Articoli di riviste: "Plant growth inhibiting substances"

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Šimonová, E., M. Henselová e P. Zahradník. "Benzothiazole derivatives substituted in position 2 as biologically active substances with plant growth regulation activity". Plant, Soil and Environment 51, No. 11 (20 novembre 2011): 496–505. http://dx.doi.org/10.17221/3623-pse.

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Thirteen of the new synthetized 2-R substituted benzothiazole derivatives have been tested for plant growth regulatory (PGR) activity. The effect on growth elongation was studied on wheat coleoptile segments Triticum aestivum L. cv. Blava, and on the hypocotyl and roots in cucumber Cucumis sativum L. cv. Evita. The formation and number of adventitious roots and the length of hypocotyl in Vigna radiata (L.) Wilczek and, the effect on the length of stem, fresh and dry mass in buckwheat Fagopyrum esculentum Moench. cv. Pyra were evaluated. Cytokinin activity was determined on segments of barley leaves Hordeum vulgare L. cv. Jubilant on the basis of senescence inhibition and chlorophyll content. The benzothiazole derivatives were tested in the range of 10–3–10–7M concentrations, and PGR activity was compared with indole-3-acetic acid, indole-3-butyric acid and 6-furfurylaminopurine. All tested derivatives showed different auxine-like effects on elongation growth of plants and the stimulative effects were found to depend on applicable concentrations. At higher concentration rates, derivatives acted as growth retardants and inhibited the length of cucumber hypocotyl and roots. The derivatives increased the formation of adventitious roots of mung bean hypocotyl cuttings, as well as stem elongation and production of fresh and dry mass of buckwheat. Cytokinin activity was confirmed in one derivate only with a significant effect on the inhibition of leaf senescence and higher chlorophyll content. The tested benzothiazole derivatives may be characterized as biologically active substances with dominant auxine-like growth promoting activity

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Kremer, Robert J. "Antimicrobial Activity of Velvetleaf (Abutilon theophrasti) Seeds". Weed Science 34, n. 4 (luglio 1986): 617–22. http://dx.doi.org/10.1017/s0043174500067540.

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Velvetleaf (Abutilon theophrastiMedik. # ABUTH) seeds were bioassayed on 241 microbial isolates to assess their antimicrobial activity. Seeds placed on agar plates inoculated with test microorganisms released a diffusible substance(s) that inhibited the growth of 117 of 202 (58%) bacteria and all of the fungi tested. Antimicrobial activity of the seeds appeared to be nonselective as the extent of inhibition was not related to type of microorganism nor their origin. Hard, water-impermeable seeds had greater inhibitory activity than imbibed (soft) seeds. The intensity of inhibition was affected by prior leaching of seeds with various solvents and by the stage of seed development. Chemical analysis of diffusion zones from agar plates and seed leachates revealed the presence of phenolic compounds. The presence of antimicrobial substances in velvetleaf seeds may contribute to the persistence of viable seeds in soil by inhibiting potential seed-deteriorating microorganisms.

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Akshit K. Lohan, Ranjana Juwantha, Mohit Singh Bisht Jalaj Saxena e Pooja Kapoor. "Evaluation of Botanicals of Invasive Plant Species and Fungicides against Fungal Pathogens of Forest Nursery". International Journal of Current Microbiology and Applied Sciences 10, n. 9 (10 settembre 2021): 152–62. http://dx.doi.org/10.20546/ijcmas.2021.1009.018.

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Investigation of plants that possess natural antimicrobial substances for plant protection has been recognized as a promising disease management strategy. Alternaria alternata, Fusarium solani, Macrophomina spp., and Pestalotiopsis spp. isolated from diverse hosts such as Azadirachta indica, Melia dubia, Saraca indica and Quercus leucotrichophora produce important diseases in forest nurseries such as leaf blight, leaf spot, and wilt. In this study, botanicals from two invasive plant species, Ageratina adenophora and Ageratum conyzoides, were prepared and tested against plant diseases. Two botanicals (Methanolic extract obtained from the leaves of these two invasive species) and two fungicides were evaluated for their fungal growth inhibitory effects. At 1.5 percent concentration, the methanolic extract of Ageratina adenophora was found highly effective, inhibiting the growth of Macrophomina spp., (71.94%) followed by Pestalotiopsis spp. (70.20%), Alternaria alternate (51.92%) and Fusarium solani (47.03%). Whereas, Systemic chemical fungicide Thiophanate methylat 1.5% concentration showed maximum mycelial growth inhibition of Alternaria alternata (77.20%) and Macrophomina spp. (82.43%) and being deadlier to Pestalotiopsis spp. (100%) and Fusarium solani (100%). Their comparative analysis showed that higher doses of Ageratina adenophora caused either more or almost equal pathogen growth inhibition than lower doses of Chlorothalonil for certain fungi. Thus, promoting eco-friendly disease management strategies such as botanical control would be beneficial in reducing the need for pesticides.

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Anggraini, Fitri, Mieke Hemiawati Satari e Marry Siti Mariam. "Bacterial inhibition test of methanolic extracts of strawberry (Fragraia x ananassa Duchesne), lime (Citrus aurantifolia), and radish (Raphanus sativus L.), towards Streptococcus Sanguis ATCC 10556". Padjadjaran Journal of Dentistry 30, n. 2 (31 luglio 2018): 98. http://dx.doi.org/10.24198/pjd.vol30no2.18325.

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Introduction: Caries are initiated by the plaque formation on the tooth surface, due to the interaction between food debris and bacteria in the mouth. The pioneer bacterium of plaque formation is Streptococcus sanguis. The Strawberry fruit, lime fruit, and radish root are part of the plant that contains antibacterial substances. Flavonoid, tannin, saponin, alkaloid, polyphenol, terpenoid and quinon as antibacterial substances. This study aimed to evaluate strawberry fruit, lime fruit, and radish root methanol extract can inhibit Streptococcus sanguis ATCC 10556. Therefore, strawberry, lime, and radish can be made into mouthwash, bubble gum, or toothpaste to prevent plaque formation. Methods: This study used a Kirby-Bauer diffusion test as the inhibition test. Results: The result of this study that the biggest inhibition zone was lime methanol extract 20,000 ppm, and the smallest one was radish methanol extract 5,000 ppm. Conclusion: Strawberry fruit, lime fruit peel, and radish root methanol extract and their combination had the effect of inhibiting bacterial growth synergistically against Streptococcus sanguis ATCC 10556.

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Putri, Rury Eryna, Nisa Rachmania Mubarik, Laksmi Ambarsari e Aris Tri Wahyudi. "Antifungal Substances Produced by B. subtilis Strain W3.15 Inhibit the Fusarium oxysporum and Trigger Cellular Damage". HAYATI Journal of Biosciences 30, n. 5 (12 giugno 2023): 843–54. http://dx.doi.org/10.4308/hjb.30.5.843-854.

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Soybean Fusarium wilt and root rot disease caused by a necrotrophic ascomycete pathogen, F. oxysporum, triggered severe damage to the plant tissues and organs and impacted heavy losses. Biocontrol agents, Bacillus subtilis, were commonly used to produce a broad spectrum of antifungal substances and were gradually used in biocontrol studies for plant disease management. Investigation and determination of the inhibiting mechanism of antifungal substance produced by B. subtilis on F. oxysporum should be done to protect the soybean plant. This study revealed that basal nutrient broth (NB) gives the best antifungal activity. The stationary phase of the bacterial growth curve was obtained on two days of cultivation and showed the maximum antifungal activity against F. oxysporum. Ethyl acetate (EA) extraction of bacterial supernatant generated crude EA extract, which showed half inhibition (IC50) at 306.42 µg/ml obtained from the dose-response regression curve. Post-treatment mycelia of F. oxysporum with bacterial extract were demonstrated as hyphal deformation followed by malondialdehyde (MDA) accumulation. Furthermore, cellular leakage on fungal cells that may be triggered by antifungal compounds from strain W3.15 occurred. Last, the related antifungal compounds were predicted to be epicatechin and benzophenone from the LC-MS/MS analysis of crude EA extract. Accordingly, the biocontrol agent B. subtilis strain W3.15 promises a strong potency for biofungicide development.

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Paguirigan, Jaycee A., Rundong Liu, Seong Mi Im, Jae-Seoun Hur e Wonyong Kim. "Evaluation of Antimicrobial Properties of Lichen Substances against Plant Pathogens". Plant Pathology Journal 38, n. 1 (1 febbraio 2022): 25–32. http://dx.doi.org/10.5423/ppj.oa.12.2021.0176.

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Plant pathogens pose major threats on agriculture and horticulture, causing significant economic loss worldwide. Due to the continuous and excessive use of synthetic pesticides, emergence of pesticide resistant pathogens has become more frequent. Thus, there is a growing needs for environmentally-friendly and selective antimicrobial agents with a novel mode of action, which may be used in combination with conventional pesticides to delay development of pesticide resistance. In this study, we evaluated the potentials of lichen substances as novel biopesticides against eight bacterial and twelve fungal plant pathogens that have historically caused significant phytopathological problems in South Korea. Eight lichen substances of diverse chemical origins were extracted from axenic culture or dried specimen, and further purified for comparative analysis of their antimicrobial properties. Usnic acid and vulpinic acid exhibited strong antibacterial activities against Clavibacter michiganensis subsp. michiganensis. In addition, usnic acid and vulpinic acid were highly effective in the growth inhibition of fungal pathogens, such as Diaporthe eres, D. actinidiae, and Sclerotinia sclerotiorum. Intriguingly, the growth of Rhizoctonia solani was specifically inhibited by lecanoric acid, indicating that lichen substances exhibit some degrees of selectivity to plant pathogens. These results suggested that lichen substance can be used as a selective biopesticide for controlling plant disease of agricultural and horticultural significance, minimizing possible emergence of pesticide resistant pathogens in fields.

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Cesa-Luna, Catherine, Antonino Baez, Verónica Quintero-Hernández, Joel De la Cruz-Enríquez, Ma Dolores Castañeda-Antonio e Jesús Muñoz-Rojas. "The importance of antimicrobial compounds produced by beneficial bacteria on the biocontrol of phytopathogens". Acta Biológica Colombiana 25, n. 1 (1 gennaio 2020): 140–54. http://dx.doi.org/10.15446/abc.v25n1.76867.

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Bacteria produce antimicrobial compounds to compete for nutrients and space in a particular habitat. Antagonistic interactions can be evaluated by several methodologies including the double-layer agar and simultaneous inhibition assays. Among the well-known inhibitory substances produced by bacteria are the broad-spectrum antibiotics, organic acids, siderophores, antifungal, and bacteriocins. The most studied bacterial genera able to produce these inhibitory substances are Enterococcus, Lactococcus, Streptomyces, Bacillus, Pseudomonas, Klebsiella, Escherichia, and Burkholderia. Some beneficial bacteria can promote plant growth and degrade toxic compounds in the environment representing an attractive solution to diverse issues in agriculture and soil pollution, particularly in fields with damaged soils where pesticides and fertilizers have been indiscriminately used. Beneficial bacteria may increase plant health by inhibiting pathogenic microorganisms; some examples include Gluconacetobacter diazotrophicus, Azospirullum brasilense, Pseudomonas fluorescens, Pseudomonas protegens, and Burkholderia tropica. However, most studies showing the antagonistic potential of these bacteria have been performed in vitro, and just a few of them have been evaluated in association with plants. Several inhibitory substances involved in pathogen antagonism have not been elucidated yet; in fact, we know only 1 % of the bacterial diversity in a natural environment leading us to assume that many other inhibitory substances remain unexplored. In this review, we will describe the characteristics of some antimicrobial compounds produced by beneficial bacteria, the principal methodologies performed to evaluate their production, modes of action, and their importance for biotechnological purposes.

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Islam, A. K. M. Mominul, Osamu Ohno, Kiyotake Suenaga e Hisashi Kato-Noguchi. "Suaveolic Acid: A Potent Phytotoxic Substance ofHyptis suaveolens". Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/425942.

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Hyptis suaveolens(Lamiaceae) is an exotic invasive plant in many countries. Earlier studies reported that the aqueous, methanol, and aqueous methanol extract ofH. suaveolensand its residues have phytotoxic properties. However, to date, the phytotoxic substances of this plant have not been reported. Therefore, the objectives of this study were isolation and identification of phytotoxic substances ofH. suaveolens. Aqueous methanol extract of this plant was purified by several chromatographic runs through bioassay guided fractionation using garden cress (Lepidium sativum) as a test plant. Final purification of a phytotoxic substance was achieved by reverse phase HPLC and characterized as 14α-hydroxy-13β-abiet-8-en-18-oic acid (suaveolic acid) by high-resolution ESI-MS,1H-,13C-NMR, CD, and specific rotation. Suaveolic acid inhibited the shoot growth of garden cress, lettuce (Lactuca sativa), Italian ryegrass (Lolium multiflorum), and barnyard grass (Echinochloa crus-galli) at concentrations greater than 30 µM. Root growth of all but lettuce was also inhibited at concentrations greater than 30 µM. The inhibitory activities were concentration dependent. Concentrations required for 50% growth inhibition of suaveolic acid for those test plant species were ranged from 76 to 1155 µM. Therefore, suaveolic acid is phytotoxic and may be responsible for the phytotoxicity ofH. suaveolensplant extracts.

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Safni, Irda, e Widya Antastia. "In vitro antagonism of five rhizobacterial species against athelia rolfsii collar rot disease in soybean". Open Agriculture 3, n. 1 (1 agosto 2018): 264–72. http://dx.doi.org/10.1515/opag-2018-0028.

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Abstract Plant Growth Promoting Rhizobacteria (PGPR) influence plant growth by a number of direct (producing plant growth promoting substances) and indirect (through prevention of deleterious effects of phytopathogenic microorganisms) mechanisms. Five species of bacteria were isolated from rhizospheric soils of soybean and peanut fields from several locations in North Sumatra. On the basis of morphological and biochemical characteristics, the bacteria were identified as Aeromonas hydrophila, Burkholderia cepacia, Serratia ficaria, Pantoea spp. 2, and Vibrio alginolyticus. These species were tested in vitro against the causal pathogen of collar rot disease of soybean, Athelia rolfsii, which is an important soybean disease in Indonesia. The five species of bacteria were subjected to screening of antagonistic activities against A. rolfsii in vitro with a dual culture-technique. Of the five species, B. cepacia, S. ficaria and V. alginolyticus were the most effective antagonistic bacteria to control A. rolfsii. B. cepacia, S. ficaria and V. algynolitycus produced inhibiting zones against A. rolfsii of 98.35%, 97.83% and 96.97% respectively. All bacterial species showed their antagonistic activity significantly with the inhibiting zone percentage being more than 60%. The experimental results suggested that all bacterial species have a future potency as a biocontrol agent to reduce A. rolfsii collar rot disease of soybean

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Robert, Jean-Claude, e Jean-Paul Bret. "Release of an inhibitor of stipe elongation from illuminated caps of Coprinus congregatus mushrooms". Canadian Journal of Botany 65, n. 3 (1 marzo 1987): 505–8. http://dx.doi.org/10.1139/b87-063.

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Inhibition of stipe growth by a substance or substances produced in the cap of Coprinus congregatus fruit bodies cultivated in continuous light has been confirmed. Caps in which maturation was induced or prevented were transferred to decapitated stipes from normally growing sporophores. Stipes were most sensitive to inhibition when treated 16–18 h before maturity. Caps from continuous-light primordia only a few hours older than the photoinhibited stage were most inhibitory. When normal primordium maturation was induced by darkness followed by light, the inhibitor disappeared from the caps 18–20 h before maturity.

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Epstein, James, Edward J. Desjardins, Peter L. Hudson e Patricia K. Donahoe. "Stainless steel mesh supports high density cell growth and production of recombinant Mullerian Inhibiting Substances". In Vitro Cellular & Developmental Biology 25, n. 2 (febbraio 1989): 213–16. http://dx.doi.org/10.1007/bf02626181.

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Sofyanita, Eko Naning, e Roni Afriansya. "DIFFERENCES OF INHIBITION ZONE FOREST PURE HONEY AND CINNAMON (Cinnamomum burmani) AS ANTIBACTERIAL BACTERIAL COMPOUNDS OF MEMBERS OF THE Enterobacteriaceae FAMILY". Jurnal Riset Kesehatan 10, n. 1 (28 maggio 2021): 7–11. http://dx.doi.org/10.31983/jrk.v10i1.6424.

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Honey and cinnamon are plant products that have many properties, one of which is used as an antibacterial agent for various diseases. The effectiveness of the two active substances against bacteria in the Enterobacteriaeae family is unclear. The study was conducted to determine the differences in the effectiveness of forest honey and cinnamon in inhibiting the growth of bacteria in the Enterobacteriaceae family. This research method is an experimental study with a combination method of diffusion and wells using samples of the bacteria Klebsiella pneumoniae, Esherichia coli, Salmonella typhi, Serratia marcescens, and Enterobacter cloacae. Forest pure honey and cinnamon were prepared as test solutions with concentrations of 25%, 40%, 55%, 70%, 85% and 100%. The results obtained were the inhibition zone formed on Nutrient Agar Plate (NAP) media, in forest pure honey the inhibition zone formed in S. typhi, E. coli, Klebsiella pneumoniae, Serratia marcescens, and Enterobacter cloacae was greater at 100% concentration, namely 30.5mm, 32.5mm, 38mm, 29.5mm, 26mm, while the 100% concentration of cinnamon showed results, namely 12mm, 10mm, 8.5mm, 11mm, and 11mm. Conclusion is Forest pure honey was more effective at inhibiting bacteria from the Enterobacteriaceae family than cinnamon.

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Raskil’dina, Gul’nara Z., Yulianna G. Borisova, Natalia N. Mikhaiylova, Semyon S. Zlotskiy, Louise M. Mryasova e Vyacheslav M. Kuznetsov. "PLANT GROWTH REGULATORS BASED ON CYCLIC KETALS AND THEIR DERIVATIVES". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, n. 1 (1 marzo 2017): 95. http://dx.doi.org/10.6060/tcct.2017601.5475.

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For citation:Raskil’dinaG.Z., BorisovaY.G., MikhailovaN.N., MryasovaL.M., KuznetsovV.M., ZlotskiyS.S. Plant growth regulators based on cyclic ketals and their derivatives. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 1. P. 95-101.Low toxicity of polyfunctional 1,3-dioxocyclicalkanes to soil bacteria allows to consider the compounds of this class as perspective herbicides. In this regard, we studied the herbicidal activity of a series of substituted cyclic ketals, their derivatives and alkenylmalonates. On the basis of commercially available triols the corresponding cyclic ketals were obtained with a yield more than 90%. O-alkylation of alcohol according to the methods led to the corresponding ethers and esters. The glycerol monoethers were obtained quantitatively by acid hydrolysis of ketals. Growth-regulatory activity of the synthesized compounds was determined in vitro on wheat and pea seedlings according to a known procedure (aromatic solvent - nefras A 150/330, surfactant - oxyethylated izononilfenol neonol AF-9-12). Evaluation of herbicidal activity of preparations was carried out in the laboratory. During 3 days length (L, mm) and weight (m, g) seedlings in comparison with the control option was measured. Without herbicide on seedlings the monocotyledonous and dicotyledonous plants are placed in Petri dishes containing water emulsion of active substances with a concentration of 5 mg / l and 10 mg / l for peas and 50 mg / l and 100 mg / l for wheat. As a reference well-known herbicide, Oktapon Extra, was used. The diol with allyloxy-diol group showed the best results towards wheat. This compound successfully inhibits the increase in the length and weight of escape and gives close results to the standard. For peas, ketals and derivatives thereof are effective only in terms of inhibition of the shoot masses. Heterocyclic alcohol and glycols are superior to the standard, and a ketal at a concentration of 10 mg / l practically corresponds to it. Alkenylmalonates were more effective in inhibiting the escape weight wheat than peas. In particular, at a concentration of 100mg / l effectiveness of methallyl derivatives of trans-1,3-dichloropropene coincides to the standard. Physical and chemical characteristics of the compounds were proved by NMR and mass spectra. Screening results showed that activity of diol with allyloxy group is close to the ideal attitude to wheat. Ketals and their derivatives show the herbicidal activity only at inhibition of the mass escape of peas. Results of alkenylmalonates were better at inhibition of the mass escape of wheat than peas. The obtained results prove prospectivity of producing of herbicidal drugs based on the alkenylmalonates substituted diols and acetals, as a new generation of herbicides.

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Chowdhury, Pranami, Shamim Shamsi e Md Abul Bashar. "Antagonistic potential of soil fungi as biocontrol agent against rice pathogens". Bangladesh Journal of Botany 53, n. 1 (31 marzo 2024): 101–8. http://dx.doi.org/10.3329/bjb.v53i1.72246.

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Antagonistic potential of six soil fungi viz., Aspergillus flavus Link., A. fumigatus Fresen., A. niger Tiegh., Penicillium sp., Trichoderma harzianum Refat. and T. viride Pers. against eight pathogenic fungi viz., Alternaria alternata (Fr.) Keissler, Curvularia lunata (Wakker) Boedijn, Drechslera oryzae Breda de Haan (Subramanian and Jain), Fusarium moniliforme Sheldon, F. solani (Mart.) Sacc. Microdochium oryzae (Hashloka and Yokogi) Sam. and Hal., Pestalotiopsis guepinii (Desm.) Stay. and Sarocladium oryzae (Sawada) W. Gams and D. Hawks of rice were evaluated. In colony interaction, the highest growth inhibition (88%) was observed owing to T. harzianum against Alternaria alternata.Volatile substances from soil fungi inhibited the radial growth of the test pathogens which varied from 8.33 to 57.36%.The highest inhibition (57.36%) was found owing to T. harzianum against P. guepinii. The inhibition of mycelial growth of the test pathogens ranged from 29.05 to 64.5% owing to non volatile substances of the soil fungi. The highest mycelial growth inhibition was observed owing to T. harzianum against C. lunata. Trichoderma harzianum may be exploited commercially to control rice pathogens. Bangladesh J. Bot. 53(1): 101-108, 2024 (March)

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Sahu, Anita, e Anjana Devkota. "ANTIMICROBIAL ACTIVITY OF LEAF EXTRACTS OF SOME INVASIVE ALIEN PLANT SPECIES OF ASTER FAMILY AGAINST CLINICAL BACTERIA". Ecoprint: An International Journal of Ecology 23 (5 dicembre 2016): 1–12. http://dx.doi.org/10.3126/eco.v23i0.20646.

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Aqueous and methanolic extracts of three plants at four different concentration viz. at 50, 100, 150 and 200 mg/ml were tested on clinical bacteria using the disc diffusion method. In vitro antibacterial activity was screened by using Nutrient Agar (NA). The qualitative phytochemical analysis depicted the presence of terpenoids, saponins, alkaloids, flavonoids, carotenes and glycosides in the plants. Results showed broad spectrum antimicrobial activity against the Gram-negative and Gram-positive bacteria. The methanol extract inhibited the growth of more bacteria compared to the aqueous extract. Results from in vitro study revealed that the antimicrobial activity might have been influenced by the solubility of active compound(s) in extracting solvent. Methanol extracts were relatively more effective than aqueous extract. Out of three invasive plants studied Parthenium hysterophorus seemed more effective, for inhibiting the growth of bacterial strains with maximum zone of inhibition (24.85 mm diam.), shown against Enterococcus faecalis at a concentration of 200 mg/ml. The demonstration of activity against all these organisms had shown that all three alien invasive species; Ageratum haustonianum, Mikania micrantha and Parthenium hysterophorus can be used to produce raw materials/substances for further development of diverse antibiotics with broad spectrum of activity.ECOPRINT 23: 1-12, 2016

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Voropaeva, N., V. Karpachev, V. Varlamov e Oleg L. Figovsky. "Influence of Efficient, Multicomponent, Polyfunctional, Physiologically Active (Nano) Chips with Herbicide Activity on Rice Crop Growth, Development, Yield and on Weed Growth Inhibition". International Letters of Chemistry, Physics and Astronomy 26 (gennaio 2014): 62–68. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.26.62.

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Using physiologically active, complex, polyfunctional, multicomponent (nano) systems – (nano) chips in the pre-sowing rice treatment (nano) technology allows precise seeding; enhancing field seed germination; reducing plant morbidity rate considerably or even deleting disease incidents; increasing plant adaptability to unfavorable environmental conditions; expanding crop yield; improving products quality by not using toxic chemical means of plant protection; intensifying competitive ability of agricultural products as well as assuring environmental safety in crop cultivation regions. Nutrition micro- and mesoelements, as also intense activity plant growth regulators and other physiologically active substances, depending on the crop variety, cultivation conditions and possible risks, can be added to such pre-sowing treatment (nano) technology.

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Voropaeva, N., V. Karpachev, V. Varlamov e Oleg L. Figovsky. "Influence of Efficient, Multicomponent, Polyfunctional, Physiologically Active (Nano) Chips with Herbicide Activity on Rice Crop Growth, Development, Yield and on Weed Growth Inhibition". International Letters of Chemistry, Physics and Astronomy 26 (24 gennaio 2014): 62–68. http://dx.doi.org/10.56431/p-f9n4d0.

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Using physiologically active, complex, polyfunctional, multicomponent (nano) systems – (nano) chips in the pre-sowing rice treatment (nano) technology allows precise seeding; enhancing field seed germination; reducing plant morbidity rate considerably or even deleting disease incidents; increasing plant adaptability to unfavorable environmental conditions; expanding crop yield; improving products quality by not using toxic chemical means of plant protection; intensifying competitive ability of agricultural products as well as assuring environmental safety in crop cultivation regions. Nutrition micro- and mesoelements, as also intense activity plant growth regulators and other physiologically active substances, depending on the crop variety, cultivation conditions and possible risks, can be added to such pre-sowing treatment (nano) technology.

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Gubó, Eduárd, Ildikó Kiss-Szarvák, Mishele Erdenebaatar, Richárd Gubó, Bence Horváth, Pál Szakál e Judit Plutzer. "Ecotoxicological investigations of milking cow slurry and changes of oestrogenic compounds in the solid and liquid phase". Energy, Ecology and Environment 7, n. 2 (15 novembre 2021): 97–110. http://dx.doi.org/10.1007/s40974-021-00234-1.

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AbstractDue to the appearance of intensive livestock-rearing systems since the 1970s, a vast amount of liquid manure (slurry) has been produced. The application and utilization are partly regulated for this special substance, which contains urine, excrement, process water, and other chemicals, such as insecticides and disinfectants. Our research was conducted on a slurry management system of a dairy cattle farm, focusing on the investigation of the presence of oestrogenic substances and toxicity of slurry before and after using a separator technology. Yeast oestrogen screen shows in this study that the separation of the liquid and solid phases of slurry contributes to the reduction in oestrogenic substances. Based on the toxicological studies, the growth inhibition of algae was 93%, and the inhibition of the germination of higher plant seeds was 25%, without separation. After separation of the phases, growth and germination were comparable with the negative control; moreover, some stimulation was detected. Consequently, harmful substances were removed with the suspended solid phase. From the present study, we can conclude that stakeholders should support separation technology in intensive livestock-rearing systems, and ecotoxicological investigations obviously help the risk management of slurry utilization. To our best knowledge, this is the first paper presenting detailed and complex toxicological study on slurry samples.

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Moh, Seinn Moh, Naoaki Kurisawa, Kiyotake Suenaga e Hisashi Kato-Noguchi. "Allelopathic Potential of Marsdenia tenacissima (Roxb.) Moon against Four Test Plants and the Biological Activity of Its Allelopathic Novel Compound, 8-Dehydroxy-11β-O-Acetyl-12β-O-Tigloyl-17β-Marsdenin". Plants 12, n. 8 (15 aprile 2023): 1663. http://dx.doi.org/10.3390/plants12081663.

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Plant parts and extracts that are rich in bioactive substances with allelopathic potential can be explored as a possible alternative to herbicides for natural weed control in sustainable agriculture. In the present study, we investigated the allelopathic potential of Marsdenia tenacissima leaves and its active substances. Aqueous methanol extracts of M. tenacissima showed significant inhibitory activities against the growth of lettuce (Lactuca sativa L.), alfalfa (Medicago sativa L.), timothy (Phleum pratense L.), and barnyard grass (Echinochloa crusgalli (L.) Beauv.). The extracts were purified through various chromatography steps, and one active substance was isolated and determined by spectral data to be a novel compound, assigned as steroidal glycoside 3 (8-dehydroxy-11β-O-acetyl-12β-O-tigloyl-17β-marsdenin). Steroidal glycoside 3 significantly inhibited the seedling growth of cress at a concentration of 0.03 mM. The concentrations needed for 50% growth inhibition of the cress shoots and roots were 0.25 and 0.03 mM, respectively. These results suggest that steroidal glycoside 3 may be responsible for the allelopathy of M. tenacissima leaves.

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Nedeva, D., S. Petkova, Y. Angelova e L. Iliev. "The effect of plant growth regulators and chlorsulfuron on electrophoretic profiles of soluble proteins, polypeptides and antioxidant enzymes in maize seedlings". Plant, Soil and Environment 51, No. 2 (19 novembre 2011): 87–93. http://dx.doi.org/10.17221/3560-pse.

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Investigations were carried out with maize (Zea mays L.) seedlings. The effect of chlorsulfuron (CHF) on the electrophoretic profiles of the total and thermostable proteins, polypeptides and some antioxidant enzymes was compared to the effect of abscisic acid (ABA), benzylaminopurine (BAP) and N1-(2-chloro-4-pyridyl)-N2-phenylurea (4PU-30) applied in concentrations that inhibit the growth of seedlings. It was established that the effect of CHF on seedling growth as well as on the studied biochemical parameters was most significant. The reduction of growth by CHF was accompanied by a significant decrease in the quantity of main proteins and specific qualitative changes in the electrophoretic patterns for coleoptiles. The appearance of a new native protein with Rm 0.22 and polypeptide with MW 67 kDa was demonstrated. Some similarity of the effect on protein band with Rm value 0.22 was observed under the influence of 4PU-30 as well. In the endosperm the effect of CHF was manifested as a delay of degradation. CHF and 4PU-30 influenced the activity of basic peroxidases in the opposite manner. The strong inhibiting effect of both cytokinins BAP and 4PU-30 on the activity of slow migrating superoxide dismutase (SOD) isoenzymes was observed. Each of the tested substances shows a differential effect on the proteins and antioxidant enzymes, despite the fact that all of them were applied at concentrations that inhibit the growth of seedlings.

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21

Lun, Thang Lam, Shunya Tojo, Toshiaki Teruya e Hisashi Kato-Noguchi. "Allelopathic Activity of the Invasive Plant Polygonum chinense Linn. and Its Allelopathic Substances". Plants 12, n. 16 (17 agosto 2023): 2968. http://dx.doi.org/10.3390/plants12162968.

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Polygonum chinense Linn., belonging to the Polygonaceae family, is distributed mostly in northern temperate climates. This species is a high-risk invasive plant and is thought to possess allelopathic potential. This study aimed to isolate and identify the allelopathic substances from P. chinense. Aqueous methanol extracts of P. chinense significantly inhibited the growth of alfalfa and Italian ryegrass seedlings in a species- and concentration-dependent manner. Activity-guided fractionation led to the isolation of two active compounds: dehydrovomifoliol and loliolide. A cress bioassay was used to determine the biological activity of dehydrovomifoliol, and cress, alfalfa, and Italian ryegrass were used to determine loliolide. Dehydrovomifoliol significantly suppressed the seedling growth of cress at the concentration of 1 mM, and the concentrations necessary for 50% growth inhibition (I50 values) of the roots and shoots were 1.2 and 2 mM, respectively. Loliolide significantly suppressed the shoot growth of cress, alfalfa, and Italian ryegrass at the concentration of 1 mM, and the concentrations necessary for I50 values of the shoots and roots were 0.15 to 2.33 and 0.33 to 2.23 mM, respectively. The findings of our study suggest the extracts of P. chinense might have growth-inhibitory potential and that dehydrovomifoliol and loliolide might contribute as allelopathic agents.

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22

Wang, Enzhao, Xiongduo Liu, Zhiyuan Si, Xu Li, Jingjing Bi, Weiling Dong, Mingshun Chen et al. "Volatile Organic Compounds from Rice Rhizosphere Bacteria Inhibit Growth of the Pathogen Rhizoctonia solani". Agriculture 11, n. 4 (19 aprile 2021): 368. http://dx.doi.org/10.3390/agriculture11040368.

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Rice sheath blight, a fungal disease caused by Rhizoctonia solani, seriously threatens rice production. Some of the volatile organic compounds (VOCs) produced by microbes are inhibitory to the growth of the plant pathogen, and hence may have the potential as environmentally friendly antifungal substances. However, information on the inhibitory effect of VOCs released by rice rhizosphere bacteria on R. solani is scarce. In this study, bacteria from the rice rhizosphere capable of inhibiting the growth of R. solani via releasing VOCs were screened using a double Petri dish assay. Headspace solid phase microextraction and gas chromatography mass spectrometry (GC/MS) were used to identify and quantify the VOCs. The contributions of VOCs to the inhibition of the growth of R. solani were estimated by constructing a random forest model, and were verified using pure compounds. Nine strains (i.e., Pseudomonas sp. No. 3, Enterobacter sp. No. 26, Enterobacter sp. No. 34, Pseudomonas sp. No. 35, Ralstonia sp. No. 50, Bacillus sp. No. 62, Arthrobacter sp. No. 146, Brevibacillus sp. No. 2–18, and Paenisporosarcina sp. No. 2–60) showed various inhibition on R. solani growth via VOCs. The inhibitory effect ranged from 7.84% to 100%, with Ralstonia sp. No. 50 completely inhibiting the growth of R. solani. Five VOCs (i.e., benzoic acid ethyl ester, 3-methyl-butanoic acid, 2-ethyl-1-hexanol, 3-methyl-1-butanol, and 6-methyl-5-hepten-2-one) identified by random forest model were confirmed to be toxic to R. solani when applied as a pure chemical compound. In particular, benzoic acid ethyl ester, 3-methyl-butanoic acid, and 2-ethyl-1-hexanol were lethal to R. solani. In summary, the rice rhizosphere bacteria (Ralstonia sp. No. 50) and VOCs (benzoic acid ethyl ester, 3-methyl-butanoic acid, and 2-ethyl-1-hexanol) showed potential to be used as new resources for biological control of rice sheath blight.

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23

Anita, Anita, Andi Fatmawati, Tuty Widyanti, Rahmawati Rahmawati e Putri Ahmad. "Activity Test of Kedondong Leaf Juice Extract (Spondias dulcis) as Anti-Candida albicans in Patients with Diabetes Mellitus". Lontara Journal of Health Science and Technology 4, n. 2 (15 dicembre 2023): 140–48. http://dx.doi.org/10.53861/lontarariset.v4i2.418.

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Diabetes is a disease characterized by high blood glucose levels which can stimulate the growth of the Candida albicans. Indonesia is the second highest country in the world with biodiversity which allows the creation of new compounds that can be used as medicine. One type of plant that has medicinal properties is kedondong leaves (Spondias dulcis) which can be used as herbal medicine, and can also act as an anti-fungal, because it has anti-fungal substances such as flavonoids, alkaloids, saponins and tannins. This compound can prevent fungal growth. The aim of this research was to determine the inhibitory ability of kedondong (Spondias dulcis) leaf extract in inhibiting the growth of Candida albicans using the Kirby Bauer method. The type of research used in this research is laboratory experiments. The results of the inhibition test in this study were the concentration inhibition zone results of 25%, 50%, 75%, 100%, the results were 0 mm, indicating that these 4 concentrations could not inhibit the growth of Candida albicans. Meanwhile, the positive control showed that there was a clear zone with an average of 28.8 mm, which indicated that antibiotics inhibited the growth of Candida albicans, while the negative control showed that no clear zone was formed. Therefore, the results of this study can be concluded that squeezed kedondong (Spondias dulcis) leaf extract cannot inhibit the growth of Candida albicans isolated from diabetes mellitus sufferers

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24

Liang, Dong, Shengnan Liu, Miaoyun Li, Yaodi Zhu, Lijun Zhao, Lingxia Sun, Yangyang Ma e Gaiming Zhao. "Effects of Different Bacteriostats on the Dynamic Germination of Clostridium perfringens Spores". Foods 12, n. 9 (28 aprile 2023): 1834. http://dx.doi.org/10.3390/foods12091834.

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Bacteriostats, as chemical substances that inhibit bacterial growth, are widely used in the sterilization process; however, their effects on spindle spores are unclear. In this study, the effects of bacteriostats, including nine commonly used food additives and four detergents, on the growth of Clostridium perfringens spores were investigated. The results showed that 0.07‰ ethylenediaminetetraacetate had a good inhibitory effect on C. perfringens spore growth, and the spore turbidity decreased by 4.8% after incubation for 60 min. Furthermore, 0.3‰ tea polyphenols, 0.8‰ D-isoascorbic acid, and 0.75‰ potassium sorbate promoted leakage of contents during spore germination. Among the four detergents, 5‰ glutaraldehyde solution presented the best inhibitory effect on the growth of C. perfringens spores, and the spore turbidity decreased by 5.6% after incubation for 60 min. Further analysis of the inactivation mechanism of spores by the bacteriostats was performed by comparing the leakage of UV-absorbing substances during germination. The results revealed that bacteriostats could not directly kill the spores, but could inactivate them by inhibiting germination or damaging the spore structure during germination, thus preventing the formation of bacterial vegetative bodies. These findings provide important information and reference for the mechanism underlying the effects of different bacteriostatic agents on spore growth.

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25

Shafeeq, Ahmed Fawzi, Idham Ali Abed e Abdullah Abdulkareem Hassan. "Evaluation of The Efficiency of Some Desert Plant Extracts in The Growth of Agaricus Bisporus and The Inhibition of Some of Its Pathogens". IOP Conference Series: Earth and Environmental Science 910, n. 1 (1 novembre 2021): 012113. http://dx.doi.org/10.1088/1755-1315/910/1/012113.

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Abstract Seven isolates of Pseudomonas spp. were isolated from the casing soil and 11 fungal isolates were isolated from the spent compost in the Mushroom Farm - College of Agriculture - Tikrit University. According to the pathogenicity test against Agaricus bisporus fruit bodies, the results showed that the highest infection rate was recorded in the bacterial isolate 1077by 77.45%, while the fungal isolate 1076 showed the highest pathogenicity against Agaricus bisporus fruit bodies by recording the highest infection rate reached to 81.23%. The pathogenic bacteria and fungi isolates were phenotypically identified to the species level as Pseudomonas tolaasii and Trichoderma harzianum, respectively. The results showed the alcoholic extracts of Atriplex tatarica and Haloxylon salicornicum were superior in the active substances compared to other extracts, the highest percentage of total alkaloids, tannins, saponins, phenols and flavonoids was 35.14, 44.79, 43.47, 32.05 and 31.66 mg/g in the alcoholic extract of A. tatarica, respectively, while the alcoholic extract of H. salicornicum had the highest percentage of glycosides, which amounted to 41.89 mg/g of the extract. The highest efficiency of A. tatarica alcoholic extract in inhibiting the pathogenic fungus T. harzianum, was recorded, as the colony diameter was 3.1 cm in concentration of 4 mg/mL compared to 8.9 cm in the control treatment, while the H. salicornicum alcoholic extract was superior in inhibiting the pathogenic bacteria at the same concentration, in which the inhibition zone was 15.67 mm compared to no inhibition in the control treatment. While there was little effect of alcoholic extracts of both plants on the growth of A. bisporus. The results of the dry powders effect for both plants showed that the highest inhibition against the pathogenic fungus T. harzianum was recorded by the A. tatarica powder at 2% concentration, reaching 5.01 cm, while the H. salicornicum powder showed the highest inhibition against the bacteria P.tolaasii at the same concentration in which the number of cells reached to 3.23 x 107 cells/mL compared to 6.6 x 107 cells/mL in the control treatment. The results also showed the highest growth of A. bisporus that reached 9 cm for all powdered concentrations of both plants.

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26

Rasyid, Andi Ulfah Magefirah, e Zahira Amody. "PENGUJIAN EFEKTIFITAS FORMULA GEL EKSTRAK DAUN BELUNTAS (Pluchea indica (L.) Less) DENGAN VARIASI KONSENTRASI GELLING AGENT SEBAGAI KANDIDAT SEDIAAN ANTI JERAWAT". Jurnal Ilmiah Manuntung 6, n. 2 (30 dicembre 2020): 312. http://dx.doi.org/10.51352/jim.v6i2.393.

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Beluntas (Pluchea indica (L.) Less) is a plant that is often used in traditional medicine because of the presence of several substances that have activity as antimicrobial compounds. Beluntas leaves contain secondary metabolite compounds such as flavonoids, alkaloids, tannins, steroids, terpenoids and saponins which can function as antibacterial. This experimental research aimed at obtaining beluntas leaf extract gel and to determine the physical stability and the effectiveness of beluntas extract gel against Propionibacterium acnes. The first step is drying the beluntas leaves and and extracted by maceration method with 70% ethanol solvent. The extract obtained was then formulated into a gel and evaluated, the evaluation results show that formula 1 is the most stable. The results showed that beluntas leaf extract gel was effective in inhibiting the growth of Propionibacterium acnes, the inhibition zone obtained was categorized as strong, where the average diameter before the accelerated stability test was 12.02 mm and 11.58 mm after the accelerated stability test.

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27

Porozhnyuk, L. A., N. S. Lupandina e A. V. Nepomenko. "Cytogenetic assessment of the quality of media treated with Hermetia Illucens zoocompost components". BIO Web of Conferences 103 (2024): 00030. http://dx.doi.org/10.1051/bioconf/202410300030.

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The influence of black soldier fly maggots vermiculture zoocompost water extract components on the proliferative activity of root apexes’ meristem and the root system growth of Allium cepa L was studied. Allium-test was used as a biological analysis, approved by International Program on Chemical Safety (IPCS) for monitoring environmental contaminants, substances, and chemicals. The cytogenetic effects, resulting from the action of zoocompost’s water-soluble components and manifesting themselves in abnormalities of mitosis stages, were identified. The «dose-effect» relationship between the water extract components’ content and the mitotic activity of Allium cepa L meristem was determined. The influence of zoocompost water extract components on the elongation zone of root apexes, which affects root system growth, is demonstrated. It is revealed that the biogenic elements of zoocompost water extract components produce a stimulating effect at certain concentrations. The evaluated doses inhibit the proliferative activity of meristem and the growth of the root system. The inhibiting effect is probably due to the increased salts content in the water extract, which causes plasmolysis of cells’ cytoplasm, and alkalosis, caused by the presence of ammonia. It is recommended to take into account the dosage of biologically active substances in zoocompost during the formulation development of fertilizing mixes for plant cultivation.

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Lun, Thang Lam, Arihiro Iwasaki, Kiyotake Suenaga e Hisashi Kato-Noguchi. "Isolation and Identification of Plant-Growth Inhibitory Constituents from Polygonum chinense Linn and Evaluation of Their Bioherbicidal Potential". Plants 12, n. 7 (6 aprile 2023): 1577. http://dx.doi.org/10.3390/plants12071577.

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Abstract (sommario):

Polygonum chinense Linn. is a medicinal and invasive plant that belongs to the family Polygonaceae. The pharmacological activities and phytochemical constituents of Polygonum chinense are well reported, but the allelopathic effects and potent allelopathic substances of P. chinense remain to be investigated. Hence, this experiment was conducted to separate and characterize potentially allelopathic substances from an extract of the Polygonum chinense plant. The Polygonum chinense plant extracts highly suppressed the growth of cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), barnyard grass (Echinochloa crusgalli (L.) P. Beauv.), and timothy grass (Phleum pratense L.) seedlings in a species- and concentration-dependent way. Two active substances were separated using a series of purification procedures and determined through spectral analysis as (−)-3-hydroxy-β-ionone and (−)-3-hydroxy-7,8-dihydro-β-ionone. These two compounds significantly suppressed the seedling growth of Lepidium sativum (cress) at concentrations of 0.01 and 1 mM, respectively. The extract concentrations necessary for 50% growth inhibition (I50 values) of the cress hypocotyls and roots were 0.05 and 0.07 mM for (−)-3-hydroxy-β-ionone, respectively, and 0.42 and 1.29 mM for (−)-3-hydroxy-7,8-β-ionone, respectively. These findings suggest that these two compounds are in charge of the inhibitory effects of the Polygonum chinense extract and may serve as weed control agents.

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KYAW, Ei H., e Hisashi KATO-NOGUCHI. "Allelopathic potential of Acacia pennata (L.) Willd. leaf extracts against the seedling growth of six test plants". Notulae Botanicae Horti Agrobotanici Cluj-Napoca 48, n. 3 (23 settembre 2020): 1534–42. http://dx.doi.org/10.15835/nbha48312022.

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Abstract (sommario):

Acacia pennata (L.) Willd (Mimosaceae), a woody climbing plant, is used as a traditional medicinal plant in the South and Southeast Asia regions and has been documented to have various pharmacological effects. However, the allelopathy of this plant still remains unclear. Thus, the allelopathic potential of A. pennata leaf extracts was examined against the seedling growth of dicot plants [alfalfa (Medicago sativa L.), cress (Lepidium sativum L.), and lettuce (Lactuca sativa L.)] and monocot plants [barnyard grass (Echinochloa crus-galli (L.) Beauv.), Italian ryegrass (Lolium multiﬂorum Lam.), and timothy (Phleum pratense L.)] at six different concentrations. The results showed that the A. pennata leaf extracts inhibited the seedling growth of all the test plant species at concentrations ≥3 mg dry weight (D.W.) equivalent extract mL-1. The inhibitory activity of the extracts against both shoot and root growth varied with concentration and tested plants. The concentrations required for 50% inhibition of the test plant shoots and roots were 1.5-16.1 and 1.4-8.6 mg D.W. equivalent extract mL-1, respectively. The root growth of all the test plant species was more sensitive to the extracts than their shoot growth, except alfalfa. The results of the present study indicate that the A. pennata leaf extracts may have allelopathic potential and may contain allelopathic substances. Therefore, further studies are required for isolation and identification of the growth inhibitory substances which are responsible for the allelopathic effect of A. pennata.

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Khatun, Mst Rokeya, Shunya Tojo, Toshiaki Teruya e Hisashi Kato-Noguchi. "The Allelopathic Effects of Trewia nudiflora Leaf Extracts and Its Identified Substances". Plants 12, n. 6 (20 marzo 2023): 1375. http://dx.doi.org/10.3390/plants12061375.

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Abstract (sommario):

Trewia nudiflora Linn. is a woody plant of the Euphorbiaceae family. It is well known for its use as a folk remedy, but its potential for phytotoxicity has not been explored. Therefore, this study investigated the allelopathic potential and the allelopathic substances in T. nudiflora leaves. The aqueous methanol extract of T. nudiflora was found to have a toxic effect on the plants used in the experiment. The shoot and root development of lettuce (Lactuca sativa L.) and foxtail fescue (Vulpia myuros L.) were significantly (p ≤ 0.05) reduced by the T. nudiflora extracts. The growth inhibition by the T. nudiflora extracts was proportional to the extract concentration and varied with the test plant species. The chromatographic separation of the extracts resulted in the isolation of two substances, identified as loliolide and 6,7,8-trimethoxycoumarin based on their respective spectral analyses. Both substances significantly inhibited lettuce growth at a concentration of 0.01 mM. To inhibit 50% of the growth of the lettuce, the required concentration of loliolide was 0.043 to 0.128 mM, while that of 6,7,8-trimethoxycoumarin was 0.028 to 0.032 mM. Comparing these values, the lettuce growth was more sensitive to 6,7,8-trimethoxycoumarin than loliolide, suggesting that 6,7,8-trimethoxycoumarin was more effective than loliolide. Therefore, the inhibition of the growth of the lettuce and foxtail fescue suggests that loliolide and 6,7,8-trimethoxycoumarin are responsible for the phytotoxicity of the T. nudiflora leaf extracts. Thus, the growth-inhibitory effectiveness of the T. nudiflora extracts and the identified loliolide and 6,7,8-trimethoxycoumarin may be used to develop bioherbicides that restrict the growth of weeds.

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Pugacheva, Anna, Kristina Bikmetova e Yuliya Smirnova. "Sorbents of Phenols As a Components of the Nutritional Medium in Microclonal Reproduction of Plants". Natural Systems and Resources, n. 3 (ottobre 2021): 39–48. http://dx.doi.org/10.15688/nsr.jvolsu.2021.3.6.

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Abstract (sommario):

In the process of microclonal reproduction, plants secrete various substances into the nutrient medium, for example, phenolic compounds, which act as inhibitors of growth processes and, accordingly, prevent the normal development of explants in vitro. Plant tissues are treated with stabilizing substances, and various sorbents are also used as components of the nutrient medium to neutralize the negative effects of phenols. This paper presents an overview of the approved methods for solving the problem of sorption of phenolic compounds during microclonal propagation of plants. Various studies are considering the addition of certain components to the nutrient medium that prevent the release of harmful growth-inhibiting substances. Most often, various carbon compounds, such as activated carbon, are used as an adsorbent. The authors, based on the analysis of domestic and foreign literature on this topic, conclude that the most effective and frequently used are carbon compounds and the polymer polyvinyl pyrrolidone, less common is the use of the following inhibitory substances: ascorbic and citric acids, silver nitrate and mercury chloride. According to the results of the conducted analytical studies, the prospects of using such substances as thermally expanded graphite (TEG) and colloidal silicon dioxide as sorbents in the composition of the drug “Polysorb” were revealed. Due to the inhomogeneous porous structure, including both micropores and meso- or macropores, TEG is able to adsorb pollutants both from the solution and from the water surface, which makes it a potential sorbent for phenolic compounds. The effect of silicon dioxide, in amorphous form, on plants in vitro has already been successfully tested by some researchers, which indicates the prospects of its study.

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Hao, Jianjun J., Huawei Liu, Irwin Ronaldo Donis-Gonzalez, Xiao Hong Lu, A. Daniel Jones e Dennis W. Fulbright. "Antimicrobial Activity of Chestnut Extracts for Potential Use in Managing Soilborne Plant Pathogens". Plant Disease 96, n. 3 (marzo 2012): 354–60. http://dx.doi.org/10.1094/pdis-03-11-0169.

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Abstract (sommario):

Chestnut extracts were studied for antimicrobial activity against selected microorganisms, including plant pathogens. Chestnut extract on paper discs was applied to an agar medium to evaluate the inhibition to multiple microorganisms or the extract was added at various concentrations to a culture medium to evaluate the growth of target microorganisms. Chestnut type, tissue of plants (shell, pellicle, and leaf), extraction methods, and physical characteristics were studied to determine antimicrobial activity. Most test microorganisms were inhibited by the extracts at different effective concentrations for 50% growth inhibition (EC50). Pseudomonas fluorescens was the most sensitive (EC50 = 4.4 μg/μl), Phytophthora cambivora was one of the least inhibited (EC50 = 185 μg/μl), and Cryphonectria parasitica was not inhibited. Extracts of the Japanese × European chestnut (Castanea crenata × C. sativa) ‘Colossal’ showed a greater inhibition than those of wild trees of the Chinese species (C. mollissima). High temperature did not affect the inhibitory effect. Extracts from chestnut pellicle had the highest concentration of antimicrobial compound, compared with leaf and shell. The active fraction contained several substances with molecular masses consistent with one flavonol glycoside and several terpenoid substances. Pellicle and shell tissue reduced radish scab disease caused by Streptomyces scabies in the greenhouse.

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Wang, Haiyan, Rong Zhang, Yanan Duan, Weitao Jiang, Xuesen Chen, Xiang Shen, Chengmiao Yin e Zhiquan Mao. "The Endophytic Strain Trichoderma asperellum 6S-2: An Efficient Biocontrol Agent against Apple Replant Disease in China and a Potential Plant-Growth-Promoting Fungus". Journal of Fungi 7, n. 12 (8 dicembre 2021): 1050. http://dx.doi.org/10.3390/jof7121050.

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Abstract (sommario):

A study was conducted for endophytic antagonistic fungi obtained from the roots of healthy apple trees growing in nine replanted orchards in Shandong Province, China. The fungi were assessed for their ability to inhibit Fusarium proliferatum f. sp. malus domestica MR5, a fungal strain associated with apple replant disease (ARD). An effective endophyte, designated as strain 6S-2, was isolated and identified as Trichoderma asperellum. Strain 6S-2 demonstrated protease, amylase, cellulase, and laccase activities, which are important for the parasitic and antagonistic functions of pathogenic fungi. The inhibition rate of 6S-2 against Fusarium proliferatum f. sp. malus domestica MR5 was 52.41%. Strain 6S-2 also secreted iron carriers, auxin, ammonia and was able to solubilize phosphorus. Its fermentation extract and volatile substances inhibited the growth of MR5, causing its hyphae to twist, shrink, swell, and rupture. The antifungal activity of the 6S-2 fermentation extract increased with increasing concentrations. It promoted the production and elongation of Arabidopsis thaliana lateral roots, and the strongest effects were seen at a concentration of 50 mg/mL. A GC-MS analysis of the 6S-2 fermentation extract and volatile substances showed that they comprised mainly alkanes, alcohols, and furanones, as well as the specific volatile substance 6-PP. The application of 6S-2 spore suspension to replanted apple orchard soils reduced plant oxidative damage and promoted plant growth in a pot experiment. Therefore, the endophytic strain T. asperellum 6S-2 has the potential to serve as an effective biocontrol fungus for the prevention of ARD in China, and appears to promote plant growth.

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34

JITĂREANU, Alexandra, Gabriela TĂTĂRÎNGĂ, Ana-Maria ZBANCIOC e Ursula STĂNESCU. "Toxicity of Some Cinnamic Acid Derivatives to Common Bean (Phaseolus vulgaris)". Notulae Botanicae Horti Agrobotanici Cluj-Napoca 39, n. 2 (21 novembre 2011): 130. http://dx.doi.org/10.15835/nbha3927183.

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Abstract (sommario):

Cinnamic acid derivatives are an important class of biologically active compounds, playing an important role in the plantsâ€™ development, but may also present a wide range of actions: antimicrobial, antioxidant, antiinflamatory, antitumoral. The present study investigated the toxicity of ten cinnamic acid derivatives on Phaseolus vulgaris, this being the first step in evaluating their pharmacotoxicological potential (usually, plant toxicity tests are used for ecotoxicity assessment, but they can also provide some useful general information about the toxic potential of a pharmaceutical substance to living organisms). The bean seeds were exposed to three different concentrations of each substance (28.6 Î¼g/cm2, 57.3 Î¼g/cm2, 114.6 Î¼g/cm2). All the tests were conducted in Petri dishes, using an artificial substrate (Whatman filter paper) impregnated with the investigated compounds. The analyzed elements were seedling length, root length, percentage of seeds that developed into seedlings, fresh seedling weight and the total polyphenols content. The tested compounds showed phytotoxic effects, inhibiting the growth of the plants and the biosynthesis of polyphenols as compared to the control. The substances with high logP values showed greater phytotoxic potential, but to establish an exact correlation between hydrophobicity and toxicity of the molecules a QSAR analysis must be further done.

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35

Wai Thet Tin, Wai, Hisayoshi Hayashi, Toshihiko Otomatsu, Katsutoshi Hirose, Koji Hasegawa e Hideyuki Shigemori. "Structure-Activity Relationships of Natural Occurring Plant Growth-Inhibiting Substance Caprolactam and Its Related Compounds". HETEROCYCLES 78, n. 10 (2009): 2439. http://dx.doi.org/10.3987/com-09-11782.

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36

Hossen, Kawsar, Krishna Rany Das, Shun Okada, Arihiro Iwasaki, Kiyotake Suenaga e Hisashi Kato-Noguchi. "Allelopathic Potential and Active Substances from Wedelia Chinensis (Osbeck)". Foods 9, n. 11 (2 novembre 2020): 1591. http://dx.doi.org/10.3390/foods9111591.

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Abstract (sommario):

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 (I50 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.

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Huang, Xiaolong, Jingzhong Chen, Jiming Liu, Jia Li, Mengyao Wu e Bingli Tong. "Autotoxicity Hinders the Natural Regeneration of Cinnamomum migao H. W. Li in Southwest China". Forests 10, n. 10 (18 ottobre 2019): 919. http://dx.doi.org/10.3390/f10100919.

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Autotoxicity is a widespread phenomenon in nature and is considered to be the main factor affecting new natural recruitment of plant populations, which was proven in many natural populations. Cinnamomum migao H. W. Li is an endemic medicinal woody plant species mainly distributed in Southwestern China and is defined as an endangered species by the Red Paper of Endangered Plants in China. The lack of seedlings is considered a key reason for population degeneration; however, no studies were conducted to explain its causes. C. migao contains substances with high allelopathic potential, such as terpenoids, phenolics, and flavonoids, and has strong allelopathic effects on other species. Therefore, we speculate that one of the reasons for C. migao seedling scarcity in the wild is that it exhibits autotoxic allelopathy. In this study, which was performed from the perspective of autotoxicity, we collected leaves, pericarp, seeds, and branches of the same population; we simulated the effects of decomposition and release of litter from these different anatomical parts of C. migao in the field; and we conducted 210-day control experiments on seedling growth, with different concentration gradients, using associated aqueous extracts. The results showed that the leaf aqueous extract (leafAE) significantly inhibited growth indicators and increased damage of the lipid structure of the cell membrane of seedlings, suggesting that autotoxicity from C. migao is a factor restraining seedling growth. The results of the analyses of soil properties showed that, compared with the other treatments, leafAE treatment inhibited soil enzyme activity and also had an impact on soil fungi. Although leafAE could promote soil fertility to some extent, it did not change the effect of autotoxic substances on seedling growth. We conclude that autotoxicity is the main obstacle inhibiting seedling growth and the factor restraining the natural regeneration of C. migao.

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38

Silva, Rakiely M., Alice N. A. Peres, Lázaro E. P. Peres, Fábio L. Olivares, Sara Sangi, Natália A. Canellas, Riccardo Spaccini, Silvana Cangemi e Luciano P. Canellas. "Humic Substances Isolated from Recycled Biomass Trigger Jasmonic Acid Biosynthesis and Signalling". Plants 12, n. 17 (1 settembre 2023): 3148. http://dx.doi.org/10.3390/plants12173148.

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Intensive agriculture maintains high crop yields through chemical inputs, which are well known for their adverse effects on environmental quality and human health. Innovative technologies are required to reduce the risk generated by the extensive and harmful use of pesticides. The plant biostimulants made from humic substances isolated from recyclable biomass offer an alternative approach to address the need for replacing conventional agrochemicals without compromising the crop yield. The stimulatory effects of humic substances are commonly associated with plant hormones, particularly auxins. However, jasmonic acid (JA) is crucial metabolite in mediating the defence responses and governing plant growth and development. This work aimed to evaluate the changes in the biosynthesis and signalling pathway of JA in tomato seedlings treated with humic acids (HA) isolated from vermicompost. We use the tomato model system cultivar Micro-Tom (MT) harbouring a reporter gene fused to a synthetic promoter that responds to jasmonic acid (JERE::GUS). The transcript levels of genes involved in JA generation and activity were also determined using qRT-PCR. The application of HA promoted plant growth and altered the JA status, as revealed by both GUS and qRT-PCR assays. Both JA enzymatic synthesis (LOX, OPR3) and JA signalling genes (JAZ and JAR) were found in higher transcription levels in plants treated with HA. In addition, ethylene (ETR4) and auxin (ARF6) signalling components were positively modulated by HA, revealing a hormonal cross-talk. Our results prove that the plant defence system linked to JA can be emulated by HA application without growth inhibition.

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39

Boonmee, Sutjaritpan, Arihiro Iwasaki, Kiyotake Suenaga e Hisashi Kato-Noguchi. "Identification of 6,7-Dimethoxychromone as a Potent Allelochemical from Jatropha podagrica". Natural Product Communications 13, n. 11 (novembre 2018): 1934578X1801301. http://dx.doi.org/10.1177/1934578x1801301126.

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Jatropha podagrica Hook. is cultivated as an ornamental plant and is also used in traditional medicine. The species has various pharmacological properties, but it has not yet been investigated for any potential allelopathic activity and allelopathic substances. In this study, an allelopathic active substance was isolated from an aqueous methanol extract of J. podagrica leaves through chromatography and reverse-phase HPLC. The substance was characterized as 6,7-dimethoxychromone by spectral analysis. 6,7-Dimethoxychromone significantly inhibited the shoots and roots of cress at concentrations greater than 0.3 mM. The concentrations required of 6,7-dimethoxychromone for 50% growth inhibition of cress shoots and roots were 0.95 and 0.83 mM, respectively. The inhibitory activity against the seedling growth of cress indicates that 6,7-dimethoxychromone may contribute to the allelopathic effects and may be responsible for the allelopathic activity in J. podagrica. This report is the first on the allelopathic activity of 6,7-dimethoxychromone as an allelopathic substance from J. podagrica.

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40

Dewi Rosmalia, Minarni e Mhd Riza Marjoni. "Effect of Nutmeg (Myristica Fragrans) Methanolic Extract to the Growth of Dental Plaque Bacteria". DENTA 16, n. 2 (31 agosto 2022): 74–80. http://dx.doi.org/10.30649/denta.v16i2.3.

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Background: One of the causes of dental caries is Streptococcus mutant bacteria which has the ability to change the sugar content of food waste into lactic acid as the initial process of caries. One of the efforts to overcome dental caries is to use natural ingredients such as nutmeg. Every part of nutmeg has active substances that are efficacious as antimicrobial, antibacterial, antioxidant, antifungal and anti-inflammatory. Pulpam, seeds and fuli of nutmeg showed as potential extracts in inhibiting the growth of Streptococcus mutans. Objective: This study aimed to analyze methanol extracts from pericarpium, pulpam, fuli and nutmeg seeds against the growth of Streptococcus mutans bacteria that causes dental plaque. Methods: The research was conducted by diffusion method using BHI agar media and incubated anaerobically at 37°C for 24 hours. Results: The results of the calculation of the average diameter of the inhibition zones from the extract of fuli, seeds, pulpam and pericarpium of the nutmeg plant were 19.00 mm, 25.33 mm, 15.66 mm, 22.66 mm, and 21.83 mm, respectively. Data analysis using ANOVA (one way) showed that there were significant differences in all groups at p<0.05. The results of the LSD test showed that there were significant differences in all treatment groups. Conclusion: Methanol extract from fruit and fruit parts of nutmeg showed the ability to inhibit the growth of bacteria that cause dental plaque.

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41

Khatun, Mst Rokeya, Shunya Tojo, Toshiaki Teruya e Hisashi Kato-Noguchi. "Trewia nudiflora Linn, a Medicinal Plant: Allelopathic Potential and Characterization of Bioactive Compounds from Its Leaf Extracts". Horticulturae 9, n. 8 (7 agosto 2023): 897. http://dx.doi.org/10.3390/horticulturae9080897.

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Trewia nudiflora Linn. is a valuable forest resource due to its economic, ethnomedicinal, and ecological properties; however, its allelopathic potential is undocumented. Therefore, this research was designed to investigate the allelopathic impacts of T. nudiflora leaf extracts on alfalfa (Medicago sativa L.) and barnyard grass (Echinochloa crus-galli (L.) P. Beauv.) growth, as well as to isolate and to identify the active allelopathic substances responsible for these effects. A bioassay experiment with eight different treatments (0.1, 0.3, 1, 3, 10, 30, 100, and 300 mg dry weight (DW) equivalents of T. nudiflora extracts in mL−1) was carried out. The results showed that the growth of both plants decreased with increasing contents of T. nudiflora extracts, with the effect depending on the plant species and reaching its peak at a concentration of a 300 mg DW equivalent of T. nudiflora extract in mL−1. Active substances were isolated and identified using an HPLC system, which revealed the presences of methyl gallate and pinoresinol in aqueous methanol extracts of T. nudiflora. The shoot and root lengths of the alfalfa and the barnyard grass decreased significantly when they were treated with the methyl gallate and the pinoresinol. The allelopathic inhibition increased with increasing compound concentrations, with the root growth being more sensitive to the pinoresinol than to the methyl gallate, and it was significantly higher at the concentration of 10 mM. These results indicated that the T. nudiflora leaf extracts limited the growth of the treated plants, and the methyl gallate and pinoresinol in the extracts may have caused the inhibition of the T. nudiflora extracts. Thus, the leaf extracts of T. nudiflora and the substances methyl gallate and pinoresinol could be incorporated into sustainable agricultural practices or used to develop bioherbicides that would promote sustainable weed management practices.

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42

Aksoy, Emre, Amir Maqbool, Bayram Ali Yerlikaya e Fazli Wahid. "Bitki Peptit ve Amino Asit Taşıyıcılarının Demir Taşınmasındaki Görevleri". Turkish Journal of Agriculture - Food Science and Technology 10, sp1 (30 dicembre 2022): 2646–55. http://dx.doi.org/10.24925/turjaf.v10isp1.2646-2655.5600.

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Iron (Fe) is an important micronutrient for plants, and its deficiency causes serious yield losses by inhibiting plant growth and development. Detailed studies have been carried out for many years on the uptake of available iron in the soil by plants and its transport to plant organs. These studies proved that Fe can be transported in chelated form with some organic substances including peptides and amino acids. However, detailed studies have not been conducted on the uptake of peptide- or amino acid-chelated Fe into the plant or its transport between organs. Few studies have focused on the oligopeptide transporter (OPT) and drug/metabolite transporter (DMT) families. The possible roles of the recently discovered UMAMIT amino acid transporter family have not been studied in iron transport in plants yet. In this review, the transporter families responsible for the uptake and translocation of iron were summarized. Then, the roles of the OPT, DMT, and UMAMIT families in transporting iron-peptide and iron-amino acid complexes were discussed in detail.

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43

Goldner, W. R., F. M. Hoffman e R. J. Medve. "Allelopathic effects of Cladonia cristatella on ectomycorrhizal fungi common to bituminous strip-mine spoils". Canadian Journal of Botany 64, n. 8 (1 agosto 1986): 1586–90. http://dx.doi.org/10.1139/b86-212.

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Acetone–toluene extracts of Cladonia cristatella inhibited the growth of fungi known to form ectomycorrhizal associations with trees commonly found on bituminous strip-mine spoils in western Pennsylvania. Growth of Pisolithus tinctorius and Suillus luteus was completely inhibited by C. cristatella extracts over a 30-d bioassay period. Thelephora terrestris was dead after 17 d. The growth of Cenococcum graniforme was unaffected by lichen extracts. D-Usnic acid, a major secondary compound of the C. cristatella extract, was found to inhibit the growth of P. tinctorius. This inhibition, however, did not account for the total inhibition of P. tinctorius demonstrated by the gross acetone–toluene extract. Other secondary compounds, and potential allelopathic substances, present in the extract were barbatic acid, didymic acid, condidymic acid, subdidymic acid, fumarprotocetraric acid, squamatic acid, and rhodocladonic acid.

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44

Hossen, Kawsar, Krishna Rany Das, Yuka Asato, Toshiaki Teruya e Hisashi Kato-Noguchi. "Allelopathic Activity and Characterization of Allelopathic Substances from Elaeocarpus floribundus Blume Leaves for the Development of Bioherbicides". Agronomy 12, n. 1 (27 dicembre 2021): 57. http://dx.doi.org/10.3390/agronomy12010057.

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To help protect the environment as well as increase agricultural production, the use of synthetic herbicides must be reduced and replaced with plant-based bioherbicides. Elaeocarpus floribundus is a perennial, evergreen, and medium-sized plant grown in different areas of the world. The pharmaceutical properties and various uses of Elaeocarpus floribundus have been reported, but its allelopathic potential has not yet been explored. Thus, we carried out the present study to identify allelopathic compounds from Elaeocarpus floribundus. Aqueous MeOH extracts of Elaeocarpus floribundus significantly suppressed the growth of the tested species (cress and barnyard grass) in a dose- and species-dependent way. The three most active allelopathic substances were isolated via chromatographic steps and characterized as (3R)-3-hydroxy-β-ionone, cis-3-hydroxy-α-ionone, and loliolide. All three substances significantly limited the seedling growth of cress, and the compound (3R)-3-hydroxy-β-ionone had stronger allelopathic effects than cis-3-hydroxy-α-ionone and loliolide. The concentrations of the compounds required for 50% growth inhibition (I50 value) of the cress seedlings were in the range of 0.0001–0.0005 M. The findings of this study indicate that all three phytotoxic substances contribute to the phytotoxicity of Elaeocarpus floribundus.

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45

Pandey, H., V. Pandey, S. K. Nandi e L. M. S. Palni. "Role of plant growth substances in regulating pseudomonocotyly and correlative inhibition in some alpine Himalayan rosettes". South African Journal of Botany 125 (settembre 2019): 493–98. http://dx.doi.org/10.1016/j.sajb.2019.08.017.

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46

Frolova, Anna S., Anna D. Fokina, Irina S. Milentyeva, Lyudmila K. Asyakina, Larisa A. Proskuryakova e Alexander Y. Prosekov. "The Biological Active Substances of Taraxacum officinale and Arctium lappa from the Siberian Federal District". International Journal of Molecular Sciences 25, n. 6 (13 marzo 2024): 3263. http://dx.doi.org/10.3390/ijms25063263.

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Currently, scientists are increasingly focusing on utilizing the natural flora of the planet to search for and isolate individual bioactive substances that prevent various diseases, contribute to increased life expectancy, and affect all major life-supporting systems in the human body. This study describes the examination of the composition of plant raw materials from the Siberian Federal District. The research focuses on plant specimens from the root parts of Taraxacum officinale and Arctium lappa, collected in the Kemerovo region. The study determines the contents of the water-soluble vitamins B and C in the research subjects. The investigation includes assessing antioxidant properties, antimicrobial activity, and flavonoid content in extracts based on plant raw materials. All samples show a high percentage of antioxidant activity, with the highest antioxidant activity for T. officinale at 85.51 and that for A. lappa at 88.97. The results indicate low antimicrobial activity against Escherichia coli (growth inhibition zone up to 15.5 mm). Plant extracts contain significant amounts of B-group vitamins, with pyridoxine in T. officinale (156.40 μg/mL) and thiamine (46.20 μg/mL) and pyridoxine (357.10 μg/mL) in Arctium lappa. Flavonoids (rutin and quercetin) are identified in T. officinale and A. lappa extracts based on the study results.

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47

Kommerein, Nadine, Nina Vierengel, Jonathan Groß, Till Opatz, Bilal Al-Nawas e Lena Katharina Müller-Heupt. "Antiplanktonic and Antibiofilm Activity of Rheum palmatum against Streptococcus oralis and Porphyromonas gingivalis". Microorganisms 10, n. 5 (3 maggio 2022): 965. http://dx.doi.org/10.3390/microorganisms10050965.

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Periodontitis and peri-implantitis are inflammatory conditions with a high global prevalence. Oral pathogens such as Porphyromonas gingivalis play a crucial role in the development of dysbiotic biofilms associated with both diseases. The aim of our study was to identify plant-derived substances which mainly inhibit the growth of “disease promoting bacteria”, by comparing the effect of Rheum palmatum root extract against P. gingivalis and the commensal species Streptococcus oralis. Antiplanktonic activity was determined by measuring optical density and metabolic activity. Antibiofilm activity was quantified using metabolic activity assays and live/dead fluorescence staining combined with confocal laser scanning microscopy. At concentrations of 3.9 mg/L, R. palmatum root extract selectively inhibited planktonic growth of the oral pathogen P. gingivalis, while not inhibiting growth of S. oralis. Selective effects also occurred in mature biofilms, as P. gingivalis was significantly more stressed and inhibited than S. oralis. Our studies show that low concentrations of R. palmatum root extract specifically inhibit P. gingivalis growth, and offer a promising approach for the development of a potential topical agent to prevent alterations in the microbiome due to overgrowth of pathogenic P. gingivalis.

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48

Islam, A. K. M. Mominul, e Hisashi Kato-Noguchi. "Phytotoxic Activity ofOcimum tenuiflorumExtracts on Germination and Seedling Growth of Different Plant Species". Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/676242.

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Phytotoxic activity ofOcimum tenuiflorum(Lamiaceae) plant extracts was investigated against the germination and seedling growth of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), Italian ryegrass (Lolium multiflorum), barnyard grass (Echinochloa crus-galli), and timothy (Phleum pratense) at four different concentrations. The plant extracts at concentrations greater than 30 mg dry weight equivalent extract mL−1reduced significantly the total germination percent (GP), germination index (GI), germination energy (GE), speed of emergence (SE), seedling vigour index (SVI), and coefficient of the rate of germination (CRG) of all test species except barnyard grass and GP of lettuce. In contrast, time required for 50% germination (T50) and mean germination time (MGT) were increased at the same or higher than this concentration. The increasing trend ofT50and MGT and the decreasing trend of other indices indicated a significant inhibition or delay of germination of the test species byO. tenuiflorumplant extracts and vice versa. In addition, the shoot and root growth of all test species were significantly inhibited by the extracts at concentrations greater than 10 mg dry weight equivalent extract mL−1. TheI50values for shoot and root growth were ranged from 26 to 104 mg dry weight equivalent extract mL−1. Seedling growth was more sensitive to the extracts compared to seed germination. Results of this study suggest thatO. tenuiflorumplant extracts have phytotoxic properties and thus contain phytotoxic substances. Isolation and characterization of those substances from this plant may act as a tool for new natural, biodegradable herbicide development to control weeds.

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49

Krupiński, Grzegorz, e Piotr Sobiczyński. "The influence of plant extracts on growth of Erwinia amylovora - the causal agent of fire blight". Acta Agrobotanica 54, n. 2 (2013): 81–91. http://dx.doi.org/10.5586/aa.2001.025.

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Ethanol and water extracts obtained on Soxhlet apparatus from various organs and parts (leaves, flowers, shoots, onion, bark, fruit) of 30 herbal and woody plants species were tested for growth inhibition of Erwinia amylovora using agar diffusion method. Active extracts were found in 23 plant species but in 13 ofthem it was found for the first time. The highest diameter of growth inhibition zone of this bacterium was caused by extracts from Aloe arborescens, Juglans regia, Rhus typhina, Salvia offici nalis and Satureja hortensis. In almost all cases ethanol appeared to be a better solvent of active plant substances against E.amylovora than water.

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50

Moh, Seinn Moh, Arihiro Iwasaki, Kiyotake Suenaga e Hisashi Kato-Noguchi. "Allelopathic Activity of a Novel Compound, 5,6-Dihydrogen-11α-O-acetyl-12β-O-tigloyl-17β-marsdenin, and a Known Steroidal Glycoside from the Leaves of Marsdenia tenacissima (Roxb.) Moon". Agronomy 12, n. 7 (27 giugno 2022): 1536. http://dx.doi.org/10.3390/agronomy12071536.

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Abstract (sommario):

Medicinal plants are rich sources of bioactive substances that can be used to develop environmentally friendly weed control alternatives. Marsdenia tenacissima (Roxb.) Moon is a traditional medicinal plant well known for its pharmacological activities and several bioactive compounds. However, its allelopathy and related substances have not been reported. Hence, the present study was conducted to explore the allelopathic potential and substances from M. tenacissima leaves. Aqueous methanol extracts of M. tenacissima showed significant inhibitory activities against the growth of cress (Lepidium sativum L.) and Italian ryegrass (Lolium multiflorum Lam.). The extracts were purified through various chromatography steps, and two allelopathic substances were isolated and determined by spectral data to be steroidal glycoside 1 (5,6-dihydrogen-11α-O-acetyl-12β-O-tigloyl-17β-marsdenin), a novel compound, and steroidal glycoside 2 (5,6-dihydrogen-11α,12β-di-O-tigloyl-17β-marsdenin). Both compounds significantly inhibited the growth of cress seedlings. Steroidal glycoside 1 showed 1.6- and 4-times greater growth inhibitory potential against the cress shoots and roots than steroidal glycoside 2. The concentrations needed for 50% growth inhibition of the cress seedling shoots and roots were 0.46 and 0.03 mM for steroidal glycoside 1, respectively, and 0.74 and 0.12 mM for steroidal glycoside 2, respectively. Therefore, these results suggest that steroidal glycosides 1 and 2 may be responsible for the allelopathy of the M. tenacissima leaves.

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