila da prikažemo savremeni pristup i saznanja u oblasti zaštite bilja i da ukažemo na značaj primene biopesticida, kao alternativu hemijskim sredstvima za zaštitu bilja, kako u organskoj, tako i u integralnoj i konvencionalnoj poljoprivrednoj proizvodnji. Usled nedostatka odgovarajućeg udžbenika na gorepomenutom predmetu, a u nameri da se studentima omogući lako savladavanje gradiva, autori su pristupili izradi ovog udžbenika. Publikacija je napisana u skladu sa aktuelnim nastavnim planom i programom Poljoprivrednog fakulteta, Univerziteta u Novom Sadu.
Udžbenik sadrži uvodni deo koji se odnosi na osnovne definicije, značaj i podelu biopesticida, zatim oblike formulacija biopesticida, mehanizme delovanja biofungicida, bioinsekticida, bionematocida, bioherbicida, zaštita bilja u organskoj poljoprivrednoj proizvodnji, status biopesticida u zaštiti bilja, procena rizika primene biopesticida i zakonske regulative iz oblasti biopesticida. Pri pisanju ovog udžbenika korišćene su brojne starije i novije publikacije, rezultati stranih i domaćih autora, kao i sopstvena iskustva iz ove oblasti.
Osim studentima Organske poljoprivrede, udžbenik je namenjen i studentima drugih studijskih programa Poljoprivrednog fakulteta – Fitomedicina, Voćarstvo i vinogradarstvo, Ratarstvo i povrtarstvo i Pejzažna arhitektura, a svakako i onima koji rade u nastavi, nauci ili privredi. Prema našim saznanjima, udžbenik „Biopesticidi“ je prvi univerzitetski udžbenik na temu biopesticida u zaštiti bilja u zemlji i regionu, te može poslužiti studentima Poljoprivrednih fakulteta drugih univerziteta.
Essential oils have been used for centuries by communities all over the world in various areas and for various purposes. These include uses in medicine, flavoring, perfumery, cosmetics, insecticides, fungicides, and bactericides, among others. They are natural and biodegradable substances, generally nontoxic or with low toxicity to humans and other animals. Therefore, constant research in these areas represents an alternative for new and more efficient drugs with less side effects as well as obtaining new products and supplies. This book provides a comprehensive overview of the diverse applications of essential oils in a variety of human activities with a focus on the most important evidence-based developments in the various fields of knowledge.
Awareness about pollution worldwide through the excessive use of chemicals that affect every part of our environment makes the urgent need to use natural alternatives eco-friendly materials to reduce the losses come from synthetic chemicals. In recent decades, a great leap has been made to control weed by synthetic herbicides which are considered the most effective weed control method in comparison with the other methods. Although synthetic herbicides are considered less toxic between other pesticides such as insecticides and fungicides, the usual use, even if it is used at the recommended rates harmed the environment and human health. Previous works indicated that Essential oils have been demonstrated to have good phytotoxic activity on various plant species by suppressing germination and reducing growth parameters. Phytotoxic activity of essential oils can act directly as bioherbicide by effects on one or more than one of the biological processes inside plants which cause the death of plant completely or partially. This chapter highlights the desirable phytotoxic activity of essential oils and their possible uses as natural weed killers.KeywordsAllelopathyEssential oilsPhytotoxic activitySynthetic herbicidesNatural weed killer
Abdtract
Crop plants have defined roles in agricultural production and feeding the world. They are affected by several
environmental and biological stresses, which range from soil salinity, drought, and climate change to exposure
to diverse plant pathogens. These stresses pose risk to agricultural sustainability. To avoid the increasing biotic
and abiotic pressure on crop plants, agrochemicals are extensively used in agriculture for attaining desirable
yield and production of crops. However, the use of agrochemicals is also challenging the integrity of ecosystems.
Thus, to maintain the integrity of ecosystem, sustainable measures for elevated crop production are required.
Allelopathy, a process of chemical interactions between plants and other organisms, could be used in the
management of several biotic and abiotic stresses if the basic mechanisms of the phenomena and plants with
allelopathic potentials are known. Allelopathy has a promising future for its application in agriculture for natural
weed management, improving soil health and suppressing plant diseases. The aim of this review is to discuss
the importance of allelopathy in agriculture and its role in sustainability with a specific focus on weed manage-
ment and crop protection.
Weeds are constant companions of plant production. For their control chemical substances, ie herbicides are used. In addition to a number of properties, the use of herbicides has numerous consequences, for the living world and for the environment, as well. Considering their negative effects, there is a need to find alternative methods of weed control. In recent decades, numerous researches have been done within the framework of biologically and eco-friendlier acceptable ways of controlling various pests, including weeds. Bioherbicides are compounds that contain microorganisms (such as bacteria or fungi), products of their metabolism, or plant extracts that have an effect on certain weed species. In this paper, the application of plant extracts that show allelopathic effects, as potential bioherbicides, in modern agricultural production, will be discussed.
The multifaceted defense response of plants involves bioactive natural compounds that recognize, intervene, and neutralize the incoming pathogens. Plant secondary metabolites play roles at different stages of infection and disease progression. Studies have shown the synthesis of specific metabolites to confer resistance or tolerance depending on disease severity and other related factors. However, information on the presence, involvement, and regulation of several metabolites remains largely unavailable. The advent of next-gen omics approaches and the availability of high-throughput metabolomics platforms could expedite the studies in this direction. Given this, the present review details the role of secondary metabolites in plant defense, their modulation to achieve better immunity, and the tools and techniques available to study these metabolites. Further, the review also provides a roadmap for undertaking such studies in major crops to delineate the precise roles of novel metabolites and extrapolate the information for developing crops with better resistance against the broad-spectrum of pathogens.
Crop plants have defined roles in agricultural production and feeding the world. They are affected by several environmental and biological stresses, which range from soil salinity, drought, and climate change to exposure to diverse plant pathogens. These stresses pose risk to agricultural sustainability. To avoid the increasing biotic and abiotic pressure on crop plants, agrochemicals are extensively used in agriculture for attaining desirable yield and production of crops. However, the use of agrochemicals is also challenging the integrity of ecosystems. Thus, to maintain the integrity of ecosystem, sustainable measures for elevated crop production are required. Allelopathy, a process of chemical interactions between plants and other organisms, could be used in the management of several biotic and abiotic stresses if the basic mechanisms of the phenomena and plants with allelopathic potentials are known. Allelopathy has a promising future for its application in agriculture for natural weed management, improving soil health and suppressing plant diseases. The aim of this review is to discuss the importance of allelopathy in agriculture and its role in sustainability with a specific focus on weed management and crop protection.
Wild marigold (Tagetes minuta L.) is being commercially cultivated due to high demand of its essential oil in flavor and perfumery industry. Present study investigates pollination behavior, mechanism of pollination and floral developmental of wild marigold in to 11 stages each having distinct characteristic feature as observed by visual and light microscopy. Pollen production starts from stage-2, shape of pollen is spherical tricolpate and size varies from 0.025 - 0.031 mm. However, highest pollen availability and viability is observed at stage-6. Bilobed stigma protrude from the flowers at stage-7 indicating protandry. High bee activity is evident under open field conditions suggesting entomophilous mechanism of pollination. Based on viable seed formation and per cent germination, open field conditions are most suitable for good seed set as these conditions favor cross pollination. Despite poor seed set in self-pollinated condition germination percentage was not affected significantly. Floral biology of wild marigold suggests often cross pollinated breeding behaviour. Gas Chromatography - Mass spectrometry results showed significant variation in essential oil composition at foliage and inflorescence. The (Z)-β-ocimene (52.01 %) content was highest in inflorescence while dihydrotagetone (84.85 %) content was highest in foliage. Knowledge of pollination behavior of wild marigold is critical to decide the breeding strategies required for its improvement.
The essential oil of cultivated Tagetes minuta L. have been obtained by hydrodistillation and analyzed by GC–MS. A total of 27 compounds constituting 92% of essential oil of aerial part were identified. The main components were limonene (13.0%), piperitenone (12.2%), α-terpinolene (11.0%), piperitone (6%), (E)-tagetone (5.7%) and (Z)-ocimenone (5.1%).
The essential oil from the leaves of Tagetes minuta L., growing wild in Yemen, was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. A total of 28 compounds were identified representing 74.2% of total oil composition. Major components of the essential oil were (Z)-ocimenone (15.9%), (E)-ocimenone (34.8%), (Z)-beta-ocimene (8.3%), limonene (2.3%), (Z)-tagetone (1.8%), dihydrotagetone (1.4%) and an unidentified dimethylvinylketone derivative (20.6%). The oil showed moderate cytotoxic activity against MCF-7 breast tumor cells, with an IC50 of 54.7 +/- 6.2 microg/mL. In the DPPH radical scavenging assay, T. minuta oil showed potent antiradical activity with an IC50 value of 36 microg/mL. Antimicrobial activity was also investigated on several microorganisms, and the essential oil exhibited high activity against methicillin-resistant Staphylococcus aureus (MRSA) with an inhibition zone of 23 mm. It also exhibited remarkable antifungal activity against Candida albicans with an inhibition zone of 26 mm.
Chemical composition, antioxidant, antimicrobial and cytotoxic activities of Tagetes minuta (TM) essential oil (TMO) and Ocimum basilicum (OB) essential oil (OBO) were examined. The main components for TMO were dihydrotagetone (33.9%), E-ocimene (19.9%), tagetone (16.1%), cis-β-ocimene (7.9%), Z-ocimene (5.3%), limonene (3.1%) and epoxyocimene (2.03%). The main components for OBO were methylchavicol (46.9%), geranial (19.1%), neral (15.15%), geraniol (3.0%), nerol (3.0%), caryophyllene (2.4%). Inhibitory concentrations (IC50) for reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenging were 12-17 and 200-250 μg/mL of TMO and OBO, respectively. Minimal inhibitory concentration (MIC) against Salmonella typhi,Escherichia coli,Staphylococcus aureus,Bacillus subtilis,Aspergillus niger, and Candida albicans were 150 ± 8, 165 ± 9, 67 ± 8, 75 ± 7, 135 ± 15, and 115 ± 8 μg/mL of TMO, respectively. MIC for S. typhi,E. coli,S. aureus,B. subtilis,A. niger, and C. albicans were 145 ± 8, 160 ± 7, 45 ± 4, 40 ± 3, 80 ± 9, and 95 ± 7 μg/mL of OBO, respectively. IC50 for nasopharyngeal cancer cell line (KB) and liver hepatocellular carcinoma cell line (HepG2) were 75 ± 5 and 70 ± 4 μg/mL of TMO, respectively. IC50 for KB and HepG2 were 45 ± 4 and 40 ± 3 μg/mL of OBO, respectively. Thus, they could be used as an effective source of natural antioxidant and antibacterial additive to protect foods from oxidative damages and foodborne pathogens. Furthermore, they could be promising candidate for antitumor drug design.
Plants are widely used in the medicine industry of modern era, and are the sources of raw material and essential ingredients for medicines. These plant extracts and active constituents are used to make different formulations. Tagetes minuta, an annual ornamental plant, has been identified as potential medicinal plant
as it contains allelochemicals and essential oils that have multidimensional uses and applications such as weedicides, germicides, nematocides, insecticides, fungicides etc. Moreover, different medicines also have the fractions of these compounds. This plant is also used for beautification and landscaping i.e. as an
ornamental one. However, sometimes it appears to be a weed in lawns, parks and crop fields. In such case, it should be managed by mechanical, cultural and by chemical control methods. A comprehensive research is needed to explore more qualities and uses of this beneficial plant in future. Tagetes minuta L., a widely distributed plant in northern Pakistan, has immense and diverse utilities. The objective of the paper is to target this plant for exploitation and change its status from weed to underutilized minor crop.
The effect of volatile oil from leaves of Eucalyptus citriodora against some plant species viz. Triticum aestivum, Zea mays, Raphanus sativus, Cassia occidentalis, Amaranthus viridis and Echinochloa crus-galli was investigated. In a laboratory bioassay seed germination of test plants was significantly reduced in response to the different concentrations of the eucalypt oil. Maximum germination inhibition was observed with A. viridis, whereas least effect was seen on R. sativus. Based on the germination response, dose-response curve was generated and LC50 values were calculated. It was maximum for R. sativus whereas minimum for A. viridis. Further, seedling growth of the test plants and the chlorophyll content in the treated seedlings was significantly reduced at concentrations 0.12 and 0.3mg/l. Not only the initial growth, but also the spray treatment on the 4-week-old mature plants of two weedy species viz. C. occidentalis and E. crus-galli adversely affected the chlorophyll content and cellular respiration, thereby indicating the adverse effect of eucalypt oil on the photosynthetic machinery and the energy metabolism of the target plants. Based on the study, it is concluded that volatile oil from E. citriodora is phytotoxic and could be utilized as bioherbicide for future weed management programmes.
The potential use of natural phytotoxins (including allelochemicals) to develop novel tools for weed management is enhanced by the elucidation of their modes of action. This approach has not been emphasized by the agrochemical industry, although the possibility of discovering new target sites may be promising, since natural products tend to have modes of action different from synthetic herbicides. The approach of testing a compound on all known herbicide molecular target sites for commercial herbicides and other potent phytotoxins is feasible. However, this would preclude the discovery of new mechanisms of action. Discovering new target sites requires more challenging holistic approaches, initiated with physiological and biochemical studies that use whole plant assays. Studying basic plant responses to a compound may yield important clues to the specific physiological processes affected by the compounds and uncover novel mechanisms of action.
Fresh leaves and volatile oil of the important weed Ageratum conyzoides in south China were highly inhibitory to seedling growth of various cultivated crops, especially in an adverse habitat. The constituents of the volatile oil were analyzed by GC-MS. Eleven components were identified and six main components, precocene I, precocene II, 3,3-dimethyl-5-tert-butylindone, -caryophyllene, -bisabolene, and fenchyl acetate, were isolated by means of column chromatography. Precocene I, precocene II, -caryophyllene, and 3,3-dimethyl-5-tert-butylindone inhibited seedling growth of acceptor plants. Inhibitory activity of the volatile oil was more intense than that of the pure components. Fenchyl acetate and -bisabolene have no inhibitory activity, but when mixed with precocene II, they increased the inhibitory activity to growth of acceptor seedling plants. Experiments show that allelopathic synergism exists among allelochemicals of Ageratum conyzoides.
Several volatile allelochemicals were identified and characterized from fresh leaf tissue of three distinct populations of the invasive perennial weed, mugwort (Artemisia vulgaris). A unique bioassay was used to demonstrate the release of volatile allelochemicals from leaf tissues. Leaf volatiles were trapped and analyzed via gas chromatography coupled with mass spectrometry. Some of the components identified were terpenes, including camphor, eucalyptol, alpha-pinene, and beta-pinene. Those commercially available were tested individually to determine their phytotoxicity. Concentrations of detectable volatiles differed in both absolute and relative proportions among the mugwort populations. The three mugwort populations consisted of a taller, highly branched population (ITH-1); a shorter, lesser-branched population (ITH-2) (both grown from rhizome fragments from managed landscapes); and a population grown from seed with lobed leaves (VT). Considerable interspecific variation existed in leaf morphology and leaf surface chemistry. Bioassays revealed that none of the individual monoterpenes could account for the observed phytotoxicity imparted by total leaf volatiles, suggesting a synergistic effect or activity of a component not tested. Despite inability to detect a single dominant phytotoxic compound, decreases in total terpene concentration with increase in leaf age correlated with decreases in phytotoxicity. The presence of bioactive terpenoids in leaf surface chemistry of younger mugwort tissue suggests a potential role for terpenoids in mugwort establishment and proliferation in introduced habitats.
Determining the mode of action of allelochemicals is one of the challenging aspects in allelopathic studies. Recently, allelochemicals have been proposed to cause oxidative stress in target tissue and induce an antioxidant mechanism. alpha-Pinene, one of the common monoterpenoids emitted from several aromatic plants including forest trees, is known for its growth-inhibitory activity. However, its mechanism of action remains unexplored. The aim of the present study was to determine the inhibitory effect of alpha-pinene on root growth and generation of reactive oxygen species, as indicators of oxidative stress and changes in activities of antioxidant enzymes.
Effects of alpha-pinene on early root growth were studied in five test species, Cassia occidentalis, Amaranthus viridis, Triticum aestivum, Pisum sativum and Cicer arietinum. Electrolyte leakage, lipid peroxidation, hydrogen peroxide generation, proline accumulation, and activities of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT) and glutathione reductase (GR) were studied in roots of C. occidentalis.
alpha-Pinene inhibited the radicle growth of all the test species. Exposure of C. occidentalis roots to alpha-pinene enhanced solute leakage, and increased levels of malondialdehyde, proline and hydrogen peroxide, indicating lipid peroxidation and induction of oxidative stress. Activities of the antioxidant enzymes SOD, CAT, GPX, APX and GR were significantly elevated, thereby indicating the enhanced generation of reactive oxygen species (ROS) upon alpha-pinene exposure. Increased levels of scavenging enzymes indicates their induction as a secondary defence mechanism in response to alpha-pinene.
It is concluded that alpha-pinene inhibits early root growth and causes oxidative damage in root tissue through enhanced generation of ROS, as indicated by increased lipid peroxidation, disruption of membrane integrity and elevated antioxidant enzyme levels.
A simple, rapid method requiring few manipulations for the extraction of chlorophylls from fragmented leaf tissue of angiosperms and gymnosperms is compared with the widely used acetone method. Unlike the acetone method where grinding and subsequent centrifugation are essential, this method makes use of incubation at 65 °C of leaf tissue immersed in dimethyl sulphoxide. The new method was found to be as efficient as acetone for chlorophyll extraction and superior in terms of chlorophyll stability.
Volatile oils separated from the aromatic plants Coridothymus capitatus, Satureja thymbra and Rosmarinus officinalis markedly affected soil respiration, increasing manifold CO2 release, when added in the atmosphere over soil samples. Soil respiration can be retained in high levels for prolonged periods of time in presence of these natural products, since they are used as a carbon and energy source by soil microorganisms. -from Authors
Biorational alternatives are gaining increased attention for weed control because of concerns related to pesticide usage and dwindling numbers of labeled products, particularly for minor-use crops. Allelopathy offers potential for biorational weed control through the production and release of allelochemics from leaves, flowers, seeds, stems, and roots of living or decomposing plant materials. Under appropriate conditions, allelochemics may be released in quantities suppressive to developing weed seedlings. Allelochemics often exhibit selectivity, similar to synthetic herbicides. Two main approaches have been investigated for allelopathic weed suppression. One is use of living rotational crops or mulches that interfere with the growth of surrounding weeds [e.g., tall red rescue, Festuca arundinacea Schreb.; creeping red rescue, F. rubra L. subsp. commutata; asparagus. Asparagus officinalis L. var. altilis); sorghum, Sorghum bicolor (L.) Moench; alfalfa, Medicago sativa L.; black mustard, Brassica nigra (L.) Koch; and oat, Avena saliva L.]. Attempts to select germplasm with enhanced suppressive ability have been limited. The second is use of cover crop residues or living mulches to suppress weed growth for variable lengths of time (e.g., winter rye, Secale cereale L.; winter wheat, Triticum aestivum L.; and sorghum). Cover crop residues may selectively provide weed suppression through their physical presence on the soil surface and by release of allelochemics or microbially altered allelochemics. The ability to understand the physiological basis for allelopathy in a crop plant may allow the weed scientist or ecologist to work closely with molecular biologists or traditional plant breeders to selectively enhance the traits responsible for weed suppression.
Weeds are known to cause enormous losses due to their interference in agroecosystems. Because of environmental and human health concerns, worldwide efforts are being made to reduce the heavy reliance on synthetic herbicides that are used to control weeds. In this regard the phenomenon of allelopathy, which is expressed through the release of chemicals by a plant, has been suggested to be one of the possible alternatives for achieving sustainable weed management. The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particularly of crop plants, or by using allelochemicals as natural herbicides. In the former case, a number of crop plants with allelopathic potential can be used as cover, smother, and green manure crops for managing weeds by making desired manipulations in the cultural practices and cropping patterns. These can be suitably rotated or intercropped with main crops to manage the target weeds (including parasitic ones) selectively. Even the crop mulch/residues can also give desirable benefits. Not only the terrestrial weeds, even allelopathy can be suitably manipulated for the management of aquatic weeds. The allelochemicals present in the higher plants as well as in the microbes can be directly used for weed management on the pattern of herbicides. Their bioefficacy can be enhanced by structural changes or the synthesis of chemical analogues based on them. Further, in order to enhance the potential of allelopathic crops, several improvements can be made with the use of biotechnology or genomics and proteomics. In this context either the production of allelochemicals can be enhanced or the transgenics with foreign genes encoding for a particular weed-suppressing allelochemical could be produced. In the former, both conventional breeding and molecular genetical techniques are useful. However, with conventional breeding being slow and difficult, more emphasis is laid on the use of modern techniques such as molecular markers and the selection aided by them. Although the progress in this regard is slow, nevertheless some promising results are coming and more are expected in future. This review attempts to discuss all these aspects of allelopathy for the sustainable management of weeds. Referee: Dr. Amrjits S. Basra, Central Plains Crop Technology, 5912 North Meridian Avenue, Wichita, KS 67204
A simple, rapid method requiring few manipulations for the extraction of chlorophylls from fragmented leaf tissue of angiosperms and gymnosperms is compared with the widely used acetone method. Unlike the acetone method where grinding and subsequent centrifugation are essential, this method makes use of incubation at 65 °C of leaf tissue immersed in dimethyl sulphoxide. The new method was found to be as efficient as acetone for chlorophyll extraction and superior in terms of chlorophyll stability.
The present study investigated the chemical composition and allelopathic potential of volatile oil from Eucalyptus tereticornis on growth and establishment of Amaranthus viridis, a wasteland weed. The volatile oil was rich in monoterpenoids and a total of 34 components were identified by gas chromatography/gas chromatography–mass spectroscopy analyses, constituting 98.52%. α-Pinene (32.5%) and 1,8-cineole (22.4%) were the two major constituents. The volatile oil and two major components were evaluated for their allelopathic potential against A. viridis. A significant reduction in early seedling growth and seedling vigor of A. viridis was observed in response to volatile oil or its major monoterpenes. Further, the contents of photosynthetic pigments, i.e. chlorophylls a and b, and carotenoids, and cellular respiration in oil-/monoterpene-treated seedlings were significantly reduced thereby indicating adverse effects of the oil on photosynthetic machinery and energy metabolism. Based on the study, it can be concluded volatile oil of E. tereticornis possess allelopathic potential and could be explored as bioherbicide for future weed management programs.
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.
In the field, the growth of the aquatic weed Eichhornia crassipes and the alga Microcystis aeruginosa may be inhibited by fallen leaves of Lantana camara. This study showed that extracts of L. camara leaves and their fractions reduced the biomass of E. crassipes and M. aeruginosa within 7 days under laboratory conditions. Two fractions with highly inhibitory activity from the extract were isolated and subsequently identified as the pentacyclic triterpenoids, lantadene A and lantadene B. Both compounds significantly inhibited E. crassipes and M. aeruginosa growth, even at a low concentration. At all concentrations tested, their inhibitory activities were much higher than that of salicylic acid, a putative allelochemical from L. camara. The results indicated that the predominant allelochemicals involved in L. camara against either E. crassipes or M. aeruginosa are not phenolic acids, but lantadene A and lantadene B. Field trials showed that released levels of lantadene A and lantadene B were significantly correlated with amounts and decomposition periods of L. camara leaves floated in water. The amount released from 5 kg L. camara leaves was over the inhibition threshold of both E. crassipes and M. aeruginosa and reached a maximum at days 15–20. This study suggested that allelochemicals of L. camara could potentially be used to improve the management of weeds and algae in aquatic systems.
The chemical composition of essential oils from the flowering plants of four Tagetes species was examined by GC-MS. Of the species examined only T. minuta L. was rich in β-ocimene. The other major constituents of this species and of T. tenuifolia Cav. were dihydrotagetone, tagetone, and (E)-ocimenone. These two species only contained small amounts of (Z)-ocimenone but, in contrast, the essential oil of T. patula L. contained equal amounts of (Z)-and (E)-ocimenone. The oil from T. patula also contained limonene and β-caryophyllene. The essential oil from T. erecta L. differed largely from the other three species containing mainly limonene, β-caryophyllene, and piperitone. In agar-diffusion experiments the essential oil of T. minuta inhibited the multiplication of fungi, Gram-positive and Gram-negative micro organisms.
Tagetes minuta is an aromatic essential plant with wide range of biological activity including medicinal properties. A study was undertaken to explore the potential herbicidal activity of Tagetes minuta leaf powder (at 1, 2, and 4 t ha−1) towards two invasive weeds—Echinochloa crus-galli and Cyperus rotundus—of rice fields. It was observed that T. minuta leaf powder applied to rice field soil significantly reduced emergence and growth of both the weed species in pots under greenhouse and in rice field plots. At 1 and 2 t ha−1 dose of application, emergence and growth of weeds was severally affected, whereas there was no effect on the growth and yield attributes of rice. Rather, at this dose of application yield of rice increased significantly and the effect was similar to that observed with the herbicidal application under field conditions. Based on the study, it could be concluded that T. minuta possesses weed-suppressing ability and could be used as a natural herbicide.
The essential oils from aerial parts of Tagetes minuta L. grown in Egypt, South Africa and the UK were obtained by hydrodistillation. Although they had similar constituents, the oils had different percentage compositions. Dihydrotagetone was the most abundant component of the oils from the UK (34.3 and 54.1%), while the oils from South Africa and Egypt were characterized by a high content of cis-β-ocimene (50.9 and 32.0%, respectively). The oils exhibited antibacterial activity, especially against Gram-positive bacteria. Antimicrobial activity was greater in oils from the UK than in oils from Egypt or South Africa, irrespective of whether the UK plants had been grown in a greenhouse or in the field. The minimum inhibitory concentrations (MIC) for the oil from UK greenhouse-grown plants were 6.25–25 µg/mL for Gram-positive bacteria and 25–50 µg/mL for Gram-negative bacteria, with the lowest MIC of 6.25 µg/mL against Streptococcus faecalis. Oil from plants from South Africa had MICs of 50–100 µg/mL against Gram-positive and Gram-negative bacteria. The MICs of oil from plants from Egypt against all tested bacteria except Pseudomonas aeruginosa and Salmonella typhi were half of the MICs of oil from plants from South Africa. Copyright © 2004 John Wiley & Sons, Ltd.
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.
Volatile oils from Thymus capitatus, Satureja thymbra and, to a lesser extent, Rosmarinus officinalis stimulate soil respiration. The S. thymbra oil is fungistatic to the germination of Penicillium citrinum spores in soil, and to mycelial growth of Mucor hiemalis in liquid culture. Addition of the S. thymbra oil and, to a lesser extent, R. officinalis oil to soil result in increased bacterial numbers. Bacteria appear to use the oils as carbon and energy sources. Thus the oils appear to have an ecological effect by shifting the soil population balance from fungi to bacteria.
Wild marigold (Tagetes minuta L., syn. T. glandulifera, familia Asteraceae) is native to South America and naturalized in Europe, Africa, Asia and Australia. Its presence as an adventive plant on Balkan Peninsula was noted by Hayek (1931), Šilić (1973), Trinajstić (1974) and others. During the last 6-10 years wild marigold had appeared as weed in vineyards on the island of Hvar and become an agricultural and medical problem. However, it has also very interesting agrochemical and pharmacological properties. Disadvantages and advantages of wild marigold are considered. Weed control measures are discussed.
We investigated the chemical composition and phytotoxicity of the essential oil extracted from leaves of Artemisia scoparia Waldst. et Kit. (red stem wormwood, Asteraceae). GC/GC-MS analyses revealed 33 chemical constituents representing 99.83% of the oil. The oil, in general, was rich in monoterpenes that constitute 71.6%, with beta-myrcene (29.27%) as the major constituent followed by (+)-limonene (13.3%), (Z)-beta-ocimene (13.37%), and gamma-terpinene (9.51%). The oil and beta-myrcene were evaluated in a dose-response bioassay under laboratory conditions for phytotoxicity against three weeds-Avena fatua, Cyperus rotundus, and Phalaris minor. A significant reduction in germination, seedling growth, and dry matter accumulation was observed in the test weeds. At the lowest treatment of 0.07 mg/ml Artemisia oil, germination was reduced by 39%, 19%, and 10.6% in C. rotundus, P. minor, and A. fatua, respectively. However, the inhibitory effect of beta-myrcene was less. In general, a dose-dependent effect was observed and the growth declined with increasing concentration. Among the three weeds, the inhibitory effect was greatest on C. rotundus, so it was selected for further studies. We explored the explanation for observed growth inhibition in terms of reactive oxygen species (ROS: lipid peroxidation, membrane integrity, and amounts of conjugated dienes and hydrogen peroxide)-induced oxidative stress. Exposure of C. rotundus to Artemisia oil or beta-myrcene enhanced solute leakage, indicating membrane disintegration. There were increased levels of malondialdehyde and hydrogen peroxide, indicating lipid peroxidation and induction of oxidative stress. We conclude that Artemisia oil inhibits plant root growth through generation of ROS-induced oxidative damage.
The Allium test is suggested as a standard in environmental monitoring, e. g. as a part of a test battery. Background, the method including suggested parameters for standard use, results from various application areas and comparisons with a number of other test systems are presented. The Allium test is a short-term test with many advantages: low cost, ease to handle, good chromosome conditions for the study of chromosome damage or disturbance of cell division including the evaluation of risks of aneuploidy. The ability of the root cells to activate promutagens (the MFO-system) further widens the application areas of the Allium test. The use of series of onions for each concentration of the test chemical allows statistical considerations, and from growth curves Effect-Concentration values are obtained. The Allium test is, lastly, a sensitive test showing good correlation to other test systems. Thus, positive results in the Allium test should be considered as a warning and also an indication that the tested chemical may be a risk to human health and to our environment.
Essential oil of T. minuta has juvenile hormone activity on D. koenigii F.; 0.08 μl produces 64% sixth instar nymph. Higher doses reduce the formation of sixth instar nymphs, but the percentage of mortality during moulting increases. Higher dose of 0.2 μl gives 10% sixth instar whereas percentage of mortality during moulting goes up to 70%. It appears to be inactive on larvae and pupae of the mosquito, A. aegypti L., and pupae of the housefly, M. domestica L. The oil is fractionated, and the benzene fraction contains the active principle. The oil neither exhibits any chemosterilant properties on D. koenigii nor does it affect the pre- and postembryonic development of the eggs laid by treated females fertilized by untreated males, as well as by untreated females fertilized by treated males. Moulting of the first instar nymphs of D. koenigii treated with oil is usually checked. However, if a few nymphs moult they cannot survive beyond 24 hr after moulting.
The common onion (Allium cepa) is an excellent plant for the assay of chromosome aberrations after chemical treatment. Other species of allium (A. cepa var. proliferum, A. carinatum, A. fistulosum and A. sativum) have also been used but to a much lesser extent. Protocols have been given for using root tips from either bulbs or seeds of Allium cepa to study the cytological end-points, such as chromosome breaks and exchanges, which follow the testing of chemicals in somatic cells. It is considered that both mitotic and meiotic end-points should be used to a greater extent in assaying the cytogenetic effects of a chemical. From a literature survey, 148 chemicals are tabulated that have been assayed in 164 Allium tests for the clastogenic effect. Of the 164 assays which have been carried out, 75 are reported as giving a positive reaction (i.e., causing chromosome aberrations), 49 positive and with a dose response, 1 positive and temperature-related, 9 borderline positive, and 30 negative; 76% of the chemicals gave a definite positive response. It is proposed that the Allium test be included among those tests routinely used for assessing chromosomal damage induced by chemicals.
Batch experiments were conducted to assess the biotransformation potential of four hydrocarbon monoterpenes (d-limonene, alpha-pinene, gamma-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and alpha-terpineol) under aerobic conditions at 23 degrees C. Both forest-soil extract and enriched cultures were used as inocula for the biodegradation experiments conducted first without, then with prior microbial acclimation to the monoterpenes tested. All four hydrocarbons and two alcohols were readily degraded. The increase in biomass and headspace CO2 concentrations paralleled the depletion of monoterpenes, thus confirming that terpene disappearance was the result of biodegradation accompanied by microbial growth and mineralization. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. A significant fraction of d-limonene-derived carbon was accounted for as non-extractable, dissolved organic carbon, whereas terpineol exhibited a much higher degree of utilization. The rate and extent of monoterpene biodegradation were not significantly affected by the presence of dissolved natural organic matter.
Salvia leucophylla, a shrub observed in coastal south California, produces several volatile monoterpenoids (camphor, 1,8-cineole, beta-pinene, alpha-pinene, and camphene) that potentially act as allelochemicals. The effects of these were examined using Brassica campestris as the test plant. Camphor, 1,8-cineole, and beta-pinene inhibited germination of B. campestris seeds at high concentrations, whereas alpha-pinene and camphene did not. Root growth was inhibited by all five monoterpenoids in a dose-dependent manner, but hypocotyl growth was largely unaffected. The monoterpenoids did not alter the sizes of matured cells in either hypocotyls or roots, indicating that cell expansion is relatively insensitive to these compounds. They did not decrease the mitotic index in the shoot apical region, but specifically lowered mitotic index in the root apical meristem. Moreover, morphological and biochemical analyses on the incorporation of 5-bromo-2'-deoxyuridine into DNA demonstrated that the monoterpenoids inhibit both cell-nuclear and organelle DNA synthesis in the root apical meristem. These results suggest that the monoterpenoids produced by S. leucophylla could interfere with the growth of other plants in its vicinity through inhibition of cell proliferation in the root apical meristem.
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.
ISSN: 2313-8629) is an Open Access, Peer Reviewed online Journal, which publishes Research articles, Short Communications, Review articles, Methodology articles
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A catalogue of problem plants in South Africa. Memoirs of the botanical survey of South Africa No 53
- M J Wells
- A A Balsinhas
- H Joffe
- V M Engelbrecht
- G Harding
- C H Stirton
Wells, M.J., A.A. Balsinhas, H. Joffe, V.M. Engelbrecht, G.
Harding, C.H. Stirton. 1986. A catalogue of problem
plants in South Africa. Memoirs of the botanical survey of
South Africa No 53. Pretoria, South Africa: Botanical
Research Institute.
Chromosome aberration assays in Allium
- W F Grant
Grant, W.F. 1999. Chromosome aberration assays in Allium. A
report of the US Environmental Agency Gene–Tox.
Program. Mutat. Res. 99:273-291.
Essential oil and composition of Tagetes minuta from Uganda
- C M Kyarimpa
- S Bohmdorfer
- J Wasswa
- B T Kiremire
- I O Ndiege
Kyarimpa, C.M., S. Bohmdorfer, J. Wasswa, B.T. Kiremire
and I.O. Ndiege. 2014. Essential oil and composition of
Tagetes minuta from Uganda. Larvicidal activity on
Anopheles gambiae. Ind. Crops Pod. 62:400-404.
Chemical characterization of volatile components of Tagetes minuta L. cultivated in South West of Iran by nano scale injection
- M H Meshkataalsadat
- J Safai-Ghomi
- S Moharramipour
- M Nasseri
Meshkataalsadat, M.H., J. Safai-Ghomi, S. Moharramipour, M.
Nasseri. 2010. Chemical characterization of volatile
components of Tagetes minuta L. cultivated in South West
of Iran by nano scale injection. Dig. J. Nanomate. Bios.
5:101-106.