scholarly journals Phytotoxic Activity of Clove Oil, Its Constituents, and Its Modification by Light Intensity in Broccoli and Common Lambsquarters (Chenopodium album)

Weed Science ◽  
2012 ◽  
Vol 60 (4) ◽  
pp. 607-611 ◽  
Author(s):  
Agnieszka Stokłosa ◽  
Renata Matraszek ◽  
Murray B. Isman ◽  
Mahesh K. Upadhyaya

Herbicidal activity of clove oil and its main constituents eugenol, β-caryophyllene, and α-humulene was studied by measuring their effects on cell membrane integrity in broccoli and common lambsquarters plants at the three- and nine-leaf stage, respectively. Roles of essential oil constituents in the overall phytotoxicity of clove oil, dose-response (10 to 160 mM) relationships of their phytotoxicity, and the effect of light intensity on phytotoxicity of clove oil and eugenol were studied. Most of the phytotoxicity of clove oil (2.5% solution) was due to eugenol, its largest constituent. β-caryophyllene and α-humulene played little or no role. Dose-response relationships showed that at equimolar concentration, eugenol was the most phytotoxic essential oil constituent of the clove oil. On a per unit biomass basis, membrane damage in response to clove oil and eugenol sprays decreased with increasing light intensity. This suggests that efficacy of essential oil in causing plant damage could be affected by light intensity experienced by plants prior to the oil spray.

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 833-837 ◽  
Author(s):  
Luke D. Bainard ◽  
Murray B. Isman ◽  
Mahesh K. Upadhyaya

Herbicidal activities of clove oil and its primary constituent eugenol on broccoli, common lambsquarters, and redroot pigweed and the role of crystalline leaf epicuticular wax (LEW) in susceptibility and retention of these essential oils were studied. Clove oil (2.5%) and eugenol (1.5%) were applied to leaves of greenhouse-grown broccoli, common lambsquarters, and redroot pigweed seedlings and effects on seedling growth and leaf cell membrane integrity were studied. Compared with eugenol, clove oil caused greater inhibition of seedling growth in all species. Both eugenol and clove oil caused greater loss of membrane integrity and inhibition of seedling growth in redroot pigweed, which has no crystalline LEW, compared with common lambsquarters, which has a thick layer of crystalline LEW. In broccoli seedlings with LEW, clove oil caused greater inhibition of growth than eugenol. Both clove oil and eugenol caused greater electrolyte leakage from broccoli leaves without LEW than in the leaves with LEW. Removal of LEW increased electrolyte leakage, an indicator of cell membrane damage, by 97% in eugenol-treated and 26% in clove oil–treated broccoli leaves. Susceptibility of broccoli seedlings and possibly some weed species may, therefore, be affected by factors (e.g., genetic, environmental) that influence the amount of LEW. Although the presence of LEW greatly reduced the retention of the essential oil solutions, there was no significant difference between the retention of clove oil and eugenol solutions, indicating that differences in their phytotoxicity to broccoli leaves was not due to differential foliar retention.


Weed Science ◽  
2008 ◽  
Vol 56 (5) ◽  
pp. 685-691 ◽  
Author(s):  
Andrew M. Westhoven ◽  
Greg R. Kruger ◽  
Corey K. Gerber ◽  
Jeff M. Stachler ◽  
Mark M. Loux ◽  
...  

Biotypes of common lambsquarters with tolerance to glyphosate have been identified in a number of states, but little is known about their fitness characteristics. Field and greenhouse studies were conducted to characterize the response of selected glyphosate-tolerant common lambsquarters biotypes to glyphosate, and also their biological and reproductive characteristics. In a greenhouse dose-response study, GR50and GR90values for four tolerant biotypes ranged from 1.48 to 3.22 and 8.73 to 18.7 kg ae ha−1, respectively, compared to 0.57 and 2.39 kg ae ha−1, respectively, for a glyphosate-sensitive biotype. In a field dose-response study, the GR50and GR90values were 0.06 and 0.48 kg ae ha−1, respectively, for a tolerant biotype, compared to 0.036 and 0.19 kg ae ha−1, respectively, for the sensitive biotype. The growth rate, time until flowering, and seed production of eight tolerant and two sensitive biotypes was evaluated in a field study. The tolerant biotypes grew taller, amassed more leaf area and dry weight, and advanced through growth stages more rapidly than sensitive biotypes during the early portion of the growing season. The tolerant biotypes were taller than sensitive biotypes at 6 and 10 wk after transplanting, but had lower dry weight at maturity. Tolerant biotypes initiated flower primordia approximately 6 to 8 wk after transplanting, whereas sensitive biotypes required 12 wk. However, no apparent fitness penalties were observed in glyphosate-tolerant biotypes based on seed-production estimates.


Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 147-151 ◽  
Author(s):  
Christopher L. Schuster ◽  
Douglas E. Shoup ◽  
Kassim Al-Khatib

Experiments were conducted to determine the efficacy of glyphosate on four common lambsquarters populations collected from Kansas, Nebraska, North Dakota, and Ohio. Glyphosate dose-response studies for common lambsquarters treated at 2.5-, 7.5-, and 15-cm heights showed that glyphosate at 1.1 kg ae ha−1caused more than 80% injury to 2.5-cm plants but less than 55% injury to 7.5- and 15-cm plants. All populations were susceptible to glyphosate at the 2.5-cm height. The glyphosate rate required to cause 50% injury (GR50) was 430, 500, 500, and 560 g ha−1for the Kansas, North Dakota, Ohio, and Nebraska populations, respectively. Differential response of common lambsquarters populations was evident with 15-cm plants where the GR50was glyphosate at 1,010, 1,230, 1,650, and 2,770 g ha−1for the Kansas, North Dakota, Nebraska, and Ohio populations, respectively. Reduced injury on 15-cm common lambsquarters plants by glyphosate may be partly attributed to reduced glyphosate accumulation per unit of plant tissues and enhanced calcium content in more-developed plants. All four common lambsquarters populations at the early seedling stage were susceptible to glyphosate, but tolerance increased as the plant developed and the extent of tolerance differed among populations.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Niluni M. Wijesundara ◽  
Song F. Lee ◽  
Zhenyu Cheng ◽  
Ross Davidson ◽  
H. P. Vasantha Rupasinghe

AbstractStreptococcus pyogenes is an important human pathogen worldwide. The identification of natural antibacterial phytochemicals has renewed interest due to the current scarcity of antibiotic development. Carvacrol is a monoterpenoid found in herbs. We evaluated carvacrol alone and combined with selected antibiotics against four strains of S. pyogenes in vitro. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of carvacrol against S. pyogenes were 125 µg/mL (0.53 mM) and 250 µg/mL (1.05 mM), respectively. Kill curve results showed that carvacrol exhibits instantaneous bactericidal activity against S. pyogenes. We also demonstrated the potential mechanism of action of carvacrol through compromising the cell membrane integrity. Carvacrol induced membrane integrity changes leading to leakage of cytoplasmic content such as lactate dehydrogenase enzymes and nucleic acids. We further confirmed dose-dependent rupturing of cells and cell deaths using transmission electron microscopy. The chequerboard assay results showed that carvacrol possesses an additive-synergistic effect with clindamycin or penicillin. Carvacrol alone, combined with clindamycin or penicillin, can be used as a safe and efficacious natural health product for managing streptococcal pharyngitis.


Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 88-91 ◽  
Author(s):  
D. E. Vanstone ◽  
E. H. Stobbe

Herbicidal activity of foliar-applied oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene] was light dependent in buckwheat (Fagopyrum esculentumMoench. ‘Tokyo’). Plants were not injured when placed in the dark for as long as 4 days after herbicide treatment. When these plants were brought to the light, injury occurred, albeit more slowly than when plants were placed in the light immediately after treatment. The rate of injury increased as light intensity increased. The most effective wave length was 565 to 615ηm, suggesting the involvement of a pigment with its absorption spectrum in this region. Chlorophyll content was not reduced by oxyfluorfen. Preliminary evidence suggests that photosynthesis was affected only after membrane integrity was disrupted.


Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 1029 ◽  
Author(s):  
Poul Martin Bendix ◽  
Adam Cohen Simonsen ◽  
Christoffer D. Florentsen ◽  
Swantje Christin Häger ◽  
Anna Mularski ◽  
...  

The plasma membrane surrounds every single cell and essentially shapes cell life by separating the interior from the external environment. Thus, maintenance of cell membrane integrity is essential to prevent death caused by disruption of the plasma membrane. To counteract plasma membrane injuries, eukaryotic cells have developed efficient repair tools that depend on Ca2+- and phospholipid-binding annexin proteins. Upon membrane damage, annexin family members are activated by a Ca2+ influx, enabling them to quickly bind at the damaged membrane and facilitate wound healing. Our recent studies, based on interdisciplinary research synergy across molecular cell biology, experimental membrane physics, and computational simulations show that annexins have additional biophysical functions in the repair response besides enabling membrane fusion. Annexins possess different membrane-shaping properties, allowing for a tailored response that involves rapid bending, constriction, and fusion of membrane edges for resealing. Moreover, some annexins have high affinity for highly curved membranes that appear at free edges near rupture sites, a property that might accelerate their recruitment for rapid repair. Here, we discuss the mechanisms of annexin-mediated membrane shaping and curvature sensing in the light of our interdisciplinary approach to study plasma membrane repair.


Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 399
Author(s):  
Ana C. Barros ◽  
Ana Pereira ◽  
Luis F. Melo ◽  
Juliana P. S. Sousa

Reverse osmosis (RO) depends on biocidal agents to control the operating costs associated to biofouling, although this implies the discharge of undesired chemicals into the aquatic environment. Therefore, a system providing pre-treated water free of biocides arises as an interesting solution to minimize the discharge of chemicals while enhancing RO filtration performance by inactivating bacteria that could form biofilms on the membrane system. This work proposes a pretreatment approach based on the immobilization of an industrially used antimicrobial agent (benzalkonium chloride—BAC) into millimetric aluminum oxide particles with prior surface activation with DA—dopamine. The antimicrobial efficacy of the functionalized particles was assessed against Escherichia coli planktonic cells through culturability and cell membrane integrity analysis. The results showed total inactivation of bacterial cells within five min for the highest particle concentration and 100% of cell membrane damage after 15 min for all concentrations. When reusing the same particles, a higher contact time was needed to reach the total inactivation, possibly due to partial blocking of immobilized biocide by dead bacteria adhering to the particles and to the residual leaching of biocide. The overall results support the use of Al2O3-DA-BAC particles as antimicrobial agents for sustainable biocidal applications in continuous water treatment systems.


Weed Science ◽  
2018 ◽  
Vol 66 (3) ◽  
pp. 404-414 ◽  
Author(s):  
Katarzyna Marcinkowska ◽  
Tadeusz Praczyk ◽  
Bartosz Łęgosz ◽  
Agnieszka Biedziak ◽  
Juliusz Pernak

AbstractFive bio-ionic liquids (BILs) with choline cations and fatty acid anions derived from pelargonic acid, glycerol tristearate, glycerol trioleate, canola oil, and coconut oil were synthesized and applied as spray adjuvants with three sulfonylurea herbicides: metsulfuron-methyl, iodosulfuron-methyl-sodium, and tribenuron-methyl. Physicochemical properties, including thermal stability, solubility, and surface activity, were determined, and the influence of these BILs on herbicidal efficacy was studied in greenhouse tests using four target weed species: common lambsquarters (Chenopodium album L.), cornflower (Centaurea cyanus L.), corn poppy (Papaver rhoeas L.), and oilseed rape (Brassica napus L.). BILs, particularly those with the oleic anion and anions derived from canola oil and coconut oil, greatly improved herbicidal activity. Addition of BILs to the spray solution significantly reduced the surface tension and contact angle of spray droplets and increased the area of herbicide deposit on the leaf surface.


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