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Root‐mediated Allelopathic Interference of Nettle‐leaved Goosefoot (Chenopodium murale) on Wheat (Triticum aestivum)
Abstract
A study was conducted to determine the potential and nature of root-mediated allelopathic interference of Chenopodium murale on wheat. Early growth of wheat reduced significantly in agar medium where C. murale seedlings were previously growing as well as in rhizosphere soil of C. murale. The reduction in wheat growth was due to the presence of inhibitory metabolites released by roots of C. murale in the growth media. Even the soil incorporation of root residues also reduced the wheat growth in terms of seedling length and seedling dry weight. Only a partial amelioration in growth inhibition occurred upon charcoal supplementation or nitrogen fertilization in these amended soils. Root residues did not reduce the available nutrients in the soil, which was rather nutrient rich. These results indicated the definite role of allelopathy of C. murale roots in retarding wheat growth. Root amended soils contained significantly higher amount of phytotoxic phenolics as the putative allelochemicals, which were ferulic acid, vanillic acid, p-coumaric acid and benzoic acid. The study concluded that C. murale roots and their exudates exerted allelopathic effects on wheat by releasing water-soluble phenolic acids as putative allelochemicals in soil.
... Accordingly, to check the release of phytotoxic chemicals in the soil upon leaching/decomposition from Nicotiana plumbaginifolia roots, another experiment was planned in which the roots of Nicotiana were amended with soil. The methodology of Batish et al. (2007) with necessary modification was followed. Roots of Nicotiana collected from the earlier experiment were cut into small pieces (2-5 cm long) and the soil was collected locally from the upper (0-15 cm) profile of farmer's field around Aligarh. ...
... Later, Mahall and Callaway (1991) revealed that Larrea tridentata through its root exudates deleteriously disturbs the growth of neighbouring Ambrosia plants. Root exudation and decomposition of root residues have been attributed as one of the main pathways for the release of allelochemicals into soil medium (Batish et al. 2007;Bertin et al. 2003;Weston et al. 2012). Walker et al. (2003) suggested that root exudates contain a diversity of compounds, which includes amines, organic acids, carbohydrates, phenolics and several other secondary metabolites as well, which play a key role in root-mediated interactions. ...
... The limited amelioration in phytotoxic behaviour of root residues in the soil with the addition of activated charcoal (Table 2) specifies that the bioactive phytotoxins released by N. plumbaginifolia are organic biomolecules, as charcoal possesses a higher affinity for compounds that are organic than inorganic ones. Such a finding is parallel to the previous reports that observed a reduction in allelopathic effect in the soil upon addition of activated charcoal (Batish et al. 2007(Batish et al. , 2009Prati and Bossdorf 2004). Activated charcoal has been used since the 1900s to alleviate the inhibitory effect of phytotoxins in soil (Schreiner and Reed 1907). ...
Roots of weeds that are left behind in the soil after removal of their aerial parts can reduce the growth of crops. Here we conducted an assessment to evaluate the allelopathic interference of Nicotiana plumbaginifolia roots and its rhizosphere soil on the growth of Pisum sativum L., identification of chemicals involved, the role of charcoal, the role of N and other macronutrients. Growth responses of P. sativum were analysed for (a) rhizosphere soil with and without N supplementation and (b) soil amendment with Nicotiana roots. Scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) analysis of the rhizosphere soil was conducted to look for concentration of essential nutrients. Rhizosphere soil showed an inhibitory effect even with N supplementation. SEM-EDS showed a healthy concentration of essential nutrients. Root residues of Nicotiana integrated with soil do cause a reduction in seedling length (root length, shoot length) and dry biomass of recipient plant. However, a partial alleviation in growth inhibition occurred upon the addition of activated charcoal. Soils amended with root residues were rich in phenolics as compared to control. Overall, 34 compounds were reported upon GC-MS analysis which can be considered responsible for the allelopathic suppression of P. sativum. The chief component was guanosine (26.21%) followed by n-hexadecanoic acid (18.61%), oleic acid (18.29%), palmitoleic acid (4.80%),-(-)nico-tine (5.09%) and solasodine (2.54%). These results show a definite role of putative allelochemicals that exerted allelopathic effects on P. sativum.
... Allelochemicals exuded from roots of invasive plants and residue decomposition play an important role in inhibiting plant pathogens particularly those borne in soil [116]. However, amended soils with allelopathic residues tend to be rich in organic matter [117]. Electrical conductivity (EC) of the amended soils increased as compared to the control and all nutrients were significantly more [117]. ...
... However, amended soils with allelopathic residues tend to be rich in organic matter [117]. Electrical conductivity (EC) of the amended soils increased as compared to the control and all nutrients were significantly more [117]. Although, earlier reports show that inclusion of plant litter, in addition to releasing putative phytotoxins into the soil medium, alters the soil nutrient dynamics and, thus, affects the plant growth [106,112,116]. ...
... Allelochemicals exuded from roots of invasive plants and residue decomposition play an important role in inhibiting plant pathogens particularly those borne in soil [116]. However, amended soils with allelopathic residues tend to be rich in organic matter [117]. Electrical conductivity (EC) of the amended soils increased as compared to the control and all nutrients were significantly more [117]. ...
... However, amended soils with allelopathic residues tend to be rich in organic matter [117]. Electrical conductivity (EC) of the amended soils increased as compared to the control and all nutrients were significantly more [117]. Although, earlier reports show that inclusion of plant litter, in addition to releasing putative phytotoxins into the soil medium, alters the soil nutrient dynamics and, thus, affects the plant growth [106,112,116]. ...
... Weeds are non-economic plants that reduce crop yield (Mukhtar et al., 2012). Weeds along resource competition with crops exhibit allelopathy (Batish et al., 2007). Allelopathy is natural tool to increase crop yield by weed control reducing utilization of synthetic herbicides (Alagesaboopathi, 2010). ...
... Allelochemicals are released by different parts of the plant and leaves are most active in this respect (Rehman et al., 2014). The plant is reported to possess organic acids, alkaloids, tannins and flavonoids which hamper growth of adjacent plants (Canini et al., 2007). C. papaya is known to influence the growth of plants in its vicinity by the release of the allelochemicals during the decomposition of its litter (Christobel et al., 2017). ...
Due to increased number of herbicide resistant weeds, it is needed to explore the allelopathic potential of plants as an alternative. The research was conducted to investigate allelopathic effects of Carica papaya L. leaf powder and aqueous extract on seeds as well as pre-germinated seeds of Avena fatua L., Helianthus annuus L., Rumex dentatus L., Zea mays L. and Triticum aestivum L. on filter paper and soil in Weed Management Program Laboratory, Department of Plant and Environmental Protection at PARC Institute of Advanced Studies in Agriculture, National Agriculture Research Centre, Islamabad, Pakistan. Germination percentage (%), radicle length (cm) and plumule length (cm) were parameters observed for ‘Plant leaf powder bioassay’ and ‘Aqueous extract method’. Most significant growth inhibition was observed in A. fatua seedlings in filter paper method. A. fatua radicle length was reduced by C. papaya aqueous extract (80%) and leaf powder (89%) bioassays. Plumule length was reduced under the influence of aqueous extract (57-73%) and powdered material (59-77%). The inhibitory effects on other test species were in sequence of H. annuus followed by Z. mays and R. dentatus. The aqueous extract showed non-significant effect on wheat seed germination, radicle and plumule growth. It is suggested that C. papaya aqueous extract can be used as source of weed management in wheat crop.
... The seeds of C. murale have also been reported to possess certain allelochemicals (Qasem 1990). C. murale affected the wheat growth negatively by releasing the phenolic acids (benzoic, vanillic, p-coumaric and ferulic acids) in the rhizosphere (Batish et al. 2007b). It was also suggested that C. murale roots that remain in the soil even after eradication of the aerial plant parts may release some chemical compounds harmful to the growth of associated crops (Batish et al. 2007b). ...
... C. murale affected the wheat growth negatively by releasing the phenolic acids (benzoic, vanillic, p-coumaric and ferulic acids) in the rhizosphere (Batish et al. 2007b). It was also suggested that C. murale roots that remain in the soil even after eradication of the aerial plant parts may release some chemical compounds harmful to the growth of associated crops (Batish et al. 2007b). ...
Chenopodium album and C. murale are cosmopolitan, annual weed species of notable economic importance. Their unique
biological features, including high reproductive capacity, seed dormancy, high persistence in the soil seed bank, the ability to
germinate and grow under a wide range of environmental conditions and abiotic stress tolerance, help these species to infest
diverse cropping systems. C. album and C. murale grow tall and absorb nutrients very efficiently. Both these species are
allelopathic in nature and, thus, suppress the germination and growth of native vegetation and/or crop plants. These weed species
infest many agronomic and horticultural crops and may cause > 90% loss in crop yields. C. album is more problematic than
C. murale as the former is more widespread and infests more number of crops, and it also acts as an alternate host of several crop
pests. Different cultural and mechanical methods have been used to control these weed species with varying degrees of success
depending upon the cropping systems and weed infestation levels. Similarly, allelopathy and biological control have also shown
some potential, especially in controlling C. album. Several herbicides have been successfully used to control these species, but
the evolution of wide-scale herbicide resistance in C. album has limited the efficacy of chemical control. However, the use of
alternative herbicides in rotation and the integration of chemicals and biologically based control methods may provide a
sustainable control of C. album and C. murale
... Allelopathy is a universal mechanism between crops and between crop and weed, in which some chemicals are released from one plant species changing the growing environment in their vicinity and potentially affecting in positive or negative ways the associated crops (Colton & Einhellig, 1980;Tajuddin et al., 2002;Khan et al., 2011;Bagheri et al., 2014). Allelochemicals occur almost in all plant tissues like leaves, seeds and fruits, flowers, etc., and can be released together in the form of secondary metabolites (Singh et al., 2005;Batish et al., 2007) that may exert the effects in an additive or synergistic manner (Putnam & Tang, 1986). Allelochemicals are released into atmosphere through exudation as water soluble toxins, leaching of organic matter through decomposition and microbial by-products through non-living entities present in soil (Tukey, 1966;Fay & Duke, 1977;Chou, 1990;Mulatu et al., 2009). ...
... Allelochemicals are released into atmosphere through exudation as water soluble toxins, leaching of organic matter through decomposition and microbial by-products through non-living entities present in soil (Tukey, 1966;Fay & Duke, 1977;Chou, 1990;Mulatu et al., 2009). Allelopathic phenomena is not easy to understand because plant growth maybe influenced by immobilization of nutrients through microbes involved in decomposition or allelochemicals, or maybe through interaction effects of both phenomena (Batish et al., 2007). Several weed species are reported to have allelochemicals that affect the growth of crop plants (Mulatu et al., 2009;Fischer & Quijano, 1985). ...
Leaf aqueous extracts were used to examine the allelopathic effects of Melilotus indica, Medicago polymorpha, Elusine
indica and Fumaria indica at four concentrations (10, 20, 30 and 40% W/V) on germination percentage, radicle and
hypocotyl growth of six crops, namely Triticum aestivum, Hordeum vulgare, Medicago sativa, Trifolium spp., Raphanus
sativus and Trigonella foenum-graecum. All weed extracts showed pronounced inhibitory effect on germination and
seedling growth of tested crops, however inhibition was not consistent over studied parameters. Weeds exerted different
allelopathic effects on test crops. Fumaria indica exhibited a significant negative effect on germination of all tested species
at 20, 30 and 40% aqueous extracts, followed by Elusine indica and Medicago polymorpha, and Melilotus indica at 10%
concentration level. Melilotus indica halted the hypocotyl growth of tested crops at 10 and 20% aqueous extracts, followed
by F. indica at 30 and 40% dosage. Radicle growth of all recipient species was also stunted under the aqueous extract of M.
indica at 20, 30 and 40%, followed by Medicago polymorpha except 10% concentration. Elusine indica showed negative
effects on hypocotyl growth at higher concentrations as compared to Medicago polymorpha, whereas radicle growth was not
affected under different aqueous extracts of E. indica. Leaf debris method was used in greenhouse to further authenticate the
allelopathic effects of dominant allelopathic weed viz., Melilotus indica at four concentrations (0, 25, 50 and 75 g per 300 g
of soil) on germination percentage, shoot and root length of four crops, namely Medicago sativa, Trifolium spp., Hordeum
vulgare and Triticum aestivum. Powdered leaf debris of M. indica mixed with clay loam soil appeared to have strong
allelopathic inhibition under higher concentrations on germination and shoot growth of Medicago sativa and Trifolium spp.
as compared to Hordeum vulgare and Triticum aestivum, whereas inhibitory effects were more pronounced on Trifolium
spp. and Triticum aestivum, in terms of their root length. Hence, M. indica proved a strong allelopathic weed that should be
removed from field to avoid harmful effects during early growth stages of tested crops. Moreover, it is recommended that all
these species be phytochemically examined for their allelopathic potential and possible development of environmental safe
bio-herbicides to control weeds.
... Allelopathy is a universal mechanism between crops and between crop and weed, in which some chemicals are released from one plant species changing the growing environment in their vicinity and potentially affecting in positive or negative ways the associated crops (Colton & Einhellig, 1980;Tajuddin et al., 2002;Khan et al., 2011;Bagheri et al., 2014). Allelochemicals occur almost in all plant tissues like leaves, seeds and fruits, flowers, etc., and can be released together in the form of secondary metabolites (Singh et al., 2005;Batish et al., 2007) that may exert the effects in an additive or synergistic manner (Putnam & Tang, 1986). Allelochemicals are released into atmosphere through exudation as water soluble toxins, leaching of organic matter through decomposition and microbial by-products through non-living entities present in soil (Tukey, 1966;Fay & Duke, 1977;Chou, 1990;Mulatu et al., 2009). ...
... Allelochemicals are released into atmosphere through exudation as water soluble toxins, leaching of organic matter through decomposition and microbial by-products through non-living entities present in soil (Tukey, 1966;Fay & Duke, 1977;Chou, 1990;Mulatu et al., 2009). Allelopathic phenomena is not easy to understand because plant growth maybe influenced by immobilization of nutrients through microbes involved in decomposition or allelochemicals, or maybe through interaction effects of both phenomena (Batish et al., 2007). Several weed species are reported to have allelochemicals that affect the growth of crop plants (Mulatu et al., 2009;Fischer & Quijano, 1985). ...
Leaf aqueous extracts were used to examine the allelopathic effects of Melilotus indica, Medicago polymorpha, Elusine indica and Fumaria indica at four concentrations (10, 20, 30 and 40% W/V) on germination percentage, radicle and hypocotyl growth of six crops, namely Triticum aestivum, Hordeum vulgare, Medicago sativa, Trifolium spp., Raphanus sativus and Trigonella foenum-graecum. All weed extracts showed pronounced inhibitory effect on germination and seedling growth of tested crops, however inhibition was not consistent over studied parameters. Weeds exerted different allelopathic effects on test crops. Fumaria indica exhibited a significant negative effect on germination of all tested species at 20, 30 and 40% aqueous extracts, followed by Elusine indica and Medicago polymorpha, and Melilotus indica at 10% concentration level. Melilotus indica halted the hypocotyl growth of tested crops at 10 and 20% aqueous extracts, followed by F. indica at 30 and 40% dosage. Radicle growth of all recipient species was also stunted under the aqueous extract of M. indica at 20, 30 and 40%, followed by Medicago polymorpha except 10% concentration. Elusine indica showed negative effects on hypocotyl growth at higher concentrations as compared to Medicago polymorpha, whereas radicle growth was not affected under different aqueous extracts of E. indica. Leaf debris method was used in greenhouse to further authenticate the allelopathic effects of dominant allelopathic weed viz., Melilotus indica at four concentrations (0, 25, 50 and 75 g per 300 g of soil) on germination percentage, shoot and root length of four crops, namely Medicago sativa, Trifolium spp., Hordeum vulgare and Triticum aestivum. Powdered leaf debris of M. indica mixed with clay loam soil appeared to have strong allelopathic inhibition under higher concentrations on germination and shoot growth of Medicago sativa and Trifolium spp. as compared to Hordeum vulgare and Triticum aestivum, whereas inhibitory effects were more pronounced on Trifolium spp. and Triticum aestivum, in terms of their root length. Hence, M. indica proved a strong allelopathic weed that should be removed from field to avoid harmful effects during early growth stages of tested crops. Moreover, it is recommended that all these species be phytochemically examined for their allelopathic potential and possible development of environmental safe bio-herbicides to control weeds.
... It could exert its effects either as a stimulator [5], or an inhibitor for germination and growth for various crops viz. Triticum aestivum L. [6], Hordeum vulgare L. [4], and Melilotus indicus L. [7]. Eradication of weeds is a major concern for crop protection seekers. ...
Weeds are considered a great threat to crops. So weed eradication is an important task to increase crop yield. Chemical weed control in various crops decreases their nutritive potential. To overcome this problem to some degree, it is suggested to use these weeds instead of destroying them. Keeping this in view, such losses can be compensated by exploring their medicinal utility and identifying their future medicinal prospects. Chenopodium murale L. (Amaranthaceae) is an annual weed growing throughout the world. This review aims to summarize the reported pharmacology and phytochemistry of C. murale to explore its medicinal utility and identifying their future medicinal prospects. The review was done by literature collection from textbooks and online databases without a time limit. The weed name was confirmed by ‘The Plant List’. C. murale extracts, their isolated active constituents, and nanoparticles have been reported for various pharmacological actions like hepatoprotective, antihypertensive, antidiabetic, antidiarrheal, anticancer, antimicrobial, nematicidal, antioxidant, and cytotoxic. The pharmacological effects of C. murale may be due to the presence of secondary active metabolites such as phenolic acids, flavonols, terpenes and terpenoids, flavonoids and a steroidal glycoside. Reported phytochemistry and pharmacology suggest that C. murale could be an important medicinal agent for leishmaniasis, hypertension, infections and liver diseases. However, further studies are warranted.
... The phytochemical analysis of C. murale proved that the plant is rich in tannins, alkaloids, flavonoids, phenolic acids and saponins. These allelochemicals in C. murale were also in line with Zhou and Yu and Batish et al. [56,57]. ...
The present study was conducted to determine the allelopathic effect of the aqueous extracts of Cy-nanchum acutum, Anagallis arvensis, Chenopodium murale, Malva parviflora, Sonchus oleraceus and Por-tulaca oleracea on the germination and growth of Bidens pilosa plant. Also, the presence of total phenols, flavonoids, saponins, tannins and alkaloids, were screened in the studied plants. The results indicated that the aqueous extract of C. acutum, A. arvensis, C. murale, M. parviflora, S. oleraceus and P. oleracea showed a remarkable allelopathic effect on germination and growth of B. pilosa. The effectiveness of the extract was much higher on C. acutum, as it is the most effective in reducing the shoot and root growth of B. pilosa followed by S. oleraceus, M. parviflora, P. oleracea, C. murale and A. arvensis. The allelochemicals such as total phenols, flavonoids, saponins, tannins and alkaloids present in C. acutum, A. arvensis, C. murale, M. parviflora, S. oleraceus and P. oleracea. From the present study, it is concluded that the aqueous extract of the tested plants can be used as natural source in controlling B. pilosa.
... Phenolic compounds may stimulate protein synthesis and antioxidants even at very low concentrations (Hegab, 2005). Vanillic acid is one of the most important phenolics being used as natural antioxidants (Zhang et al., 2008), and VA has been identified in different plants such as Chenopodiastrum murale L. (Batish et al., 2007) and sweet clover (Macias et al., 1999). It was hypothesized that foliar application of vanillic acid on maize plants could improve their morphological, physiological, and biochemical responses to Cr toxicity. ...
... A. vogelii thrives well in arid and semi-arid regions. The residues left in the field exhibit allelopathic effects by releasing water soluble allelochemicals from its leaves, stems, roots, rhizomes, flowers, fruits and seeds (Agarwal et al., 2002;Batish et al., 2007;Naseem et al., 2009) However, despite the parasitic nature of A. vogelii to cowpea in Nigeria, there is paucity of information on its phytochemical composition and studies evaluating the effect of its extracts on growth performance of cowpea. Most of the studies were centered upon Striga species aqueous extracts (Olorunmaiye and Ogunfolaji, 2002;Jabeen and Ahmad, 2009;Romman et al., 2010;Kumbhar and Dabgar, 2011;Musniyi et al., 2012). ...
A study was conducted to evaluate the effect of Alectra vogelii (Benth) aqueous extracts on the growth parameters of cowpea (Vigna ungiucuata (L.) Walp). The experiment was carried out in the Orchard of the Department of Agronomy, Institute of Agricultural Research, Ahmadu Bello University, Samaru, Zaria, Nigeria in 2018. Qualitative and quantitative phytochemical screening of Alectra vogelii whole plant was carried out at National Research Institute and Chemical Technology (NARICT), Zaria. Alectra vogelii aqueous extract was applied on four varieties of cowpea: Sampea 7, Sampea 9, Sampea 10 and IAR-00-1074 at 0, 50, 100, 150 and 200 g/l, and the treatment were laid in complete randomized design with three replications. The growth parameters evaluated included plant height, number of leaves and root noodles at 5, 7 and 9 weeks after planting (WAP). Data obtained for growth parameters were analyzed using Analysis of Variance with Duncan’s New Multiple Range Test used to separate means that were significant. The result for phytochemical composition of A. vogelii whole plant showed the presence of five active phytochemical constituents: Saponins (46.50%), flavonoids (16.04%), tannins (0.247%), cyanogenic glycoside (0.212%) and alkaloids (0.08%). Significant difference (P≤0.05) was found in the effect of the extracts on growth parameters of cowpea. There is marked reduction in the growth parameters with increase in A. vogelii aqueous extract concentration. This implies that, A. vogelii extracts inhibits growth of cowpea with 200mg/l having the highest effect. Thus, the inhibitory action of A. vogelii can probably be attributed to the active phytochemicals present in the extracts Therefore, it is recommended that, A. vogelii residues should be well removed from farms as may inhibit the growth of cowpea due to their allelochemicals content.
... Allelochemicals produced by plant organs are released into the environment through (i) release of volatile organic compounds (Effah et al., 2019;Penuelas and Llusia, 1998;Santonja et al., 2019), (ii) decomposition of fallen leaves and needles (Fernandez et al., 2016;Hashoum et al., 2017;Nilsson, 1994), (iii) living root exudates (van Dam and Bouwmeester, 2016), and (iv) decomposition of dead roots (Bertin et al., 2003;Fernandez et al., 2016;Mallik et al., 2016;Tsunoda and van Dam, 2017). Phytotoxic substances in root exudates have been identified in various species such as Secale cereale (Pérez and Ormeno-Nuñez, 1991), Avena fatua (Pérez and Ormeño-Nuñez, 1991), Cucumis sativus (Yu et al., 2003;Yu and Matsui, 1994), Oryza sativa (Kato-Noguchi, 2004), Chenopodium murale (Batish et al., 2007) and Peperomia argyreia (Hao et al., 2010). Allelochemicals can alter neighbouring plant growth and functioning either directly (e.g. by interfering with root system growth and development, root nutrient uptake, or physiological processes) or indirectly through changes in belowground soil properties, such as physicochemical conditions (pH, ions availability…) (Huang et al., 2013;Xuan et al., 2005;Zeng, 2014) or soil community diversity, including N 2 -fixing bacteria and mycorrhizal associations). ...
Oak regeneration in temperate forests often fails in the presence of understorey grass. Competition by resource exploitation between plants has been extensively studied. By contrast, competition by interference, especially chemical interference (allelopathy), has been much less thoroughly examined and its relative importance remains unclear. We investigated the influence of allelopathic interaction on plant performance (biomass production) in a pot experiment with sessile oak (Quercus petraea) and purple moor grass (Molinia caerulea), either sole-or mixed-grown. Plants were watered with either Quercus root exudates or Molinia root exudates. After 6 months of growth, oak biomass increment was significantly lowered by Molinia root exudates. The oak's root system was more strongly affected than its aerial part. Quercus root exudates favoured oak growth but did not affect moor grass. Conversely, Molinia root exudates had a small depressive effect on its own growth, but its biomass was favoured by the presence of oak grown in the same pot. Resource exploitation had a more detrimental effect than allelopathy and both processes together decreasing oak biomass by 50%. Although untargeted metabolomic analysis by UHPLC failed to identify any potentially allelopathic substances involved, our study demonstrates a lower but critical contribution of chemical interference on oak seedling-moor grass competition compared to exploitation processes. To ensure oak regeneration, management of forest ecosystems should thus first focus on reducing moor grass close to oak seedlings to help decrease its allelopathic effect and ease resource competition.
... Vanillic acid is one of the most common phenolic compounds found in different plant parts. It was previously identified in extracts from different plants such as Alnus japonica, Gossypium mexicanum, Rosa canina, Panax ginseng [29], and Chenopodium murale [30]. Vanillic acid can act as an antimicrobial, antioxidant [31], anti-inflammatory, and antidiabetic agent [32]. ...
The allelopathic potential of plant species and their related compounds has been increasingly reported to be biological tools for weed control. The allelopathic potential of Garcinia xanthochymus was assessed against several test plant species: lettuce, rapeseed, Italian ryegrass, and timothy. The extracts of G. xanthochymus leaves significantly inhibited all the test plants in a concentration- and species-specific manner. Therefore, to identify the specific compounds involved in the allelopathic activity of the G. xanthochymus extracts, assay-guided purification was carried out and two allelopathic compounds were isolated and identified as methyl phloretate {3-(4-hydroxyphenyl) propionic acid methyl ester} and vanillic acid (4-hydroxy-3-methoxybenzoic acid). Both of the substances significantly arrested the cress and timothy seedlings growth. I50 values (concentrations required for 50% inhibition) for shoots and roots growth of the cress and timothy were 113.6–104.6 and 53.3–40.5 μM, respectively, for methyl phloretate, and 331.6–314.7 and 118.8–107.4 μM, respectively, for vanillic acid, which implied that methyl phloretate was close to 3- and 2-fold more effective than vanillic acid against cress and timothy, respectively. This report is the first on the presence of methyl phloretate in a plant and its phytotoxic property. These observations suggest that methyl phloretate and vanillic acid might participate in the phytotoxicity of G. xanthochymus extract.
... Weeds compete with crops for moisture, nutrients, sunlight, and space (Capinera, 2014). Chenopodium murale is recorded as nuisance weed that compete with various crops such as barley (Al-Johani et al., 2012), wheat (Majeed et al., 2012), and chickpea (Batish et al., 2007). In this context, the present results revealed that the ethanol extract from costal samples showed higher phytotoxic activity against tested weed C. murale. ...
The objective of this study was to analyze the phytochemicals and to determine the antioxidant, antibacterial and allelopathic potential of three wild Mesembryanthemum species (M. crystallinum L., M. forsskaolii Hochst. Ex Boiss and M. nodiflorum L.). The phytochemical composition of the methanolic extract of studied species revealed the considerable quantities that might be responsible for their powerful antioxidant activity. The IC50 values were 386.51, 592.97, and 752.23µg/ml for M. nodiflorum, M. crystallinum and M. forsskaolii extracts respectively. The antibacterial activity index was calculated for each extract in comparison with the standard antibiotics. M. nodiflorum showed higher potency than ampicillin and penicillin G against against Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis. The allelopathic potential showed that the studied Mesembryanthemum species expressed a significant phytotoxic activity against Chenopodium murale weed in a dose dependent manner. M. nodiflorum sample showed the most phytotoxic effect among the studied species.
... Field observations reveal that Ch. murale competes with crops and causes reduction in crop qualities and yields (Anonymous, 1992). Batish et al. (2007) showed that root exudates and residues of Ch. murale significantly affect the wheat growth by providing the soil rhizosphere with phenolic allelochemicals. Báthory et al. (1982) observed that the Chenopodium species were contain sterols and steroidal oestrogens like substances. ...
... Vanillic acid is present in various fruits, cereal grains, olives, and different plants, along with beer, cider, wine [38,39], Gardeniae fructus [40], potato [41], red propolis [42], palm plant [43], Juglans regia [44], Angelica sinensis [45,46], Chenopodium murale [47], pumpkin seeds [48], Melilotus messanensis [49], orchard grass [50], and Poliomintha longiflora [51]. Vanillic acid is commonly used in different food preservatives, additives and flavoring agents and in the perfume industry [52]. ...
Wedelia chinensis (Asteraceae) is a wetland herb native to India, China, and Japan. It is a valuable medicinal plant recorded to have pharmaceutical properties. However, the phytotoxic potential of Wedelia chinensis has not yet been examined. Thus, we carried out this study to establish the allelopathic effects of Wedelia chinensis and to identify its phytotoxic substances. Extracts of Wedelia chinensis exhibited high inhibitory activity against the root and shoot growth of cress, alfalfa, rapeseed, lettuce, foxtail fescue, Italian ryegrass, timothy, and barnyard grass. The inhibition was varied with species and was dependent on concentrations. The extracts were separated through several purification steps, and the two effective substances were isolated and characterized as vanillic acid and gallic acid using spectral analysis. Vanillic acid and gallic acid significantly arrested the growth of cress and Italian ryegrass seedlings. The concentrations of vanillic acid and gallic acid needed for 50% inhibition (I 50 values) of the seedling growth of the cress and Italian ryegrass were 0.04-15.4 and 0.45-6.6 mM, respectively. The findings suggest that vanillic acid and gallic acid may be required for the growth inhibitory activities of Wedelia chinensis.
... Allelopathic potential of many crop plant and weeds have been investigated against different crops (Kato-Noguchi and Tanaka, 2006;Farooq et al., 2008;Jabran et al., 2010;Gulzar and Siddiqui, 2014). These plants release different types of water soluble phytotoxins in their surrounding environment and in soil thereby inhibiting the germination and growth of different crops (Kadioglue et al., 2005;Singh et al., 2005;Batish et al., 2007). These allelochemicals can be used as potential source for natural herbicides, pharmaceuticals and biological control agents (Hirai, 2003;Cheema et al., 2004;Norton et al., 2008;Jabran et al., 2008;Razzaq et al., 2012;Macias et al., 2007). ...
The present study intended to investigate the effect of aqueous extract from Calotropis procera on the growth of Brassica oleracea var botrytis. Seeds of brassica were soaked in solutions containing 20%, 40%, 60% and 80% concentrations of leaf, fruit and flower extract of C. procera. For control, distilled water was used. The effects of extracts on germination percentage, seedling growth, dry biomass, and relative water content were investigated. Higher concentrations of extract (60% and 80%) significantly reduced germination percentage, radicle length, plumule length, dry matter accumulation, and relative water content of the brassica seedlings as compared to control. The retardatory effect increases with the increase in the concentration of three types of extract used, with more pronounced effect noticed by leaf extract followed by fruit and flower extract. There were significant interactions among the different concentrations of extracts used, etype of extract with respect to gemination percentage, seedling length, dry biomass, and relative water content. The effect of pot based assay in relation to chlorophyll content was significantly reduced and antioxidant enzymes [superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities] show both significant and non-significant effect on antioxidant enzymes based on concentrations of extract and extract type used. The antioxidant enzymes show the significant decrease in its activity at low concentrations (20% and 40%) and non-significant increase at higher concentration (60% and 80%) of extracts in contrast to control. Based on the investigation, it could be speculated that the delayed germination and low germination rate of the test species after treatment by extracts could be due to the fact that extracts damaged the membrane system of the seeds and C. procera might release phe-nolics into the soil and these are probably involved in the growth inhibitory effect of test species.
... Allelochemical can be present any part of plants. These allelochemicals release from plants part by leaching, residue decomposition, root exudation, volatilization and other processes in both natural and agriculture system (Willis, 1999 andBatish et al., 2007). ...
Sandal (Santalum album L.) popularly known for its wide medicinal and economic importance belonging to the family Santalaceae. Present research work was divided into two parts. A: Rhizosphere fungi: Serial dilution plate technique was used for isolation of rhizosperic fungi of S. album. In the present investigation total 71 isolates of 11 species of rhizosperic fungi were recorded. Out of 11 species 10 species belongs to Class Hyphomycetes viz. Aspergillus niger Van Tieghem, Aspergillus terricola Marchal, Penicillium spp., Aspergillus terreus Thom, Aspergillus flavipes Thom & Church Aspergillus funiculosus Smith, Aspergillus fumigatus Fresenius, Aspergillus flavus Link, Aspergillus restrictus Smith, Fusarium oxyporum Schlechtendahl ex Fries and one species i.e. Mycelia sterilia belongs to Basidomycetes. During the investigation Aspergillus niger, Aspergillus terricola and Penicillium spp. were frequently observed and recorded during study. B: Allelopathic potential: Laboratory experiment on the effect of leaf leachates of S. album on the germination of Trigonella foenum L. revealed that stronger the concentration of leachates greater the allelopathic effect on germination. No germination was recorded in the leachates from 25 gm (except 25 gm DLP for 4 hrs) and 50 gm of dry leaf powder (DLP). All the treatments showed significant effect of delayed in germination. The leachates of 5gm DLP for 4hrs to 24hrs reduced the growth of plumule from 4.59 cm to 3.95 cm respectively. Length of radical reduced from 0.45 to 0.20cm in the treatment 3 days after sowing (DAS) while in control, highest plumule and radicle growth was recorded i.e. 4.88 cm and 0.65 cm respectively.
... On the other hand, C. murale has been reported to have various allelochemicals such as benzoic acid, p-coumaric acid, ferulic acid, and vanillic acid. (Batish et al., 2007b) C. murale is a noxious weed as it interferes negatively with wheat, (Batish et al., 2007a;Majeed et al., 2012) barley, (Al-Johani et al., 2012) rice, (Alam and Shaikh, 2007) pea, and chickpea (Batish et al., 2007b) through its allelopathic activity. ...
The essential oil (EO) of Bassia muricata shoots was extracted via hydro-distillation and then investigated by gas chromatography-mass spectrometry. Thirty-four compounds were recognized for the first time from this plant, representing 100% of the total mass. Terpenoids represented the major components with 69.17% of the total mass, containing oxygenated sesquiterpenes (53.18%), oxygenated monoterpenes (9.77%), sesquiterpene hydrocarbons (5.03%), and diterpenes (1.19%). Additionaly, 6-methoxy-1-acetonaphthone was the only aromatic compound represented in a high percentage of the total identified compounds with 22.35%. Additionally, a percent of 8.48% of the total mass was hydrocarbons. Only one oxygenated sesquiterpene namely hexahydrofarnesyl acetone representing 47.35% of the total mass was identified. It was followed by methoxy-1-acetonaphthone (19.92%), n-dotriacontane (3.58%), endo-borneol (3.24%), 6-methy-α-ionone (3.04%), and α-gurjunene (2.65%). The EO exhibited moderate antioxidant activity comparable with ascorbic acid as a standard, where it attained IC50 value of 20.70 µL L⁻¹ and 16.32 µL L⁻¹, for DPPH and ABTS. The EO of B. muricata significantly reduces the germination and seedling development of the weed Chenopodium murale. The EO showed an IC50 value of 175.60 µL L⁻¹, 246.65 µL L⁻¹, and 308.33 µL L⁻¹ for root growth, shoot growth, and germination, respectively. Therefore, this EO could be a good green resource for the control of weeds.
... Nineteen species showed a low prevalence from 12.5-25% which are; Conyza bonariensis, Echium humile, Heliotropium europaeum, Lolium rigidum, Malva parviflora, Malva sylvestris , Papaver hybridum, Polygonum aviculare, Polygonum equisetiforme, Sonchus oleraceus, and Urtica pilullifera The previous recorded weeds which recorded as a ruderal may be in the future will become the aggressive weeds in the cultivated crops due to their high reproductive potential, fast growth rate, allelopathic nature causing inhibiting of the root length, shoot length, and weight of cultivated crops (Dagar et al., 1976;Hussain et al., 1992;Navie et al., 1996;Batish et al., 2007). InIndia and Pakistan, Rumex dentatus L. is also of major concern in various crops of economic importance including wheat, since it is a highly competitive weed and can cause drastic yield reduction (Chhokar et al. 2007;Anjum and Bajwa 2007;Mehmood et al., 2007). ...
The present study aims to record weeds plants within growing fields of Cucumber, Pepper, Tomato, Lettuce and Onion in Al- Oylia region ,Al-Marj ,Libya. A total number of 41 weed species 16 angiospermic families were found as a rudreal weeds. Maximum number of species (11) belongs to the family Poaceae (Graminaceae) followed by Cruciferea (Brasicaceae)(6) and Asteraceae (Composit) (4) .Aegilopos ventricosa, Centaurea Cyrenaica , were found to be the most frequently occurring weed with relative frequency (RF) 3.75 and 6.42% respectively , absolute frequency,(AF) of 29.2 and 50% respectively,(AD)1.54and 1.75 respectively, and they recorded in most Eight studied fields showing 75% prevalence. Nine species namely Allium roseum, Amaranthus retroflexus,Asphodelus tenuifolius, Avena sativa, Bromus rigidus,Phalaris minor,Phalaris canariensis, Rapistrum rugosum, and Urtica dioica showed 50% prevalence with absolute frequency (AF) ranging from 16.7–33.3% ,and relative frequency (RF) from 2.14–4.27%, and(AD) ranging from0.08-0.83 . The lest frequently occurring specieswith (AF) 8.33% and(AD) from 0.16-50 include six species. According to the frequency, three dominant weed species were found to be Aegilopos ventricosa, Allium roseum and Sinapis alba . Generally,the results in the present study showdominance of the ruderal over the agrestal weeds which may be due to ploughing and cleaning of agricultural soil.
... Chenopodium murale is reported as a nuisance weed that competes with various crops such as rice [57], barley [58], wheat [59], and chickpea [60]. It is worth mentioning here that the synthetic herbicides, 2,4-dichlorophenoxyacetic acid (2, 4-D), 2,4,5-trichlorophenoxyacetic acid (2, 4, 5-T), and 2-methyl-4-chlorophenoxyacetic acid (MCPA) were reported to inhibit the seed germination of C. murale by 97.06%, 61.76%, and 50.59%, respectively, at a concentration of 1000 ppm [61]. ...
The variation in habitat has a direct effect on the plants and as a consequence, changes their content of the bioactive constituents and biological activities. The present study aimed to explore the variation in the essential oils (EOs) and phenolics of Heliotropium curassavicum collected from the coastal and inland habitats. Additionally, we determined their antioxidant and allelopathic activity against the weed, Chenopodium murale. Fifty-six compounds were identified as overall from EOs, from which 25 components were identified from the coastal sample, and 52 from the inland one. Sesquiterpenes were the main class in both samples (81.67% and 79.28%), while mono (3.99% and 7.21%) and diterpenes (2.9% and 1.77%) represented minors, respectively. Hexahydrofarnesyl acetone, (-)-caryophyllene oxide, farnesyl acetone, humulene oxide, farnesyl acetone C, and nerolidol epoxy acetate were identified as major compounds. The HPLC analysis of MeOH extracts of the two samples showed that chlorogenic acid, rutin, and propyl gallate are major compounds in the coastal sample, while vanilin, quercetin, and 4′,7-dihydroxyisoflavone are majors in the inland one. The EOs showed considerable phytotoxicity against C. murale with IC50 value of 2.66, 0.59, and 0.70 mg mL−1 for germination, root, and shoot growth, respectively from the inland sample. While the coastal sample attained the IC50 values of 1.58, 0.45, and 0.66 mg mL−1. MeOH extracts revealed stronger antioxidant activity compared to the EOs. Based on IC50 values, the ascorbic acid revealed 3-fold of the antioxidant compared to the EO of the coastal sample and 4-fold regarding the inland sample. However, the ascorbic acid showed 3-fold of the antioxidant activity of the MeOH extracts of coastal and inland samples. Although H. curassavicum is considered as a noxious, invasive plant, the present study revealed that EO and MeOH extracts of the H. curassavicum could be considered as promising, eco-friendly, natural resources for antioxidants as well as weed control, particularly against the weed, C. murale.
... This could be due to accumulation of phytotoxin, which leads to phyto-toxicity and soil sickness (Gulzar and Siddiqui, 2016). Since, different plant species have different allelochemicals and can produce variable allelopathic effects (Kadioglue et al., 2005;Batish et al., 2007), it is imperative to assess the allelopathic effect of various tree species being used in agroforestry system on growth and yield of different understory crops. In present study, allelopathic effect of Acacia nilotica ( and Triticum aestivum L. (wheat) are being cultivated as intercrops during winter season in these agroforestry systems. ...
Different plant species produces different allelo-chemicals and variable allelopathic effects; hence, it is imperative to assess the allelopathic effect of various tree species, being used in agroforestry systems on growth of understory crops. In present study, allelopathic effect of aqueous leaf extracts of important gum-yielding plant species, namely Acacia nilotica, Acacia senegal, Anogeissus pendula and Butea monosperma on four winter season crops of Bundelkhand region were assessed in separate bio-assay trials. Study consisted of two factors viz., concentrations of leaf extracts [four levels: 15%, 10%, 5% and control (0%)] and test crops (Brassica campestris, Cicer arietinum, Lens culinaris and Triticum aestivum). Higher concentration of the extracts showed more inhibitory effects on seed germination and growth of test crops, in all the trials. Per cent (%) reduction in seed germination in different crops due to application of the extracts over control was found minimum in T. aestivum (in A. nilotica and B. monosperma) and C. arietinum (in A. senegal and A. pendula), and maximum in B. campestris , in all the trials. Similar results were also noticed in terms of total dry weight (mg) 5-1 plants in all test crops with selected gum-yielding plants. Thus, the results indicated that T. aestivum for A. nilotica and B. monosperma, and C. arietinum for A. senegal and A. pendula can be compatible intercrops; however, these are the results of bio-assay trials, hence field experiments need to be undertaken to evaluate the allelopathic effect of A. nilotica, A. senegal, A. pendula and B. monosperma.
... In cultivated crops, weeds are highly successful organisms in nature and established as an integral part of our agroecosystem [2]. Weeds always compete for the light, moisture, macro, and micronutrients with the neighboring crop plants for their growth and development and influence to the crop productivity by liberating a number of chemicals in the soil through roots [3]. The biologically active chemicals that released to the soil are so-called allelochemicals [4]. ...
... Allelopathy is defined as the direct or indirect inhibitory or stimulatory effects of one plant on another plant through the production of bioactive chemical compounds called allelochemicals or allelopathins, which escape or released into the environment (Saxena et al., 2016). This phenomenon includes interference between weed-weed, weed-crop or crop-crop (Batish et al., 2007, Chon et al., 2003, Lehoczky et al., 2011. Release of allelochemicals is held as a major factor in regulating the structure of plant communities in both natural and agroecosystem (Gawronska andGolisz, 2006, Smith andMartin, 1994). ...
The present study was carried out to evaluate the allelopathic potential of ten common weeds against three crop plants. All weeds extracts, even those more diluted, completely prevented seeds of Eruca sativa from germination. The high extract strength of Ammi majus and Desmostachya bipinnata prevented seeds of Triticum aestivum and Vicia faba from germination. The germination percentage, seed vigor index, coefficient of velocity and seedling length of T. aestivum and V. fabadifferentially inhibited by the extracts of weeds. The rate of elongation of hypocotyl and epicotyl of T. aestivum inhibited by all weeds, while the low extract strength of six weeds stimulated the rate of elongation in V. faba sprouts. All estimated germination and elongation parameters of receiving plants negatively correlated by total phenolics, flavonoids and alkaloids in donor weeds. Terpenoids were less influence and weakly correlated with germination parameters, so it suggested to be stimulatory. The magnitude of allelopathic effect, inhibitor or stimulator, was primarily depends on the donor plant and its content of secondary metabolites and secondarily on the target species as indicated by 2. The weeds exerting negative allelopathy can be categorized into competitive weeds which inhibit cell division and elongation or phytotoxic weeds that germination-preventing.
... Thus, it is not recommended in fields with this specie (Fig. 3). Besides the compounds mentioned in this study, saponins, phenols and benzoic acid can reduce germination and the seedling development of different species (Batish et al., 2007, Shahrokhi et al., 2011. ...
Allelopathy is an important mechanism by which plants release allelochemicals. This study aimed to evaluate and compare the allelopathic effect of extracts of fruit tree leaves (orange, mango, jabuticaba and guava trees) on the germination and seedling development of different weeds (morning glory and beggartick) and vegetable crops (lettuce and cabbage). The FGC and G were evaluated. After germination, SDM and SL were measured. In general, first germination counting (FGC) and G (germination) were decreased for all species conducted with the allelopathic extracts in relation to the control. Mango extract reduced the FGC of morning glory in 20 p.p.m. The G of beggartick reduced to 0%, while cabbage and lettuce germination was not affected. The highest reduction on FGC was observed in lettuce using jabuticaba extract, usinf 9 p.p.m, compared to the control. The extracts reduced the G of morning glory and beggartick, respectively, in between 5 and 11 p.p. Jabuticaba extract reduced significantly the G of morning glory and beggartick. The development of morning glory and beggartick was negatively affected by allelopathic extracts. The G of morning glory and beggartick is affected by the jabuticaba extract. The development of cabbage seedling was affected when all extracts were used and guava extract affected the length of cabbage seedlings. Mango extract has potential to control morning glory and beggartick in established lettuce and cabbage fields. Mango, orange, jabuticaba and guava extracts have the potential to control weeds on lettuce established fields. Guava extract is not indicated to control weeds on cabbage cultivated fields.
... Weed management is a current need because weeds are widely distributed in agricultural systems, and there is 9.7% yield loss as a result of 1,800 different types of weeds in agricultural crops per year (Li and Wang, 2010). Weeds not only compete with crops for water, nutrients and sunlight but also suppress crop plants by secreting some inhibitory chemicals known as allelochemicals into the rhizosphere which are responsible for the reduction in growth and yield of crops (Batish et al., 2007;Tanveer et al., 2010;Gatti et al., 2010). There are about 250 species 3 of weeds which are responsible for agricultural losses all over the world (Dangwal et al., 2010). ...
In the current study the herbicidal potential of different dryland plant species to suppress tuber sprouting and growth in the purple nutsedge (Cyperus rotundus) was investigated. The plant species evaluated were Fagonia indica, Aerva javanica, Calotropis procera, Rhazya stricta and Withania coagulans. In a greenhouse experiment, 5 sprouted and 5 non-sprouted tubers of nutsedge were planted in pots containing 250g field-collected soil. Pots were irrigated regularly with aqueous extracts of test plants at five concentrations (0, 25, 50, 75 and 100%; original extract was concentrated 20 times and was considered as 100% concentrated and further concentrations were made accordingly). Extracts of all test plants significantly inhibited nutsedge tuber sprouting and growth. A significant interaction was observed between sprouting index (SI) and final sprouting percentage. While a non-significant interaction was observed between the timing of sprouting initiation and mean sprouting time (MST). Maximum reductions in SI and final sprouting percentage were recorded with Rhazya stricta extracts. Extracts of Rhazya stricta showed maximum suppressive potential of nutsedge density, root and shoot length, root and shoot fresh and dry weight. Overall, the least effective suppression of purple nutsedge was observed for extracts of Fagonia indica. Calotropis procera extracts resulted in the lowest reductions in nutsedge root length of all test plants but all test plants showed similar effects on timing of sprouting initiation and mean sprouting time. The 100% and 75% concentrations provided complete suppression of nutsedge. For all test plants, the 25% extract concentration was least effective and in some cases results were similar to the water-only control treatment. Our findings suggest that several dryland plant species with strong allelochemical properties have the potential to substantially reduce the deleterious impacts of purple nutsedge in dryland cropping systems and warrant further study.
... Allelopathy is an interference process where plant releases one or more biochemicals (known as allelochemicals) which influence the growth and fitness of other plants. The allelochemicals have positive or negative effects on the target plants ( Rice, 1984;Batish et al., 2007;Farooq et al., 2011;Cheng and Cheng, 2015). The negative impacts on human and environment after the use of synthetic herbicides for weed control has been taken a consideration to a safer replacement of chemical herbicides (Beckie, 2006;Jabran et al., 2015). ...
Cyanotis axillaris, an annual succulent weed in the family Commelinaceae, was taken in this experiment to explore its allelopathic potential as plant allelopathy is considered as a biological option to control weeds. The aqueous methanol extracts of C. axillaris were applied on the growth of four dicotyledonous (cress, lettuce, alfalfa and rapeseed), and four monocotyledonous (barnyard grass, Italian ryegrass, timothy and foxtail fescue) test plant species at six different concentrations. The C. axillaris extracts inhibited the shoot and root growth of all test plant species, and such inhibition increased with increasing extract concentrations. Cress and lettuce showed complete growth inhibition at the concentration of 0.1 g dry weight equivalent extract/ml, whereas alfalfa, rapeseed, barnyard grass, Italian ryegrass, timothy and foxtail fescue showed growth inhibition greater than 50% of the control growth. At a concentration of 0.3 g dry weight equivalent extract/ml of C. axillaris extracts, cress, lettuce, alfalfa and rapeseed showed complete growth inhibition and that inhibition was greater than 30% of the control growth for barnyard grass, Italian ryegrass, timothy and foxtail fescue. Comparing the required concentration for 50% growth inhibition, lettuce was more susceptible and timothy was less susceptible with the extracts. Results indicate that C. axillaris may have allelopathic activity and may contain growth inhibitory substances. Therefore, C. axillaris could be a potential candidate to develop environment-friendly bio-herbicides for weed control.
... Roy et al. (2006) stated that the aqueous methanol extract of some common weeds such as Chenopodium album, Striga densiflora, Luecus aspera, Eleusine indica, and Digitaria ischaemum album cause a significant delay and reduction in the growth of wheat and jute seedlings. In another experiment, Batish et al. (2007) discovered that the weed residue of Chenopodium murale significantly decreased the root and shoot growth of wheat. Aqueous tuber extracts of another common weed, Cyperus rotundus, was also discovered to have an allelopathic effect on the seedling growth of barley, cucumber, tomato, and rice seedlings (Meissner et al. 1979;Quayyum et al. 2000). ...
Paspalum commersonii (Poaceae) is a herbaceous perennial weed distributed in the tropics and subtropics regions and grows mainly in the moist, or even flooded soil. It often appears in the rice field as a competitive weed and difficult to manage. Its strong competitive nature indicates possible allelopathic potential of P. commersonii. However, no studies have been found yet on the allelopathic activity of P. commersonii. Thus, we investigated the allelopathic potential of this weed and determined its allelopathic substances. Aqueous methanol extracts of P. commersonii showed concentration-dependent inhibitory activity on the seedling growth of cress, alfalfa, rapeseed, lettuce, barnyard grass, foxtail fescue, Italian ryegrass, and timothy. Two substances were isolated through bioassay-guided fractionation and their structures were determined through spectral data as dehydrovomifoliol and loliolide. Dehydrovomifoliol and loliolide started inhibiting the shoot and root growth of cress at concentrations greater than 3 and 0.03 mM, respectively. The concentrations required for 50% inhibition (I50) of cress shoot and root growth were 3.34 and >3.50 mM for dehydrovomifoliol and 0.04 and 0.05 mM for loliolide, respectively. These results indicate that both substances may affect the inhibitory activity of P. commersonii.
... Weeds are one of the major problems in crop production (Marwat et al., 2008) as they compete with crop plants for nutrients, moisture, light, space, growth requirements, and exert allelopathic effects on crop seed germination and growth by releasing water-soluble compounds into the soil (Batish et al., 2007b;Kumar et al., 2009). A wide range of injurious effects on crop growth has been reported as a result of phytotoxic decomposing products, released from leaves, stem, roots, fruit and seeds (Khan et al., 2009). ...
Alternanthera species are invasive aquatic/semi-aquatic weeds posing a serious threat to agro-biodiversity in several countries in the world. The present study was conducted to assess the phytotoxic effects of Alternanthera philoxeroides and A. sessilis residues on emergence and early seedling growth traits of rice (Oryza sativa). Soil was prepared with 4% (w/w) Alternanthera species residues separately and allowed to decay for 0, 15 and 30 days. Rice emergence was significantly decreased but increase in mean emergence time and time to 50% emergence was observed in soils modified with Alternanthera species residues compared with seed sown in unmodified soils. Rice emergence was reduced to 50-67% and 52-75% by A. sessilis and A. philoxeroides, respectively. A significant reduction in rice root, shoot length, and biomass was also noted with Alternanthera-infested soil. Total phenolics increased with increasing residue decay time in both species thereby showing their direct interaction with emergence and seedling traits of rice. The phenolic compounds identified were namely Quercitin, Chlorogenic acid, P-Coumeric acid, Trans-4-hydroxy3-methoxy, Cinamic acid, Caffeic acid, Syringic acid, Sinapic acid, Vanillic acid, 4-hydroxy-3-methoxy benzoic acid.
... Allelopathic plants have potential to modify the growth of neighbouring plants by releasing secondary metabolites. Allelochemicals are toxic substances which restrain the growth of other plants (Batish et al., 2007;Asgharipour, Armin, 2010), therefore release of toxic chemicals from different plant parts ultimately have influence on plants in its vicinity. Plant extracts obtained from different crop residues influence crop growth and yield (Farooq et al., 2008). ...
Brassica species have been reported as having allelopathic effect, reducing seed germination and emergence of subsequent cereal crops when grown in a rotation. Therefore, laboratory and greenhouse experiments were conducted to determine the allelopathic potential of rapeseed (Brassica napus L.) on germination and seedling growth of maize (Zea mays L.) under different salinity levels. Laboratory experiment consisted of two factors including different plant parts (root, shoot, leaf and whole plant) and their various concentrations (0, 5, 10, 15 and 20%). In a greenhouse experiment three factors were studied including different salinity levels (0, 4 and 8%), crop residue concentrations (0, 2 and 4%) and decomposition time (2 and 4 weeks). The experiment was laid out in a completely randomized design with factorial arrangement where treatments were repeated five times for germination experiment conducted in Petri plates and three times for soil bioassay experiment conducted in pots. The results showed that extracts of different plant parts could not affect the germination, while different concentrations showed significant effect on maize seed germination. The interaction of extracts of different plant parts with different concentrations significantly affected the growth. Root and leaf extracts at 5% concentration produced maximum root length, shoot length and plant dry weight as compared to other plant parts at other concentrations. For the second experiment or greenhouse experiment the results showed that neither plant parts nor decomposition period could influence germination significantly. However, salinity levels showed inhibitory effect on germination with increase in salt concentration. The rapeseed residue concentration of 2% with 4% salt concentration produced maximum plant fresh and dry weight. Rapeseed showed allelopathic potential on germination and seedling growth of maize, but this influence was decreased gradually with the increase of salinity.
... Also, Daizy et al. (2006) reported a reduction in the total chlorophyll content of chickpea and pea plants via the action of C. murale extracts. Batish et al. (2007) reported that C. murale extracts had a large number of phytotoxic phenols that affected the wheat overall plant growth and physiology by releasing water soluble phenolic acids in the soil through their roots. Different genotypes posses different allelopathic activity; i.e., the maximum allelopathic ability was achieved from Q-52 followed by KVL-SAR2 and then Regalona as compared to the effects from Q-37 and KVL-SAR3 in the tested plants. ...
ive quinoa (Chenopodium quinoa Willd.) genotypes; namely, KVL-SRA2, KVL-SRA3, Regalona, Q-37 and Q-52 were evaluated, under rainfed and irrigated conditions, for their allelopathic potential. Four concentrations of 1, 2, 4 and 8 g/100 ml of the aqueous extract of all plant parts were assessed for their effect on the germination and initial development of some weeds and crops. HPLC/DAD/MS analyses were conducted for genotypes with highly inhibitory effects to determine their contents of phenolic compounds and saponins. The estimated EC 50 revealed that the aqueous extracts from genotypes grown under rainfed conditions had higher allelopathic activity than those genotypes grown under irrigated conditions. The suppressive effect of the extracts increased when the concentration of quinoa extracts increased. The highest reduction effects were achieved from Q-52; followed by Regalona and KVL-SRA2. Nevertheless, Q-37 and KVL-SRA3 caused minor amounts of inhibition in the tested plant traits. The negative influence of quinoa extracts was higher on monocotyledon plant species than on dicotyledon plant species. The highly susceptible plants were Hordeum vulgare, Allium cepa and Phalaris minor as compared to other tested plants. However, Vicia faba and Chenopodium album were slightly more susceptible plants. Qualitative-quantitative analysis showed sixteen flavonoids and three hydroxicinnamic acids (p-coumaroil derivatives); in particular, F
... Auxin participation in cell elongation thus possibly implies its role in stem elongation of the intact plant but also participates in regulation of cell division and differentiation (Trewavas, 2000). Allelochemicals are known to alter the plant metabolic processes (Cruz-Ortega et al., 2002) thus leading to reduced plant growth (Batish et al., 2007). It appears that BA played direct role in regulation of plant growth. ...
The present study was undertaken to investigate the impact of UV-B radiation and benzoic acid (BA) on growth and metabolism of Solanum lycopersicum L. cv. Pusa ruby. Benzoic acid and UV-B radiation have impact on growth and development of Solanum. BA treatment in two concentrations 0.5 mM and 1.0 mM and UV-B alone and in combination (UV + BA) reduced root and shoot growth and biomass of the seedlings. BA with and without UV-B has negative impact on pigment, protein and sugar contents of the seedlings. Carotenoids showed varied responses to the stresses. BA decreased carotenoid content while UV-B increased the level of carotenoids. Lipid peroxidation and electrolyte leakage also increased under both stresses. Antioxidant enzyme activities significantly enhanced under BA treatment, but increase was further escalated when seedlings simultaneously exposed to UV-B radiation. It is evident that UV-B radiation enhanced the toxicity of BA in Solanum seedlings.
We conducted an experiment at the Agronomy Field Laboratory, BAU, Mymensingh to evaluate the allelopathic effect of Mangifera indica, Artocarpus heterophyllus, Albizia lebbeck and Shorea robusta on the weed growth and yield performance of boro rice. The experiment consisted of one cultivar i.e. BRRI dhan29 and five different extract’s treatments such as no leaf extracts (T1), Mangifera indica leaf extracts(T2), Artocarpus heterophyllus leaf extracts(T3), Albizia lebbeck leaf extracts (T4) and Shorea robusta leaves extract (T5) @20:200 (w/v) ratio concentration. The experiment was laid out in a Completely Randomized Design with four replications. Weed population, weed dry weight were significantly affected by different treatments. The highest weed population and dry weight for all weed species were found in no tree leaf extracts treatments (T1) and Shorea robusta leaf extracts (T2) respectively. The lowest weed population and weed dry weight were recorded in Artocarpus heterophyllus leaf extracts (T3). The highest grain yield as well as the yield contributing characters was recorded in Albizia lebbeck leaf extracts (T4). The highest reduction of grain yield was observed in T1 (no tree leaf extracts) treatment. The longest plant height, highest number of total tiller hill-1, highest number of effective tillers hill-1, number of grains panicle-1, 1000-grain weight, grain and straw yields were observed in Albizia lebbeck leaf extracts (T4) treatment and the lowest was observed in T1. Results of this study indicates that Artocarpus heterophyllus (T3) and Albizia lebbeck (T4) leaf extracts showed potentiality in yield contributing characters of Boro rice. Therefore, Artocarpus heterophyllus and Albizia lebbeck leaf extracts might be used as an alternative way for weed management and sustainable crop production.
The rhizosphere is a microhabitat around plant roots that is actively created and regulated by plants, while having a major impact on plant life itself. Plants constantly enrich the rhizosphere with organic matter from their rhizodepositions and root exudates, shaping the chemical and microbiological composition of the space surrounding their roots. In this chapter, we discuss the interactions between plants and other organisms through the processes in the rhizosphere. Plant-associated microorganisms, such as plant growth-promoting bacteria and mycorrhizal fungi, play important roles in enhancing the survival of plants, through increasing the availability of nutrients from the soil to plants, degrading and immobilizing toxic compounds, alleviating the effects of abiotic stress, acting as biocontrol agents, protecting the plants from pathogens, and bolstering the efficiency of plant responses to biotic and abiotic stress. Moreover, plants use the rhizosphere as a battlefield for mutual competition by releasing allelochemicals that are detrimental to other plant species, and to harmful soil nematodes and insects. Similarly to land plants, aquatic plants also create a rhizosphere around their roots, with important implications for rice cultivation, methane emissions from wetlands, denitrification of aquatic habitats, and wastewater treatment through constructed wetlands. We emphasize how the existing and potential rhizosphere engineering approaches take advantage of the plant-associated microorganisms and allelopathic interactions between plants to improve the health and yield of agricultural crops, and help preserve the natural environment.
The current agricultural system is seeking a biological solution to lesson hazardous impacts from the use of chemicals to control weeds in rice production. Plant allelopathy is one of the ways where allelopathic plant inhibits its surrounding plants by releasing allelopathic substances. The present experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from July to December 2019 to study the allelopathic effects of the and residues of Eleocharis atropurpurea and Fimbristylis dichotoma on weed management and the yield performance of aman rice. The field experiment consisted of three rice varieties i.e BRRI dhan34, Nizershail and Kalozira and five treatments such as 0, 1.0, 2.0, 3.0 t ha-1 and farmer’s practices. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The highest grain yield (4.44 t ha-1) as well as the yield contributing character was recorded in Kalozira and the lowest grain yield (3.94 t ha-1) was obtained in the BBRI dhan34. The highest number of effective tillers hill-1, number of grains panicle-1, 1000-grain weight, grain and straw yields were observed when the residue of E. atropurpurea and F. dichotoma was applied at 3 t ha-1. Rice cultivar kalozira with the incorporation of E. atropurpurea and F. dichotoma residue at 3 t ha-1 produced the highest grain yield (5.08 t ha-1) and straw yield (6.77 t ha-1). Results of this study indicate that E. atropurpurea and F. dichotoma residue showed potentiality to inhibit weed growth and it has a significant effect on yield of aman rice.
The influence of dry leachates of Acasia saligna was tested on the seedling growth, photosynthesis, biochemical attributes, and gene expression of the economically important crops, including wheat (Triticum aestivum L.), radish (Raphanus sativus L.), barley (Hordeum vulgare L.) and arugula (Eruca sativa L.). Different concentrations (5%, 10%, 15%, 20%, and 25%) of stem extract (SE) and leaf extract (LE) of A. saligna were prepared, and seedlings were allowed to grow in Petri plates for 8 days. The results showed that all plant species exhibited reduced germination rate, plant height, and fresh and dry weight due to leachates extracts of A. saligna. Moreover, the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), exhibited differential regulation due to the extract treatment. The SOD was increased with increasing the concentration of extracts, while CAT and APX activities were decreased with increasing the extract concentrations. In addition, leachate extract treatment decrease chlorophyll content, photosynthesis, PSII activity, and water use efficiency, with evident effects at their higher concentrations. Furthermore, the content of proline, Distributed under Creative Commons CC-BY 4.0 sugars, protein, total phenols, and flavonoids were reduced considerably due to leachates extract treatments. Furthermore, seedlings treated with high concentrations of LE increased the expression of genes. The present results lead to the conclusion that A. saligna contains significant allelochemicals that interfere with the growth and development of the tested crop species and reduced the crops biomass and negatively affected other related parameters. However, further studies are suggested to determine the isolation and purification of the active compounds present in A. saligna extracts.
Background
The objectives of this study are to (i) determine the variations in the soil composition among six different habitats of six Rhus tripartita populations, (ii) identify and compare the variation in the fruit and seeds parameters of these populations, and (iii) evaluate the differences in Rhus tripartita allelopathic activities among populations on the Chenopodium album weed on it as biological control method.
Results
The soils analysis of the six habitats of Rhus tripartita populations revealed a significant variation in the soil variables, while salinity, organic matter, and macro-elements (Cl⁻, HCO³⁻, Na⁺, K⁺, Ca⁺ and Mg²⁺) were the most controlling factor. Rhus tripartita fruits and seeds showed that there is an inter-site variability observed between populations. Morphological study indicating a large-scale diversity among the provenances. It is related to the phenotypic characteristics which may be due to the genetic effect. The Rhus tripartita extract concentration, especially population 4 (P4), showed potential allelopathic activity against Chenopodium album, where the germination was strongly inhibited at a concentration of 10 g l⁻¹. Under same concnetration, seedling root length and shoot lenght were seriously affected.
Conclusion
These extracts could be used as green source, eco-friendly bioherbicide and to be integrated into the weed control program of weeds. However, further study is needed for characterization of essential oil of Rhus tripartita and their potential allelopathic activities against the Chenopodium album weed or maybe other weeds, and evaluate its valuable economic use on a large scale.
Keywords:
Rhus tripartita; Edaphic factors; Population; Morphological traits; Allelopathic activity
The widely adapted Eurasian summer annuals Chenopodium album and Chenopodium murale are opportunistic colonizers of disturbed areas that have spread globally via human vectors and long-term association of humans with agriculture. Chenopodium album is predominantly a weed of temperate zones, whereas C. murale is more prevalent at subtropical latitudes. Both species reduce yields by interference across a wide range of crops, with C. album consistently ranked among the top five worst weeds in North America. Management in many countries has been based largely on herbicides, resulting in the evolution of resistance to multiple modes of action in C. album populations since the 1980s. Research has shown that nonchemical alternatives can be effective against these weeds, including tillage, cover cropping, exploiting allelopathic crop residues, seed predation and fertilization timing, and some biocontrol agents. Future control of C. album and C. murale will require integration of herbicides with more diverse management strategies tailored to the local needs and resources of growers in different countries.
Calyptocarpus vialis (syn. Synedrella vialis; Asteraceae), a native of the tropical Americas, has acquired an invasive status in the eastern Asia and Africa and, of late, in India. It is an annual herbaceous weed that forms a dominant ground cover due to its prostrate expansion and interferes with the growth of other plant species. However, the reasons for this interference are largely unknown. Therefore, we examined the allelopathic interference of C. vialis via leachation and residue degradation on the emergence, growth, and development of three crop species (Brassica nigra, Triticum aestivum, and Avena sativa). In a laboratory bioassay, the leachates (0.5–4%) of C. vialis exhibited a dose-dependent inhibitory effect on various growth parameters of the test plants. Similarly, under screenhouse, C. vialis-amended soil (1–4%) affected the growth of test species in a dose-dependent manner. Further, the phytotoxicity of the residues of C. vialis was examined using rhizospheric soil (RS) and residue-amended soil (RAS). It was observed that RAS exerted the maximum allelopathic effect on the test species accompanied by significant changes in pH, electrical conductivity, and total water-soluble phenolic content, as compared with the control soil (CS) and RS. Liquid chromatography and mass spectroscopy analyses confirmed the presence of eleven allelochemicals as the major phytotoxins. The study demonstrated that C. vialis exerts strong phytotoxic effects on other plants through the release of potent allelochemicals, both via leachation and residue degradation.
Allelopathic effects of aqueous extract of rope weed and cranberry expression on five crops including wheat (Triticum aestivum), barley (Hordeum vuIgare), corn (Zea mays), millet (Pennisetum americanum) and chickpea (Cicer arietinum) in Shahid Bahonar University of Kerman, Iran Experiments in the greenhouse were conducted as a randomized complete block design and in the laboratory as a completely randomized design with 3 replications in different concentrations of aqueous extract of weed including (0, 25, 50, 75 and 100% base solution 10% W / V) in the germination stage. Seedling growth of all five crops was measured and different traits were measured. The results showed that the interaction effect of weed × concentration × cultivar on the measured traits was significant in both greenhouse and laboratory conditions. The highest inhibitory potential was related to grass. Weed was desert ivy, but nevertheless expression crap also had significant inhibitory potential. In general, with increasing the concentration of aqueous extract, the inhibitory effect also increased. So that the concentration of 100% was the highest and the concentration of control had the least effect on all traits. All five crops studied showed. In general, the results show that the remnants of rope weed and Farm crayfish have allopathic potential on crops, so they should be removed from the field before planting.
Allelopathic effects of aqueous extract of pagoda tree and creeping jenny on five crop plants including wheat (Triticum aestivum), barley (Hordeum vuIgare), corn (Zea mays), millet (Pennisetum americanum) and chickpea (Cicer arietinum) were investigated in a series of experiments conducted at the faculty of Agriculture, SB University of Kerman, Iran. Experiments were based on RCBD with 3 replications in greenhouse condition and CRD in laboratory condition in which different concentrations of weed leaves extract including (0, 25, 50, 75 and 100% of a stock solution (10%W/V)) were applied on all crop plants at germination and seedling growth stages and different responses were measured. Results showed that the three way interaction effect of alkaloid × concentration × hybrid was significant on the traits in both greenhouse and laboratory. By increasing the concentration of alkaloid, inhibitory effect was also increased. The 100% concentration was most effect and control concentration was least effective. There was a significant difference between the two weeds in terms of allelopathic effects and creeping jenny reduced plants growth more compared to pagoda tree. However, all crops were significantly affected by allelopathic properties. It was concluded that pagoda tree and creeping jenny residues in the field had the potential of allelopathic effects on crop plants therefore should be removed from the field before planting.
The objective of this study was to understanding the allelopathic dynamic of invasive species Eupatorium adenophorum residues against traditional crops viz., Amaranthus caudatus and Vigna unguiculata in laboratory and green house. In laboratory, the effect of different concentrations of the aqueous extract and leaf leachate of decomposed residues (DR) and un‐decomposed residues (UDR) of the selected weed was examined on shoot and root length of the selected crops. In pot study, different concentrations of dose and leachate of DR and UDR of selected weed was evaluated against growth and yield performance of the studied crops. Shoot and root length of both crops was significantly reduced by the aqueous extract of both kinds of residues. Aqueous extract at 8% of UDR residues was noticed to be harmful to V. unguiculata and reduced 66.23% and 75.28% shoot and root length, respectively. Similarly, soil amended with DR and UDR of the weed had a significant effect on growth and yield attributes of the studied crops and reduced 64.90% growth and 86.30% branch/plant of V. unguiculata at 8% concentration compared to control soil. A significant amount of water‐soluble phytotoxins was found in the UDR and DR of E. adenophorum. Leaf leachate of the selected weed was more harmful as compared to aqueous extract and soil amended residues. The UDR was found to be more phytotoxic than DR. These results suggest that the phytotoxic potential of E. adenophorum to plant community could be minimized if the whole plant of invasive weed is decomposed. Allelopathic dynamics of the residues of invasive weed was assessed. The undecomposed residue was more inhibitory to test crops as compared to decomposed. The phytotoxic effect of residues of invasive weed could be reduced if decomposed.
In order to investigation the effects of different concentrations of leaf aqueous extracts of walnut on seed germination and seedling growth of barley, arugula and corn, a laboratory experiment were conducted in the Faculty of Agronomy, Islamic Azad University of Isfahan, in 2013. In this experiment, walnut leaf extract including control (distilled water), 25, 50, 75 and 100% were studied to determine juglone sensitivity in three species based on completely randomized design (CRD) with four replications. Chromatography analysis showed that a highest rate of juglone was observed on walnut leaves in August. Increasing concentration of leaf extract lead to continuously decrease in germination percentage and germination rate, root and shoot length and seedling dry weight. Germination percentage of corn and arugula seeds on primary growth stage showed resistant to walnut allelopathy. The lowest germination percentage was observed on barley in %100 leaf aqueous extracts of walnut. Corn and arugula were more sensitive to walnut extracts than barley seeds, however, root and shoot dry weight in barley had no significantly different between treatments. The aqueous extract of walnut did not have a significant effect on germination components of barley, corn and arugula, so that corn and arugula in the early stages of germination and barley in seedling growth showed strong resistance. The insensitivity of the studied species showed that the aqueous extract of Iranian walnut leaves is a strong substance in controlling weeds of these species towards sustainable agriculture.
The application of allelopathy in sustainable agriculture was suggested as an environmentally friendly tool to manage weed infestation. This study aims to determine the phenolic compounds in the sorghum shoot extracts by liquid:liquid extraction using various solvents (ethanol, ethanol–chloroform, ethanol–hexane, ethanol–ethyl acetate, and ethanol–methylene chloride) and to assess weed control efficacy of the sorghum
extracts. Analysis of the phenolic compounds indicated that ethanol–ethyl acetate fraction contained highest phenolic compounds. Bioassay using four weed species, Abutilon avicennae, Digitaria sanguinalis, Amaranthus retroflexu, and Echinochloa crus–galli indicated that the extracts significantly inhibited the germination and growth of four weed species. In addition, the sorghum extracts had post–emergence activity for the weed species. Based on field studies, the sorghum shoot extract at 1 g/mL concentration and three times of applications at 7, 14, and 21 days after tillage controlled weeds more than 90% of untreated control. Based on the high herbicidal efficacy of the sorghum shoot extract extracted with ethanol–ethyl acetate, the sorghum extract is a promising material and might be used as a natural herbicide in the organic farming system.
Chenopodium murale L. is an invasive weed species significantly interfering with wheat crop. However, the complete nature of its allelopathic influence on crops is not yet fully understood. In the present study, the focus is made on establishing the relation between plant morphophysiological changes and oxidative stress, induced by allelopathic extract. Phytotoxic medium of C. murale hairy root clone R5 reduced the germination rate (24% less than control value) of wheat cv. Nataša seeds, as well as seedling growth, diminishing shoot and root length significantly, decreased total chlorophyll content, and induced abnormal root gravitropism. The R5 treatment caused cellular structural abnormalities, reflecting on the root and leaf cell shape and organization. These abnormalities mostly included the increased number of mitochondria and reorganization of the vacuolar compartment, changes in nucleus shape, and chloroplast organization and distribution. The most significant structural changes were observed in cell wall in the form of amoeboid protrusions and folds leading to its irregular shape. These structural alterations were accompanied by an oxidative stress in tissues of treated wheat seedlings, reflected as increased level of H2O2 and other ROS molecules, an increase of radical scavenging capacity and total phenolic content. Accordingly, the retardation of wheat seedling growth by C. murale allelochemicals may represent a consequence of complex activity involving both cell structure alteration and physiological processes.
The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. The effects of allelopathic substances on competitive outcome when two species differ in their sensitivity to an inhibitor were modelled by applying atrazine, a commonly used herbicide for broadleaf weeds, to corn-soybean mixtures. A target-neighbor design was used, in which differing densities of a neighbor species are planted around one individual of the target species. This design is particularly appropriate to investigations of allelopathy, due to the density-dependent nature of phytotoxic effects. Neighbor density greatly influenced the response to the toxin. At corn densities of 0, 3, 6, 9, and 12 plants per pot and atrazine treatment of 3.0 mg/kg, the dry mass of the soybean (target) plant increased from 0.2 g with no neighbors to 0.5 g with 9-12 neighboring corn plants. The increased growth of soybean at higher corn densities is contrary to the predicted effects of resource competition and is due to uptake of atrazine by the corn plants, which decreased the amount available to the soybean target. Detoxification of soil by neighbors may explain in part the conflicting assessments of some putatively allelopathic species, such as black walnut (Juglans nigra).
Bioassays on Chenopodium murale demonstrated that root and shoot aqueous extracts reduced the seed germination, seedling establishment, plant growth and metabolite production of four target species. Leaf area and dry matter production showed a decreasing trend in response to the different treatments. Similar effects were found for pigment, carbohydrate and protein contents. In general, inhibition percentage was a function of extract concentration and plant tissue type. Shoot treatment was more strongly inhibitory than root treatment. The target species arranged from the most affected to the least affected were Melilotus indicus-Trifolium alexandrinum-Triticum pyramidal-Lycopersicon esculentum-Cucumis sativus.
Higher plants with strong allelopathic properties are commonly incorporated into soil for weed-control purposes. To understand the phytotoxic variation in the soil, which can be utilized for weed control through the use of allelopathic plants, the decomposition of alfalfa (Medicago sativa L. cv. Rasen) and kava (Piper methysticum L.) after soil amendment were evaluated. Both alfalfa and kava strongly inhibited barnyardgrass and monochoria growth for up to 10 days (80–100 % weed control). After 20–25 days, the magnitude of inhibition was drastically reduced, but was still effective (50 % weed control). A number of phenolic acids were detected in the soil even 50 days after incorporation in low concentration, but their concentrations reached a maximum after 10–15 days and were efficacious until 20–25 days. Phenolic acids varied between alfalfa and kava. The variations in electrical conductivity (EC) and osmotic pressure (OP) were strongly related to chemicals and toxic compounds exuded into the soil during decomposition and were proportional to the magnitude of inhibition observed, whereas pH did not appear to be correlated with inhibition. The decomposition of several unknown inhibitors present in kava was also analysed and assessed. Our findings indicate that these growth inhibitors were almost disintegrated in soil after 10 days, but strong inhibition was detected until 25 days after amendment. Results from this study demonstrate that chemicals released from allelopathic plants incorporated into soil are toxic and cause inhibition of certain species and could be exploited as a biological tool for weed management.
Alfalfa (Medicago sativa L.) plants were found to contain water-soluble substances that inhibited the germination and seedling growth of alfalfa (Chung and Miller 1990, Agron. J. 87, 762-767). Tsuzuki et al. (1999, Rep. Kyushu Branch Crop Sci. Soc. Japan 65, 39-40) discovered allelochemicals in alfalfa plants that could have adverse effects on the growth of some lowland weeds. This study was conducted to investigate varietal differences in allelopathic potential in alfalfa plants. Eight common varieties of Japanese alfalfa (Medicago sativa L.), namely Batasu, Hisawakaba, Kitawakaba, Makiwakaba, Natsuwakaba, Lucerne, Tachiwakaba and Yuba, were grown by conventional methods in the Experimental Field of the Crop Science Laboratory, Faculty of Agriculture, Miyazaki University. Aqueous extracts of both fresh and dried material of alfalfa plants of all varieties significantly inhibited both germination and growth of lettuce (Lactuca sativa L.). Leachates from germinating seeds of almost all alfalfa varieties inhibited elongation of the radicle but produced a negligible increase in germination and only slightly inhibited elongation of the hypocotyl of lettuce plants. Results demonstrated that the degree of inhibition of germination and growth of lettuce varied with the variety of alfalfa. In particular, Lucerne was identified as having the strongest allelopathic potential of the varieties studied. The results suggested that the allelopathic potential of alfalfa might be relating to a gene.
We discuss the dynamics of plant litter, the effects of litter on the chemical and physical environment, the direct and indirect effects of plant litter on plant populations and communities, and different adaptative traits that may be related to litter accumulation. The production of litter depends primarily on the site productivity, but other properties of the environment, as well as chance, may introduce important variation. The existence of time lags between the production of plant organs and their transformation into litter appears as a relevant character of litter dynamics seldom included in models. Herbivory, and other processes that destroy biomass or reduce productivity, may reduce the amount of litter produced. The destruction of litter encompasses a complex of interactions. The main processes, including physical and chemical degradation, consumption by invertebrates and decomposition, are differentially affected by the environment and by the physical and chemical characteristics of the litter itself. The relative importance of those processes varies among systems.
Garlic mustard (Alliaria petiolata, Brassicaceae) is an invasive, nonindigenous species currently invading the understory of North American woodlands where it is a serious threat to the native flora. Part of this success might be due to allelopathic interference by garlic mustard. Two congeneric species, the European Geum urbanum and the North American Geum laciniatum, were tested for allelopathic inhibition of germination by garlic mustard. Seeds were germinated either on substrate contaminated by garlic mustard or on substrate with contamination neutralized by activated carbon. Allelopathic effects of native European and invasive North American garlic mustard populations were also compared. Activated carbon increased germination by 14%, indicating that garlic mustard contaminated the substrate through root exudates. Activated carbon in turn counteracted this effect. The two test species differed in their sensitivity to allelopathic interference. North American G. laciniatum had a much stronger increase in germination when activated carbon was added to the substrate, independent of the origin of garlic mustard. In contrast, the European G. urbanum germinated better in substrate precultivated with North American garlic mustard, whereas activated carbon increased its germination only in substrate precultivated with European garlic mustard.
Natural regeneration of white spruce (Picea glauca) after disturbance has been reported to be very poor. Here a study was made to determine whether C compounds released from understorey species growing together with white spruce could be involved in this regeneration failure, either by (1) changing soil nutrient dynamics, (2) inhibiting germination, and/or (3) delaying seedling growth.
Foliage leachates were obtained from two shrubs (Ledum palustre and Empetrum hermaphroditum) and one bryophyte (Sphagnum sp.) with high phenolic compound concentrations that have been reported to depress growth of conifers in boreal forests, and, as a comparison, one bryophyte (Hylocomium splendens) with negligible phenolic compounds. Mineral soil from a white spruce forest was amended with plant leachates to examine the effect of each species on net N mineralization. Additionally, white spruce seeds and seedlings were watered with plant leachates to determine their effects on germination and growth.
Leachates from the shrubs L. palustre and E. hermaphroditum contained high phenolic compound concentrations and dissolved organic carbon (DOC), while no detectable levels of C compounds were released from the bryophytes Sphagnum sp. or H. splendens. A decrease in net N mineralization was determined in soils amended with L. palustre or E. hermaphroditum leachates, and this effect was inversely proportional to the phenolic concentrations, DOC and leachate C/N ratio. The total percentage of white spruce germination and the growth of white spruce seedlings were similar among treatments.
These results suggest that the shrubs L. palustre and E. hermaphroditum could negatively affect the performance of white spruce due to a decrease in soil N availability, but not by direct effects on plant physiology.
Extensive research work has been done on allelochemicals that are primarily plant secondary metabolites; in this review, some pathways of biosynthesis that are produced by higher plants are discussed as well as plant defense and the potential of the control of pests, diseases, and weeds. Benzoxazinoids, glucosinolates, and some sesquiterpenoids and phenolic compounds are discussed in more detail. Five genes, Bx1 through Bx5, have been analyzed and shown to be required for a typical benzoxazinoid, DIMBOA biosynthesis in maize, and their functions were demonstrated in vitro. Among those alleochemicals mentioned here, some isothiocyanates hirsutin and ω methylsulfonylalkyl (n=8, 9, and 10) isothiocyanates, sesquiterpenoids rugosal A and lettucenin A, and phenolic compounds emodin, physcion, p-hydroxybenzaldehyde, p-hydroxybenzoic acid, and oligostilbenes are emphasized from the viewpoint of plant defense.
Do stones modify the pore space in soil directly, or do they interact with the fine earth fraction? The contribution of each of these phases to porosity and water retention was analysed in mixtures of glass fragments < 6 mm with a silty‐clay soil and a clay soil in the 10–80% glass range. Each mixture was prepared wet and air‐dried before being saturated with water. Water contents were measured at matric suctions ranging from 0.05 to 1000 kPa, and the bulk densities were measured in air‐dry mixtures and at a matric suction of 0.5 kPa. The volume balance calculated by subtracting the pore volume due to soil fabric from the total pore volume of the mixtures shows that a variable proportion of porosity corresponded to coarse lacunar pores. The volume of the lacunar pores was affected little by the water content and generally increased from 0.01 to 0.21 cm ³ g ⁻¹ with increasing glass content but remained less than 0.01 cm ³ g ⁻¹ in silty‐clay soil mixtures with less than 50% glass. These coarse lacunar pores retained water at suctions < 10 kPa. They were determined by two kinds of mechanisms, i.e. filling in the case of the silty‐clay soil and shrinkage in the case of the clay soil. In these two cases there were two distinct types of pores in the mixtures: fine earth pores and coarse lacunar pores. A third mechanism, i.e. substitution, occurs in mixtures with large silty‐clay soil content, and determines the predominance of the fine earth pores. A clay content of 30% in the fine earth fraction and 50% fine earth in the mixture are threshold values proposed to predict pore space modifications induced by stones in soils.
Rôle des éléments grossiers dans la rétention en eau des sols
Résumé
Les éléments grossiers modifient‐ils directement l'espace poral du sol ou interagissent‐ils avec la terre fine? La contribution de chacune de ces phases sur la porosité et la rétention en eau est analysée sur des mélanges de verre pilé < 6 mm avec un sol argilo‐limoneux et un sol argileux dans la gamme de 10 à 80% de verre. Chaque mélange est préparéà l'état humide et séchéà l'air avant d'être saturé en eau. Les mesures sont réalisées entre 0,05 et 1000 kPa pour les teneurs en eau, à l'état sec à l'air et à la succion de 0,5 kPa pour les masses volumiques. Le bilan volumique montre qu'une part variable de la porosité correspond à des lacunes grossières. Leur volume, peu influencé par l'état hydrique, croît généralement de 0,01 à 0,21 cm ³ g ⁻¹ avec la teneur en verre mais reste inférieur à 0,01 cm ³ g ⁻¹ dans les mélanges du sol argilo‐limoneux avec moins de 50% de verre. Les lacunes grossières retiennent l'eau aux succions inférieures à 10 kPa. Ces lacunes sont déterminées par deux types de mécanismes, i.e. le remplissage avec le sol argilo‐limoneux et le retrait à la dessiccation avec le sol argileux. L'espace poral est dans ces deux cas constitué par deux types distinct de pores, les pores fins du sol et les lacunes grossières. Un troisième mécanisme, i.e. la substitution, intervient dans les mélanges riches en sol argilo‐limoneux et détermine la prédominance de la classe des pores fins. Un seuil de retrait correspondant à une teneur en argile de 30% dans le sol et une teneur de 50% de la phase sol dans le mélange sont retenus pour généraliser ces résultats.
The present study investigates the effect of residues of noxious weed Parthenium hysterophorus in soil as well as under laboratory conditions. Soils were infested with different amounts of Parthenium residues to determine the changes in soil chemistry, phenolic content and the phytotoxic effects on crops like chickpea (Cicer arietinum) and radish (Raphanus sativus). The modified soils and unmodified (control) soil were analyzed for pH, conductivity, organic carbon, organic matter, available nitrogen, phosphorus, potassium and micronutrients such as sodium, iron, manganese and zinc. The pH of all the modified soils decreased whereas the conductivity, organic carbon and organic matter increased. Further, the amount of sodium and potassium increased, whereas that of zinc decreased. In the soil infested with 4 g of Parthenium residue, the amount of available nitrogen decreased. The presence of significantly high amounts of phenolics in all modified soils indicated their possible interactions with soil chemical properties. This was also indicated by the correlation analysis between phenolics and various soil properties. The growth studies carried out in the modified soils indicated their phytotoxic nature, as seedling growth of both chickpea and radish was significantly decreased compared with seedlings grown in unmodified soils. The extracts prepared from Parthenium residues were also found to be phytotoxic to both the test crops and were also rich in phenolics. The presence of phenolics in Parthenium residues and their interference with soil chemistry upon release may be responsible for a decrease in the growth of radish and chickpea.
Methods for the quantitative analysis of anthocyanins, leuco-anthocyanins, flavanols and total phenols in plant tissue extracts are critically examined and suitable modifications of existing methods are described.
Summary •W e studied the effects of Cistus albidus leaf leachates on nitrogen-cycling pro- cesses in two siliceous soils (granite and schist) and one calcareous soil. We compared those effects with gross N-transformation rates in soils sampled underneath Cistus . • Soils amended with leachates and soils sampled under Cistus had higher NH 4 + immobilization and lower nitrification compared with control soils. Gross N mineral- ization increased under Cistus but decreased in soils amended with leachates. These effects were especially strong in granite soil. •T o determine whether phenolic compounds were causing those effects, we incub- ated granite soils with leachate and a leachate fraction containing only nonphenolic compounds. Nonphenolic compounds increased NH 4 + immobilization and decreased gross nitrification, while decreases in gross N mineralization were estimated to be caused by phenolic compounds. • Our results show that although phenolic compounds leached from green foliage changed gross N mineralization, their effects on net N rates were eclipsed by the changes produced by polar nonphenolic compounds such as carbohydrates. Plant nonphenolic compounds may drive N cycling under Cistus .
It is shown that litter of flowering plants of Cirsium vulgare inhibits the growth of seedlings of the same species at concentrations as low as 0.4% (g litter/g soil). The inhibition of growth cannot be fully compensated by adding nutrients, which indicates that autotoxicity may occur. It must be concluded, however, from an analysis of the results that immobilization of nutrients by microorganisms is the main cause of growth reduction if litter is added to the soil. In a field experiment under nutrient rich conditions plant litter did not affect germination, survival or growth of seedlings. The hypothesis is put forward that under conditions of nutrient deficiency and at high population densities, immobilization of nitrogen by Cirsium vulgare litter may influence plant growth. Results are discussed in relation to those of Stachon and Zimdahl (1980) and Wilson (1981) who claimed allelopathy for the related Cirsium arvense.
Reversible sorption of phenolic acids by soils may provide some protection to phenolic acids from microbial degradation. In the absence of microbes, reversible sorption 35 days after addition of 0.5–3 mol/g of ferulic acid or p-coumaric acid was 8–14% in Cecil Ap horizon and 31–38% in Cecil Bt, horizon soil materials. The reversibly sorbed/solution ratios (r/s) for ferulic acid or p-coumaric acid ranged from 0.12 to 0.25 in Ap and 0.65 to 0.85 in Bt horizon soil materials. When microbes were introduced, the r/s ratio for both the Ap and Bt horizon soil materials increased over time up to 5 and 2, respectively, thereby indicating a more rapid utilization of solution phenolic acids over reversibly sorbed phenolic acids. The increase in r/s ratio and the overall microbial utilization of ferulic acid and/or p-coumaric acid were much more rapid in Ap than in Bt horizon soil materials. Reversible sorption, however, provided protection of phenolic acids from microbial utilization for only very short periods of time. Differential soil fixation, microbial production of benzoic acids (e.g., vanillic acid and p-hydroxybenzoic acid) from cinnamic acids (e.g., ferulic acid and p-coumaric acid, respectively), and the subsequent differential utilization of cinnamic and benzoic acids by soil microbes indicated that these processes can substantially influence the magnitude and duration of the phytoxicity of individual phenolic acids.
The relative importance of allelopathy and resource competition in plant-plant interactions has been vigorously debated but seldom tested. We used activated carbon to manipulate the effects of root exudates of Centaurea maculosa, a noxious weed in much of western North America, on root elongation rates and growth of the native bunchgrass Festuca idahoensis in order to investigate the relative importance of allelopathy in the total interference of Centaurea. In root observation chambers, Festuca root elongation rates decreased to ᅢ% of the control, beginning 4 days before contacting Centaurea roots in silica sand. However, when activated carbon, which has a high affinity for adsorbing to organic compounds, was added to the sand the effects of Centaurea roots on Festuca root elongation were reduced. In other experiments, Festuca plants were 50% smaller when grown with Centaurea than with conspecifics in pure silica sand. However, Festuca grown with Centaurea in mixtures of sand and activated carbon were 85% larger than Festuca grown with Centaurea in silica sand without carbon. These results suggest that allelopathy accounts for a substantial proportion of the total interference of Centaurea on Festuca, shifting the balance of competition in favor of Centaurea. However, Centaurea outperformed Festuca even in the presence of activated carbon, demonstrating the importance of the combined roles of resource competition and allelopathy.
Previous research has shown that plant extracts, e.g. from boreal dwarf shrubs and trees, can cause reduced growth of neighbouring plants: an effect known as allelopathy. To examine whether arctic and subarctic plants could also be affected by leaching of phytochemicals, we added extracts from the commonly occurring arctic dwarf shrubs Cassiope tetragona and Empetrum hermaphroditum, and from mountain birch, Betula pubescens ssp. tortuosa to three graminoid species, Carex bigelowii, Festuca vivipara and Luzula arcuata, grown in previously sterilized or non-sterilized arctic soils. The graminoids in non-sterilized soil grew more slowly than those in sterilized soil. Excised roots of the plants in non-sterilized soil had higher uptake rate of labelled P than those in sterilized soil, demonstrating larger nutrient deficiency. The difference in growth rate was probably caused by higher nutrient availability for plants in soils in which the microbial biomass was killed after soil sterilization. The dwarf shrub extracts contained low amounts of inorganic N and P and medium high amounts of carbohydrates. Betula extracts contained somewhat higher levels of N and much higher levels of P and carbohydrates. Addition of leaf extracts to the strongly nutrient limited graminoids in non-sterilized soil tended to reduce growth, whereas in the less nutrient limited sterilized soil it caused strong growth decline. Furthermore, the N and P uptake by excised roots of plants grown in both types of soil was high if extracts from the dwarf shrubs (with low P and N concentrations) had been added, whereas the P uptake declined but the N uptake increased after addition of the P-rich Betula extract. In contrast to the adverse extract effects on plants, soil microbial respiration and soil fungal biomass (ergosterol) was generally stimulated, most strongly after addition of the Betula extract. Although we cannot exclude the possibility that the reduced plant growth and the concomitant stimulation of microbial activity were caused by phytochemicals, we believe that this was more likely due to labile carbon in the extracts which stimulated microbial biomass and activity. As a result microbial uptake increased, thereby depleting the plant available pool of N and P, or, for the P-rich Betula extract, depleting soil inorganic N alone, to the extent of reducing plant growth. This chain of events is supported by the negative correlation between plant growth and sugar content in the three added extracts, and the positive correlation between microbial activity, fungal biomass production and sugar content, and are known reactions when labile carbon is added to nutrient deficient soils.
Although the quantities of organic compounds exuding from roots is not large, seldom exceeding 0.4% of the carbon photosynthesized, they do exert a very strong influence on the soil microorganisms and may be significant in affecting plant nutrient availability. There is evidence that exudates from the roots of some plants are toxic to roots of neighboring plants and to the germination of some seeds.
Most of our information on root exudates has been obtained from solution-grown plants so that there are still some important questions to be answered about root exudates from soil-grown plants: (a) How much organic material is exuded from roots into soil? (b) How far from roots do the compounds diffuse? (c) What concentration gradients exist? (d) What effects do soil properties have upon exudation? (e) What are the main sites of exudation? The application of C14-labeling techniques offers a powerful tool with which to answer these questions. Use of radioisotopes to investigate the sites of exudation along roots and the role of lateral roots in the exudation process should enable us to determine what part of the soil will be most affected by root exudates.
It has now been demonstrated conclusively that application of certain compounds to leaves affects the quantity and types of exudates. The use of foliar sprays to modify root exudation has important implications in the fields of plant nutrition, root hygiene, and control of plant-plant interactions. Thus, we have before us an exciting field of study involving the combined efforts of plant physiologists, microbiologists, and soil scientists.
Plant roots serve a multitude of functions in the plant including anchorage, provision of nutrients and water, and production of exudates with growth regulatory properties. The root–soil interface, or rhizosphere, is the site of greatest activity within the soil matrix. Within this matrix, roots affect soil structure, aeration and biological activity as they are the major source of organic inputs into the rhizosphere, and are also responsible for depletion of large supplies of inorganic compounds. Roots are very complicated morphologically and physiologically, and their metabolites are often released in large quantities into the soil rhizosphere from living root hairs or fibrous root systems. Root exudates containing root-specific metabolites have critical ecological impacts on soil macro and microbiota as well as on the whole plant itself. Through the exudation of a wide variety of compounds, roots impact the soil microbial community in their immediate vicinity, influence resistance to pests, support beneficial symbioses, alter the chemical and physical properties of the soil, and inhibit the growth of competing plant species. In this review, we outline recent research on root exudation and the role of allelochemicals in the rhizosphere by studying the case of three plants that have been shown to produce allelopathic root exudates: black walnut, wheat and sorghum
In order to study the different soil organic matter mobilisation by agrarian (Zea mais: cultivars Paolo and Sandek) and forest (Picea abies Karst. and Pinus sylvestris L.) root exudates, three different soils (Dystric Spodic Cambisol--S1, Haplic Luvisol--S2 and Calcaric Cambisol--S3) have been considered. Treating the soils with water (control) or plant root exudates, soil organic matter extracts were obtained. The extracts were characterised by hormone-like activities and gas chromatographic/mass spectrometric (GC/MS) measurements. Water extract and plant root exudates exhibited no hormone-like activity, while the other soil-extracts were endowed with a different hormone-like behaviour. GC/MS data indicated that in the acid soils (S1) Sandek and Picea abies exudates showed a greater ability in extracting organic acid isomers (Cl4COOH, Cl5COOH and Cl7COOH), while in neutral soils (S3) all the exudates were active in separating organic acids. In intermediate conditions (S2), Picea abies and Pinus sylvestris exudates liberated C15COOH isomers, Paolo C11COOH isomers, while Sandek was not effective. The different role of plant root exudates in mobilising bio-molecules from the bulk of the soil is proposed.
Descriptive and experimental studies of desert shrub distributions have revealed important questions about the mechanisms by which plants interact. For example, do roots interact by mechanisms other than simple competition for limiting resources? We investigated this question using the desert shrubs Ambrosia dumosa and Larrea tridentata grown in chambers that allowed observation of roots during intraplant and intra- and interspecific interplant encounters. Two types of root "communication" were revealed. Ambrosia root systems appear to be capable of detecting and avoiding other Ambrosia root systems, whereas Larrea roots inhibit Larrea and Ambrosia roots in their vicinity.
The rhizosphere is a densely populated area in which plant roots must compete with invading root systems of neighboring plants for space, water, and mineral nutrients, and with other soil-borne organisms, including bacteria and fungi. Root-root and root-microbe communications are continuous occurrences in this biologically active soil zone. How do roots manage to simultaneously communicate with neighboring plants, and with symbiotic and pathogenic organisms within this crowded rhizosphere? Increasing evidence suggests that root exudates might initiate and manipulate biological and physical interactions between roots and soil organisms, and thus play an active role in root-root and root-microbe communication.
The root system of a plant is as complicated as the shoot in its diversity, in its reactions with the matrix of substances, and with the myriad organisms that surround it. Laboratory studies blind us to the complexity found by careful study of roots in soil. This complexity is illustrated in the much-studied corn root system, covering the changes along the framework roots: the surface tissues and their interactions with the soil, the water-conducting xylem, whose gradual elaboration dictates the water status of the root. A conspicuous manifestation of the changes is the rhizosheath, whose microflora differs from that on the mature bare zones. The multitude of fine roots is the most active part of the system in acquiring water and nutrients, with its own multitude of root tips, sites of intense chemical activity, that strongly modify the soil they contact, mobilize reluctant ions, immobilize toxic ions, coat the soil particles with mucilage, and select the microflora.
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