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1
McKenzie, C. L., und B. Cartwright. „Susceptibility of Aphis gossypii (Glover) to Insecticides as Affected by Host Plant Using a Rapid Bioassay“. Journal of Entomological Science 29, Nr. 3 (01.07.1994): 289–301. http://dx.doi.org/10.18474/0749-8004-29.3.289.
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The susceptibility of Aphis gossypii (Glover) reared on watermelon or cotton to seven insecticides was determined using a Petri dish bioassay. Baseline susceptibility values to each insecticide for susceptible laboratory A. gossypii colonies varied between host plants, but aphids reared on cotton were generally more tolerant to insecticides than aphids from watermelon. The ratio of relative susceptibility of cotton aphids to melon aphids was as much as 1000 with dimethoate or 415 with bifenthrin, however, no significant differences in susceptibility was observed with chlorpyrifos between aphid populations from the two host plants. Orders of toxicity for the seven insecticides varied between host plant, but on watermelon, the order of toxicity was bifenthrin > oxydemeton-methyl > methomyl > dicrotophos > dimethoate > chlorpyrifos > endosulfan. Because of the wide range of response to insecticide doses observed with bifenthrin on melon aphid and with dimethoate and endosulfan against cotton aphid, use of the Petri dish bioassay method as a discriminating-dose field bioassay for these insecticides may not provide consistent estimations of the resistant nature of field populations. Bioassay data taken at 3 h were generally more consistent and provided a more predictive mortality model than those taken at 2 or 4 h for most insecticides. LC50 values estimated for dimethoate with melon aphids using leaf-spray or leaf residue bioassays differed little from LC50 values estimated with the Petri dish bioassay. Because Petri dish bioassays cost less than half as much as plant-based bioassays, provide comparable results, and require less assay time, this method is more suitable for use in monitoring for insecticide resistance in melon aphid.
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Araújo, Ademir Sérgio Ferreira, und Regina Teresa Rosim Monteiro. „Plant bioassays to assess toxicity of textile sludge compost“. Scientia Agricola 62, Nr. 3 (Juni 2005): 286–90. http://dx.doi.org/10.1590/s0103-90162005000300013.
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Composting of industrial wastes is increasing because of recycling requirements set on organic wastes. The evaluation of toxicity of these wastes by biological testing is therefore extremely important for screening the suitability of waste for land application. The toxicity of a textile sludge compost was investigated using seed germination and plant growth bioassays using soybean and wheat. Compost samples were mixed with water (seed germination bioassay) or nutrient solution (plant growth bioassay) at concentrations of 0, 19, 38, 76 and 152 g L-1. No negative effects were observed after five days of compost water-extract in relation to soybean and wheat seed germination. After fifteen days, under a hydroponics system, plant growth had harmful effects of the compost at concentrations above 38 g L-1. Textile sludge compost presented great phytotoxicity under hydroponics condition and the soybean and wheat were sensitive for evaluation of organic wastes in plant growth bioassays.
3
Kemppainen, R., H. Avikainen, M. Herranen, O. Reinikainen und R. Tahvonen. „PLANT BIOASSAY FOR SUBSTRATES“. Acta Horticulturae, Nr. 644 (Februar 2004): 211–15. http://dx.doi.org/10.17660/actahortic.2004.644.28.
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4
Ortega, Marta, José L. Alonso-Prados, Mercedes Villarroya und José M. García-Baudín. „Detection of Phytotoxic Soil Residues of Hexazinone and Simazine by a Biological Test Using Lepidium sativum L. var. Cresson“. Weed Technology 18, Nr. 3 (September 2004): 505–8. http://dx.doi.org/10.1614/wt-03-055.
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Current plant bioassays included in the guidelines for testing pesticides do not include the measurement of reproduction endpoints. A bioassay, based on reduction of flowering of cress was developed to detect soil residues of hexazinone and simazine at levels of 0.02 and 0.10 ppm, respectively. The endpoint used in the described bioassay is the percentage of plant viability that implies that the tested plants have reached the flowering stage. It was found that sensitivity of cress is lower in soils containing higher organic matter.
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Khalil, Yaseen, Kadambot H. M. Siddique, Phil Ward, Colin Piggin, Sze How Bong, Shabarinath Nambiar, Robert Trengove und Ken Flower. „A bioassay for prosulfocarb, pyroxasulfone and trifluralin detection and quantification in soil and crop residues“. Crop and Pasture Science 69, Nr. 6 (2018): 606. http://dx.doi.org/10.1071/cp18026.
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Three experiments were conducted to develop a bioassay method for assessing the bioavailability of prosulfocarb, pyroxasulfone and trifluralin in both crop residue and soil. In preliminary experiments, Italian ryegrass (Lolium multiflorum Lam.), cucumber (Cucumis sativus L.) and beetroot (Beta vulgaris L.) were tested as bioassay plant species for the three pre-emergent herbicides. Four growth parameters (shoot length, root length, fresh weight and dry weight) were measured for all plant species. Shoot-length inhibition was identified as the most responsive to the herbicide application rates. Italian ryegrass was the most sensitive species to all tested herbicides, whereas beetroot and cucumber had lower and similar sensitivity to shoot inhibition for the three herbicides. The bioassay species performed similarly in wheat and canola residues collected a few days after harvest. In bioassay calibration experiments, dose–response curves were developed for prosulfocarb, pyroxasulfone and trifluralin in a sandy loam soil typical of the grain belt of Western Australia and with wheat residue. The developed bioassay uses ryegrass shoot inhibition for relatively low suspected concentrations of herbicide, and cucumber shoot inhibition for higher rates. The bioassay was validated by spraying the three herbicides separately onto wheat residue and soil and comparing the concentrations derived from chemical analysis with those from the bioassay. All of the linear correlations between concentrations derived from chemical analyses and the bioassays were highly significant. These results indicate that the bioassay calibration curves are suitable for estimating herbicide concentrations in crop residue collected soon after harvest and a sandy-loam soil, low in organic matter.
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Heap, I. M. „Identification and documentation of herbicide resistance“. Comptes rendus 75, Nr. 4 (12.04.2005): 85–90. http://dx.doi.org/10.7202/706075ar.
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Proactive herbicide resistance management programs rely upon early detection of resistant populations and knowledge of which combinations of weed and herbicide are prone to the development of resistance. Annual weeds that are prolific seed producers, genetically diverse, and repeatedly exposed to a single herbicide mode of action, are prone to rapid development of resistance. When resistance is suspected, seed samples are collected and evaluated using a whole plant bioassay. Whole plant bioassays are conducted underfield, growth room, or Petri dish conditions. Complete dose response curves for the suspected resistant and a reference susceptible population are used to verify resistance. Bioassay, conducted in growth rooms, is the most reliable method for identification of new cases of herbicide resistance. Bioassays, based on the biochemical detection of a single mechanism of resistance, are not reliable for screening for new occurrences of resistance.
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Matthiessen, J. N., und M. A. Shackleton. „Advantageous attributes of larval whitefringed weevil, Naupactus leucoloma (Coleoptera: Curculionidae) for bioassaying soil fumigants, and responses to pure and plant-derived isothiocyanates“. Bulletin of Entomological Research 90, Nr. 4 (August 2000): 349–55. http://dx.doi.org/10.1017/s000748530000047x.
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AbstractFirst instars of the soil-inhabiting whitefringed weevil, Naupactus leucoloma(Boheman), are a particularly good bioassay model for assessing volatile soil fumigants and biofumigants. Eggs are readily obtained and can be stored for long periods with larvae hatched on demand and the first instar is non-feeding, surviving without food or shelter. Longevity varies with temperature, but readily accommodates the period required to conduct bioassays without appreciable mortality of untreated controls. In vitro bioassays of pure methyl isothiocyanate, the active ingredient from metham sodium soil fumigant, and the less volatile 2-phenylethyl isothiocyanate, sensitively detected differences in toxicity and effects of temperature. Bioassay of volatiles emitted from hydrolysed tissue of various isothiocyanate-producing Brassicaplants revealed widely varying toxicity effects, indicating that bioassays with N. leucoloma are a sensitive and relevant indicator of the potential of different plants for biofumigation of soil-borne pest organisms.
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Han, D. Y., D. L. Coplin, W. D. Bauer und H. A. J. Hoitink. „A Rapid Bioassay for Screening Rhizosphere Microorganisms for Their Ability to Induce Systemic Resistance“. Phytopathology® 90, Nr. 4 (April 2000): 327–32. http://dx.doi.org/10.1094/phyto.2000.90.4.327.
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We developed a rapid and miniaturized bioassay for screening large numbers of rhizosphere microorganisms for their ability to induce systemic resistance to bacterial leaf spot of radish caused by Xanthomonas campestris pv. armoraciae. In this bioassay, Pantoea agglomerans strain E278Ar controlled symptoms of disease as effectively as 2,6-dichloroisonicotinic acid when applied to the roots of seedlings produced in growth pouches in a soilless system. E278Ar essentially did not migrate from seedling roots to the foliage. This suggests that induction of systemic resistance could best explain the observed reduction in disease severity. Three mini-Tn5Km-induced mutants of strain E278Ar were isolated that had lost the ability to induce resistance. The bioassay also was used to demonstrate that the fungal biocontrol agent Trichoderma hamatum strain 382 induces systemic resistance in radish. The bioassay required only 14 to 18 days from seeding until rating for disease severity, which is 10 to 14 days less than earlier bioassays.
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Aalders, L. T., R. Minchin, R. A. Hill, M. Braithwaite, N. L. Bell und A. Stewart. „Development of a tomato/root knot nematode bioassay to screen beneficial microbes“. New Zealand Plant Protection 62 (01.08.2009): 28–33. http://dx.doi.org/10.30843/nzpp.2009.62.4802.
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In common with other root knot nematodes Meloidogyne hapla is a serious plant pest A rapid screening system for candidate microbes that benefit plant growth is a first step to developing screening bioassays in other plantnematode systems Cultures of M hapla established on tomatoes were used to define the nematode damage function and required bioassay duration for this plantpest system followed by scaleup to a glasshouse level The quantities of Meloidogyne inoculum were chosen such that they would cause minor moderate or severe plant damage; hence the degree of protection afforded by the microbes in bioassays could be readily evaluated An inoculation rate of 3542 eggs/plant caused a significant reduction in shoot weight (30) and an increase in root galling in excess of 50 Percentage of root gall and root gall index were good indicators of nematode impact and provide a relatively quick method of assessment
10
Elden, T. C. „Laboratory Screening Techniques for Evaluation of Soybean Germplasm for Resistance to Twospotted Spider Mite (Acari: Tetranychidae)“. Journal of Entomological Science 34, Nr. 1 (01.01.1999): 132–43. http://dx.doi.org/10.18474/0749-8004-34.1.132.
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Thirty-one soybean, Glycine max (L.) Merrill, accessions from maturity groups II through VIII were evaluated in excised and intact (whole plant) leaf bioassays to determine the ability of these bioassays to detect differences in susceptibility to the twospotted spider mite, Tetranychus urticae Koch. Although there were few significant differences between bioassays for variables measured within maturity groupings, the excised leaf bioassay which was easier to set up and monitor and took three-fourths less growth chamber space also had less variation among replications and repeated tests and detected a greater number of differences among accessions. Although there were significant differences among soybean accessions within a maturity group for specific variables, results suggest that high levels of resistance to the twospotted spider mite are not present in the germplasm screened. Several accessions screened, with known resistance to foliar feeding insects, were significantly less preferred for spider mite oviposition and development. However, it was apparent that the gene(s) controlling insect resistance do not impart the same level of resistance to the twospotted spider mite. Results of this study, based on differences in susceptibility among soybean accessions, demonstrate that the excised leaf bioassay should prove to be an efficient and uniform laboratory bioassay to screen soybean germplasm for resistance to the twospotted spider mite.
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Brooks, F. E. „Detached-Leaf Bioassay for Evaluating Taro Resistance to Phytophthora colocasiae“. Plant Disease 92, Nr. 1 (Januar 2008): 126–31. http://dx.doi.org/10.1094/pdis-92-1-0126.
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Taro leaf blight disease, caused by Phytophthora colocasiae, is a major limiting factor in taro production worldwide. P. colocasiae is an aerial pathogen similar to P. infestans, causal agent of potato late blight disease, but occurs in warmer climates. In the year-round subsistence cropping systems of the Pacific Islands, resistant cultivars are essential. Breeding lines from Southeast Asia and Oceania were tested in American Samoa for resistance to taro leaf blight using a detached-leaf bioassay and field trials. Mean lesion diameters from bioassays were highly correlated with field estimates of the number of healthy leaves per plant and yield (corm weight). However, the bioassay did not adequately assess infection efficiency. Additional experiments revealed that attached leaves had smaller lesion diameters than detached leaves incubated in closed containers, but both were very highly correlated. Taro resistance increased with plant age and the second-oldest leaf was more resistant than the third-oldest leaf. The bioassay was a fast, space-saving, effective method of screening taro lines for post-penetration resistance to P. colocasiae. It also provided an easily standardized method of evaluating host–pathogen interactions under controlled conditions.
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Ranft, R. D., S. S. Seefeldt, M. Zhang und D. L. Barnes. „Development of a Soil Bioassay for Triclopyr Residues and Comparison with a Laboratory Extraction“. Weed Technology 24, Nr. 4 (Dezember 2010): 538–43. http://dx.doi.org/10.1614/wt-d-09-00055.1.
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The use of triclopyr for the removal of woody and broad-leaf vegetation in right-of-ways and agricultural settings has been proposed for Alaska. Triclopyr concentrations in soil after application are of concern because residual herbicide may affect growth of subsequent vegetation. In order to measure triclopyr residues in soil and determine the amount of herbicide taken up by the plant, soil bioassays were developed. Four agricultural species, turnip, lettuce, mustard, and radish, were tested to determine sensitivity to triclopyr in a 1-wk bioassay. The sensitivity (I50) of turnip, lettuce, mustard, and radish was 0.33 ± 0.05 kg ai ha−1, 0.78 ± 0.11 kg ai ha−1, 0.78 ± 0.07 kg ai ha−1, and 0.85 ± 0.10 kg ai ha−1 (mean ± SE), respectively. Mustard was the most consistent crop in the bioassay with a midrange response to triclopyr and lowest standard deviation for germination as compared to the other species. Thus, it was used in a bioassay to determine triclopyr concentrations in a field trial. The bioassay of mustard closely matched residual amounts of triclopyr in a field trial determined by chemical extraction. Estimates of residual triclopyr concentrations using the bioassay method were sometimes less than the triclopyr concentration determined using a chemical extraction. These differences in concentrations were most evident after spring thaw when the chemical extraction determined there was enough triclopyr in the soil to reduce mustard growth over 60%, yet the bioassay measured only a 10% reduction. The chemical extraction method may have identified nonphototoxic metabolites of triclopyr to be the herbicidal triclopyr acid. These methods, when analyzed together with a dose–response curve, offer a more complete picture of triclopyr residues and the potential for carryover injury to other plant species.
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Scheck, Heather J., Marilyn L. Canfield, Jay W. Pscheidt und Larry W. Moore. „Rapid Evaluation of Pathogenicity in Pseudomonas syringae pv. syringae with a Lilac Tissue Culture Bioassay and Syringomycin DNA Probes“. Plant Disease 81, Nr. 8 (August 1997): 905–10. http://dx.doi.org/10.1094/pdis.1997.81.8.905.
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Losses from diseases caused by Pseudomonas syringae pv. syringae occur on a large number of deciduous woody plants in commercial nurseries in the Pacific Northwest. Bioassays for pathogenicity are one step in the identification of P. syringae pv. syringae and are usually performed on the host of isolation; however, woody plants can take months to develop symptoms. A bioassay with highly susceptible lilac (Syringa vulgaris ‘Sensation’) tissue culture plantlets evaluated pathogenicity in strains of P. syringae pv. syringae isolated from 25 species of deciduous woody plants. DNA colony hybridization with the syrB probe for a syringomycin synthetase gene and the syrD probe for a syringomycin export gene was also evaluated as a method for identifying pathogens. Of 552 strains provisionally identified as P. syringae pv. syringae, 59% were pathogenic in the bioassay and hybridized with the syr probes, while 19% were non-pathogenic and did not hybridize with the syr probes, giving 78% agreement between the two methods. Nine percent of strains were pathogenic in the bioassay but did not hybridize with the syr probes, and 13% were not pathogenic in the bioassay but did hybridize with the syr probes. These methods detected pathogenic strains of P. syringae pv. syringae isolated from diverse woody plants in 5 to 16 days.
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KANZAKI, Hiroshi, Toshihiko KAGEMORI, Satomi ASANO und Kazuyoshi KAWAZU. „Improved Bioassay Method for Plant Transformation Inhibitors“. Bioscience, Biotechnology, and Biochemistry 62, Nr. 12 (Januar 1998): 2328–33. http://dx.doi.org/10.1271/bbb.62.2328.
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Castle, S. J., N. Prabhaker, T. J. Henneberry und N. C. Toscano. „Host plant influence on susceptibility of Bemisia tabaci (Hemiptera: Aleyrodidae) to insecticides“. Bulletin of Entomological Research 99, Nr. 3 (24.10.2008): 263–73. http://dx.doi.org/10.1017/s0007485308006329.
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AbstractA resistance monitoring program conducted for the polyphagous whitefly, Bemisia tabaci (Gennadius), in Imperial Valley, CA, USA generated a large set of LC50s for adults collected from broccoli, cantaloupe and cotton crops over a four-year period. A vial bioassay and, subsequently, a yellow-sticky card bioassay produced similar temporal profiles of relative susceptibilities to the pyrethroid insecticide bifenthrin. Both bioassays revealed that whiteflies collected from broccoli were significantly less susceptible to bifenthrin compared to the other two crops. A similar finding was observed for endosulfan and the mixture of bifenthrin+endosulfan in the yellow-sticky card bioassay. The possibility that seasonal differences contributed to the observed differences in susceptibility provided the impetus to conduct a reciprocal transfer experiment using broccoli (or kale) and cantaloupe grown simultaneously in the field and greenhouse. Whitefly adults collected from an organic farm over three consecutive weeks had significantly higher LC50s on kale than those collected the same day on cantaloupe. After culturing in the greenhouse on broccoli or cantaloupe and testing again, LC50s remained significantly higher on broccoli after one week and again at the F1 generation. In contrast, whiteflies originating on kale in the field and transferred to cantaloupes in the greenhouse had significantly reduced LC50s at the F1 generation. When tested against the bifenthrin+endosulfan mixture, significantly higher LC50s were generated for whiteflies reared on broccoli in the greenhouse at one week and the F1 compared to the field source from cantaloupes. The consistently higher LC50s for whiteflies on broccoli and other Brassica spp. crops, compared to cantaloupes or cotton, point to statistically significant host-plant influences that are expressed in both field-collected and greenhouse-reared populations of whiteflies.
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Gatch, Emily W., und Lindsey J. du Toit. „A Soil Bioassay for Predicting the Risk of Spinach Fusarium wilt“. Plant Disease 99, Nr. 4 (April 2015): 512–26. http://dx.doi.org/10.1094/pdis-08-14-0804-re.
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The maritime Pacific Northwest is the only region of the United States suitable for production of spinach seed, a cool-season, daylength-sensitive crop. However, the acidic soils of this region are highly conducive to spinach Fusarium wilt, caused by Fusarium oxysporum f. sp. spinaciae. Rotations of at least 10 to 15 years between spinach seed crops are necessary to reduce the high risk of losses to this disease. The objectives of this study were to develop a greenhouse soil bioassay to assess the relative risk of Fusarium wilt in fields intended for spinach seed production, and to identify soil chemical and physical properties associated with conduciveness to this disease. Preliminary bioassays established a protocol for growing spinach plants in a greenhouse environment and inducing Fusarium wilt symptoms so that the bioassay can be completed in <2 months. Test soils with a range of Fusarium wilt inoculum potentials, and three spinach inbred parent lines (highly susceptible, moderately susceptible, and moderately resistant to Fusarium wilt) were used to evaluate sensitivity of the bioassay to different levels of risk of Fusarium wilt. Then, from 2010 to 2013, spinach seed growers and stakeholders submitted soil samples from 147 fields for evaluation with the bioassay. The fields were each under consideration for planting a spinach seed crop, yet the bioassay revealed a wide range in Fusarium wilt inoculum potential among soil samples. Differences in susceptibility to Fusarium wilt of the three inbred lines were key to detecting differences in wilt risk among soils. Visits to spinach seed crops planted in fields evaluated in the bioassay, as well as test plots of the three inbred lines planted in growers’ seed crops, confirmed the predictive value of the bioassay for Fusarium wilt risk. Correlation analyses for 23 soil properties revealed significant relationships of 15 soil properties with the Fusarium wilt potential of a soil, but the correlations were influenced significantly by susceptibility of the inbred line to Fusarium wilt (13, 10, and 8 soil properties correlated significantly with Fusarium wilt risk for the susceptible, moderate, and partially resistant inbreds, respectively). Multiple regression analyses identified different statistical models for prediction of Fusarium wilt risk depending on the spinach inbred line, but the best fitting model explained <34% of the variability in Fusarium wilt risk among 121 fields evaluated in the soil bioassay. Thus, no model was robust enough to replace the bioassay for the purpose of predicting Fusarium wilt risk.
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Hatzinikolaou, Ageliki S., Ilias G. Eleftherohorinos und Ioannis B. Vasilakoglou. „Influence of Formulation on the Activity and Persistence of Pendimethalin“. Weed Technology 18, Nr. 2 (Juni 2004): 397–403. http://dx.doi.org/10.1614/wt-03-121r1.
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The activity of emulsifiable concentrate (EC) formulation of pendimethalin was studied using a petri dish bioassay based on root response of corn, oat, sorghum, and sugar beet grown in soil. Furthermore, the oat bioassay was used to determine the activity of EC, microencapsulated (ME), and water-dispersible granule (WDG) formulations of pendimethalin. Also, field persistence in soil of these pendimethalin formulations was studied with petri dish and pot bioassays, based on root response of oat and sugar beet. All bioassays indicated that activity of all pendimethalin formulations was increased with increasing herbicide concentration. In silty clay loam soil, oat and sugar beet exhibited the highest sensitivity to EC-pendimethalin concentrations and corn the lowest; sorghum showed intermediate herbicide sensitivity. EC of pendimethalin showed the highest activity on oat and ME pendimethalin the lowest; WDG-pendimethalin showed similar activity to that of ME pendimethalin. Field persistence was significantly increased with increasing rate of application, but it was slightly increased by the ME formulation.
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Tardif, François J., und Gilles D. Leroux. „Rhizome Bud Viability of Quackgrass (Elytrigia repens) Treated with Glyphosate and Quizalofop“. Weed Technology 4, Nr. 3 (September 1990): 529–33. http://dx.doi.org/10.1017/s0890037x00025914.
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The effect of the isopropylamine salt of glyphosate and the ethyl ester of quizalofop on the rhizome bud viability of five quackgrass biotypes was tested. Two bioassays used were: direct measure of the growth of the bud on an agar medium and determination of the respiratory activity with tetrazolium chloride. The response to herbicide treatments differed among biotypes. The growth bioassay showed lower viability than the tetrazolium bioassay. Quizalofop reduced viability more than glyphosate. Viability of untreated buds increased with increasing distance from the base of the rhizome. The viability of herbicide-treated buds was more or less equal regardless of the position. It appeared that both herbicides were translocated to all the rhizome buds.
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Selim, Salah A., Steven W. O'Neal, Merrill A. Ross und Carole A. Lembi. „Bioassay of Photosynthetic Inhibitors in Water and Aqueous Soil Extracts with Eurasian Watermilfoil (Myriophyllum spicatum)“. Weed Science 37, Nr. 6 (November 1989): 810–14. http://dx.doi.org/10.1017/s004317450007288x.
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Eurasian watermilfoil, an aquatic flowering plant, was found to be a suitable bioassay plant for the detection of photosynthetic inhibitor herbicides in water and aqueous extracts of soil. Stock cultures of Eurasian watermilfoil were maintained in an algal-free medium under constant environmental conditions. Oxygen evolution from three lateral shoots 3 to 5 cm in length was measured before and after herbicide treatment. Inhibition of photosynthesis was detected within 10 min of treatment. Concentrations as low as 5.9 × 10–8M terbacil and 6.4 × 10–8M diuron were detected in water. Simazine, atrazine, and metribuzin were detected in water at a concentration of 10–7M. Eurasian watermilfoil bioassays in lake water spiked with various concentrations of terbacil, metribuzin, atrazine, and simazine indicated that the bioresidual activity of these chemicals can be estimated in samples of natural water without extraction or purification. Using aqueous extracts taken from herbicide-treated soil, the Eurasian watermilfoil bioassay detected minimum levels of 0.047 and 0.07 kg/ha terbacil and atrazine, respectively. Neither soybean nor oat showed visible injury symptoms at these concentrations. The Eurasian watermilfoil bioassay has the advantage of being more rapid and/or more sensitive than methods using algae, oat seedlings, or leaf discs.
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Shilaluke, Kolwane Calphonia, und Annah Ntsamaeeng Moteetee. „Insecticidal Activities and GC-MS Analysis of the Selected Family Members of Meliaceae Used Traditionally as Insecticides“. Plants 11, Nr. 22 (10.11.2022): 3046. http://dx.doi.org/10.3390/plants11223046.
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The environmental and health risks associated with synthetic pesticides have increased the demand for botanical insecticides as safer and biodegradable alternatives to control insect pests in agriculture. Hence in this study, five Meliaceae species were evaluated for their insecticidal activities against the Spodoptera frugiperda and the Plutella xylostella larvae, as well as their chemical constituents. Repellence, feeding deterrence, and topical application bioassays were employed to evaluate their insecticidal activities. GC-MS analysis was performed to identify chemical compounds present in each plant. The repellence bioassay indicated that Melia azedarach extracts exhibited the highest repellence percentage against S. frugiperda (95%) and P. xylostella (90%). The feeding deterrence bioassay showed that M. azedarach and Trichilia dregeana extracts displayed excellent antifeeding activity against the S. frugiperda (deterrent coefficient, 83.95) and P. xylostella (deterrent coefficient, 112.25), respectively. The topical application bioassay demonstrated that Ekebergia capensis extracts had the highest larval mortality against S. frugiperda (LD50 0.14 mg/kg). Conversely, M. azedarach extracts showed the highest larval mortality against P. xylostella (LD50 0.14 mg/kg). GC-MS analysis revealed that all plant extracts had compounds belonging to the two noteworthy groups (phenols and terpenes), which possess insecticidal properties. Overall, this study lends scientific credence to the folkloric use of Meliaceae species as potential biocontrol agents against insect pests.
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Santos, J. R. A., und D. I. Leskovar. „Interference from Broccoli Residue on Brassica Germination and Seedling Growth“. Journal of the American Society for Horticultural Science 122, Nr. 5 (September 1997): 715–20. http://dx.doi.org/10.21273/jashs.122.5.715.
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Germination bioassays were conducted to assess if water-soluble extracts of broccoli (Brassica oleracea L. var. italica L.) affect germination of broccoli, cabbage (Brassica oleracea L. var. capitata L.), and cauliflower (Brassica oleracea L. var. botrytis L.). Greenhouse experiments also examined the phytotoxic potential of soil previously cropped with broccoli and broccoli plant parts on seedling growth of those species. The first bioassay used nonsterile extracts (NSEs) and filter-sterilized extracts (FSEs) of broccoli leaves. The second bioassay used nonsterile and filter-sterilized leaf extracts (LEs), stem and root extracts (SREs), and whole broccoli plant (leaves, stems, and roots) extracts (WPEs). Broccoli and cabbage germination were not affected by NSEs or FSEs, but the latter reduced cauliflower germination by 22%. LEs and SREs decreased germination speed for broccoli, cabbage and cauliflower. Greenhouse seedlings were grown in soil previously cropped with broccoli or fallow soil at three fertilizer levels. Broccoli soil was phytotoxic to cauliflower but enhanced broccoli and cabbage seedling growth. The differential sensitivity to broccoli plant residue was in the order of cauliflower > broccoli = cabbage, with SR residue having the highest phytotoxic potential.
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Fitriyah, Fauziatul, Muhammad Abdul Aziz, Sri Wahyuni, Hana Fadila, Insyiah Meida Luktyansyah, Sulastri Sulastri, Priyono Priyono und Siswanto Siswanto. „Biostimulant Activity of <i>Sargassum</i> sp. Extracts on Early Growth of <i>Zea mays</i> L. and the Phytohormones Content Analysis“. Journal of Tropical Biodiversity and Biotechnology 7, Nr. 2 (20.06.2022): 69178. http://dx.doi.org/10.22146/jtbb.69178.
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Seaweed has been gaining global interest in agriculture for the development of marine-based plant biostimulants. This research aimed to study the effect of three different liquid extracts of Sargassum sp., acidic, alkaline, and water extract, on the germination and early growth of maize and to evaluate the phytohormones content responsible for the growth. Phytohormones content including Indole-3-acetic acid (IAA), gibberellins (GA), kinetin and zeatin were analyzed using high-performance liquid chromatography (HPLC) and bioassay was performed twice on maize. Parameters observed on the bioassay were germination percentage, number of roots, shoot length, shoot weight and root weight under 4 different concentrations with 0.5; 1.5; 3.5; and 5% in the first bioassay and 3.5% concentration in the second bioassay. Both bioassays following randomized complete design and the data were analyzed using one-way ANOVA using post hoc test of Duncan Multiple Range Test (DMRT) at error probability of 5% in Genestat software. Phytohormones content in the seaweed extract indicated that alkaline extract was rich in IAA, gibberellin, and zeatin content, while water extract showed the highest kinetin content. The first bioassay indicated that lower concentration of the seaweed extracts gave better growth in all extracts, therefore a 3.5% concentration was chosen for the second bioassay with higher replication for each treatment. The second bioassay confirmed alkaline extract resulted in the highest germination while the highest seedling height, number of roots, shoot and root weight were resulted from acidic extract treatment. In conclusion, Sargassum sp. extracts obtained from acidic, alkaline, and water-based extraction methods, were able to improve the shoot and root growth of maize plants. The acidic extract showed the highest growth promotion among other extracts with the lowest phytohormones content.
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Galdino, Tarcísio Visintin da Silva, Marcelo Coutinho Picanço, Elisangela Gomes Fidelis de Morais, Nilson Rodrigues Silva, Geverson Aelton Rezende da Silva und Mayara Cristina Lopes. „Bioassay method for toxicity studies of insecticide formulations to Tuta absoluta (meyrick, 1917)“. Ciência e Agrotecnologia 35, Nr. 5 (Oktober 2011): 869–77. http://dx.doi.org/10.1590/s1413-70542011000500002.
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Chemical control is the main method for controlling the tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae). Reported techniques for the evaluation of insecticide toxicity to the tomato leafminer are not in agreement with field conditions and do not allow us to verify whether doses used in the field are efficient for control. Thus, the objective of this work was to develop a bioassay methodology to study the toxicity of insecticide formulations to T. absoluta that represent field conditions for fast-acting insecticides (neurotoxics and inhibitors of respiration) and slow-acting insecticides (Bacillus thuringiensis and insect growth regulators). The leaf-dip method was the most efficient method for toxicity studies of insecticides formulations to T. absoluta. We verified that bioassays with fast-acting insecticides should be performed with glass Petri dishes containing one tomato foliole from the 4th leaf from the plant apex infested with 10 larvae of 3rd instar and these bioassays can last 48 hours. Conversely, bioassays with slow-acting insecticides should be performed with two-liter transparent PET bottles containing the 4th leaf from the plant apex, with their petioles immersed in a glass bottle containing 120 mL of water, and this leaf should be infested with 10 larvae of 2nd instar and this bioassays can last seven days.
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FYLES, J. W., I. H. FYLES und M. C. FELLER. „COMPARISON OF NITROGEN MINERALIZATION IN FOREST FLOOR MATERIALS USING AEROBIC AND ANAEROBIC INCUBATION AND BIOASSAY TECHNIQUES“. Canadian Journal of Soil Science 70, Nr. 1 (01.02.1990): 73–81. http://dx.doi.org/10.4141/cjss90-008.
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Nitrogen mineralization in five forest floors of differing morphological characteristics was compared using a greenhouse plant bioassay and laboratory aerobic and anaerobic incubations. Forest floors dominated by F materials mineralized more N and had higher k values than those dominated by H. Plant N uptake in the bioassay was highly correlated with N mineralized during the laboratory incubations across all forest floors but was 50–80% lower than predictions based on first-order kinetic parameters derived from the aerobic incubation. The relationship between bioassay plant uptake and predicted N mineralization differed among forest floors, indicating that the effect of plants on dynamics of the mineralizable N pool differs among organic matter types. Differences in N mineralization characteristics between forest floor materials suggest that forest floor morphology may provide a basis for assessing site quality. Key words: Nitrogen, anaerobic mineralization, aerobic mineralization, bioassay, forest floor
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Moradi, Faramarz, Hossein Arouiee und Seyyed Neamati. „Bioassay of Flavonoids Crataegus oxyacantha with Plant Bionanosensor“. Egyptian Academic Journal of Biological Sciences, E. Medical Entomology & Parasitology 10, Nr. 2 (01.06.2018): 71–77. http://dx.doi.org/10.21608/eajbse.2018.26511.
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Germida, J. J., R. E. Karamanos und J. W. B. Stewart. „A Simple Microbial Bioassay for Plant Available Manganese“. Soil Science Society of America Journal 49, Nr. 6 (November 1985): 1411–15. http://dx.doi.org/10.2136/sssaj1985.03615995004900060016x.
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Feiler, Ute, Ilona Kirchesch und Peter Heininger. „A new plant-based bioassay for aquatic sediments“. Journal of Soils and Sediments 4, Nr. 4 (Dezember 2004): 261–66. http://dx.doi.org/10.1007/bf02991122.
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Castro, C. E., N. O. Belser, H. E. McKinney und I. J. Thomason. „Quantitative bioassay for chemotaxis with plant parasitic nematodes“. Journal of Chemical Ecology 15, Nr. 4 (April 1989): 1297–309. http://dx.doi.org/10.1007/bf01014831.
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Alim, Md Abdul, Janghoon Song, Un Taek Lim, Jang Jeon Choi und Md Alamgir Hossain. „Bioassay of Plant Extracts AgainstAleurodicus dispersus(Hemiptera: Aleyrodidae)“. Florida Entomologist 100, Nr. 2 (Juni 2017): 350–57. http://dx.doi.org/10.1653/024.100.0234.
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Chanway, C. P., und L. M. Nelson. „Tissue culture bioassay for plant growth promoting rhizobacteria“. Soil Biology and Biochemistry 23, Nr. 4 (Januar 1991): 331–33. http://dx.doi.org/10.1016/0038-0717(91)90187-o.
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Soriano, Gabriele, Claudia Petrillo, Marco Masi, Mabrouka Bouafiane, Aminata Khelil, Angela Tuzi, Rachele Isticato, Mónica Fernández-Aparicio und Alessio Cimmino. „Specialized Metabolites from the Allelopathic Plant Retama raetam as Potential Biopesticides“. Toxins 14, Nr. 5 (28.04.2022): 311. http://dx.doi.org/10.3390/toxins14050311.
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To cope with the rising food demand, modern agriculture practices are based on the indiscriminate use of agrochemicals. Although this strategy leads to a temporary solution, it also severely damages the environment, representing a risk to human health. A sustainable alternative to agrochemicals is the use of plant metabolites and plant-based pesticides, known to have minimal environmental impact compared to synthetic pesticides. Retama raetam is a shrub growing in Algeria’s desert areas, where it is commonly used in traditional medicine because of its antiseptic and antipyretic properties. Furthermore, its allelopathic features can be exploited to effectively control phytopathogens in the agricultural field. In this study, six compounds belonging to isoflavones and flavones subgroups have been isolated from the R. raetam dichloromethane extract and identified using spectroscopic and optical methods as alpinumisoflavone, hydroxyalpinumisoflavone, laburnetin, licoflavone C, retamasin B, and ephedroidin. Their antifungal activity was evaluated against the fungal phytopathogen Stemphylium vesicarium using a growth inhibition bioassay on PDA plates. Interestingly, the flavonoid laburnetin, the most active metabolite, displayed an inhibitory activity comparable to that exerted by the synthetic fungicide pentachloronitrobenzene, in a ten-fold lower concentration. The allelopathic activity of R. raetam metabolites against parasitic weeds was also investigated using two independent parasitic weed bioassays to discover potential activities on either suicidal stimulation or radicle growth inhibition of broomrapes. In this latter bioassay, ephedroidin strongly inhibited the growth of Orobanche cumana radicles and, therefore, can be proposed as a natural herbicide.
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Markell, S. G., und L. J. Francl. „Fusarium Head Blight Inoculum: Species Prevalence and Gibberella zeae Spore Type“. Plant Disease 87, Nr. 7 (Juli 2003): 814–20. http://dx.doi.org/10.1094/pdis.2003.87.7.814.
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The objectives of this study were to examine the relative abundance of Gibberella zeae ascospores and conidia and other Fusarium species on wheat spikes in a field environment, to relate inoculum counts of G. zeae to airborne spore counts, and to evaluate an inoculum bioassay technique. The inoculum levels of Fusarium species and airborne spores of G. zeae were measured in North Dakota during the 1999, 2000, and 2001 growing seasons. Spores were collected from wheat spikes in a 24-h potted-plant bioassay in a fallowed field and in a spring wheat plot bioassay. Inoculum levels of Fusarium species were assessed by placing a solution recovered from bioassays on selective medium; meanwhile, ascospores and conidia of G. zeae were enumerated microscopically. A Burkard cyclonic sampler measured airborne spore levels in the fallowed field. Wheat spikes were inoculated with known concentrations of conidia or ascospores, and rinsate was put on selective medium at different intervals to compare recovery rates. Known concentrations of both spore types were also applied directly to selective medium to compare with recovery of spore types from inoculated spikes. Fusarium graminearum was the most prevalent Fusarium species on wheat spikes, although F. moniliforme and F. poae counts were highest on some days. Approximately twice as many ascospores were recovered in both the 24-h potted-plant field bioassay and the cyclonic sampler as were conidia. Significantly more colonies were recovered from wheat spikes after conidial inoculation than after ascospore inoculation at an identical concentration regardless of time of rinsate collection. Colony numbers did not differ significantly following application of ascospores and conidia to selective medium. Results confirm the predominance of G. zeae inoculum in North America but indicate conidia play an important role in the primary disease cycle.
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SONG, JA-EUN, JEONG-MOON KIM, NA-HYUN LEE, JI-YEON YANG und HOI-SEON LEE. „Acaricidal and Insecticidal Activities of Essential Oils against a Stored-Food Mite and Stored-Grain Insects“. Journal of Food Protection 79, Nr. 1 (01.01.2016): 174–78. http://dx.doi.org/10.4315/0362-028x.jfp-15-109.
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ABSTRACT Twenty plant-derived oils were evaluated for their acaricidal and insecticidal activities against Sitotroga cerealella, Sitophilus oryzae, Sitophilus zeamais, and Tyrophagus putrescentiae adults, by using the fumigant and filter paper diffusion methods. Responses varied with bioassay systems, insect or mite species, plant oils, and exposure time. Based on the 50% lethal dose (LD50) values against S. oryzae and S. zeamais in the fumigant bioassay, Anethum graveolens oil (4.12 and 1.12 μg/cm3, respectively) induced the highest mortality, followed by Achillea millefolium (21.92 and 14.91 μg/cm3) and Eucalyptus dives (28.02 and 24.02 μg/cm3) oils, respectively. The most toxic oil based on the 50% lethal concentration values against T. putrescentiae was E. dives (3.13 μg/cm3), followed by Melaleuca leucadendron (3.93 μg/cm3) and Leptospermum pertersonii (4.41 μg/cm3). Neroli birgard oil (1.70 μg/cm3) was the most toxic based on the LD50 values against S. cerealella, followed by Citrus aurantium (1.80 μg/cm3) and Artemisia vulgaris (1.81 μg/cm3). The insecticidal and acaricidal activities of the plant oils in the filter paper diffusion bioassay were similar to those in the fumigant bioassay. In comparison, A. millefolium, A. graveolens, and E. dives oils were more effective against S. oryzae and S. zeamais in the fumigant bioassay than in the contact bioassay. These results indicate that the insecticidal activity of the three plant oils against S. oryzae and S. zeamais may be due to their fumigant action. Acaricidal activities of the A. millefolium, A. graveolens, and E. dives oils against T. putrescentiae were 2.62, 1.11, and 122 times higher than that of benzyl benzoate in the contact bioassay. These results indicate that A. millefolium, A. graveolens, and E. dives oils have potential for development as agents to control stored-grain insects and mites.
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Harrison, Howard F., Amnon Levi und C. S. Kousik. „A Survey of Watermelon Germplasm for Inhibitory Seed Exudates“. HortScience 43, Nr. 1 (Februar 2008): 138–42. http://dx.doi.org/10.21273/hortsci.43.1.138.
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Watermelon [Citrullus lanatus v. lanatus (Thunb.) Matsum & Nakai] seed exudates are inhibitory to germination and seedling growth of other plant species. A miniature bioassay experiment that measured proso millet (Panicum miliaceum L.) radicle growth was used to assess the inhibition caused by seed exudates of 125 genotypes of watermelon and related Citrullus species. Exudates of most genotypes were not inhibitory; however, exudates of 53 accessions reduced radicle growth in comparison with the control. In subsequent proso millet radicle growth experiments, genotypes were found to vary in inhibitory potential, and concentration response curves generated using filtered, pasteurized exudates were different among genotypes. Filter-sterilized seed exudates of Citrullus accessions also varied in the level of inhibition in a bioassay that measured their effect on sporangia formation by the watermelon pathogen, Phytophthora capsici. These observations suggest that constituents in Citrullus seed exudates affect organisms in the spermosphere and that the inhibitory potential of seed exudates varies among genotypes. Differences in concentration response curves in the millet bioassay and differences in the relative inhibition of genotypes in the millet and fungus bioassays indicate that the inhibitory constituents in seed exudates vary among genotypes.
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Ranjith, Sellappan, Thangavel Kalaiselvi, Muruganagounder Muthusami und Uthandi Sivakumar. „Maize Apoplastic Fluid Bacteria Alter Feeding Characteristics of Herbivore (Spodoptera frugiperda) in Maize“. Microorganisms 10, Nr. 9 (16.09.2022): 1850. http://dx.doi.org/10.3390/microorganisms10091850.
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Maize is an important cereal crop which is severely affected by Spodoptera frugiperda. The study aims to identify endophytic bacteria of maize root and leaf apoplastic fluid with bioprotective traits against S. frugiperda and plant growth promoting properties. Among 15 bacterial endophytic isolates, two strains—namely, RAF5 and LAF5—were selected and identified as Alcaligenes sp. MZ895490 and Bacillus amyloliquefaciens MZ895491, respectively. The bioprotective potential of B. amyloliquefaciens was evaluated through bioassays. In a no-choice bioassay, second instar larvae of S. frugiperda fed on B. amyloliquefaciens treated leaves (B+) recorded comparatively lesser growth (1.10 ± 0.19 mg mg−1 day−1) and consumptive (7.16 ± 3.48 mg mg−1 day−1) rates. In larval dip and choice bioassay, the same trend was observed. In detached leaf experiment, leaf feeding deterrence of S. frugiperda was found to be greater due to inoculation with B. amyloliquefaciens than Alcaligenes sp. The phenolics content of B. amyloliquefaciens inoculated plant was also found to be greater (3.06 ± 0.09 mg gallic acid g−1). However, plant biomass production was more in Alcaligenes sp inoculated treatment. The study thus demonstrates the potential utility of Alcaligenes sp. and B. amyloliquefaciens for improving growth and biotic (S. frugiperda) stress tolerance in maize.
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Sridhar, Vaddi, Avverahally Thammanna Sadashiva, Vala Keshava Rao, Padavala Swathi und Hanamant Shivalingappa Gadad. „Trichome and biochemical basis of resistance against Tuta absoluta in tomato genotypes“. Plant Genetic Resources: Characterization and Utilization 17, Nr. 03 (04.02.2019): 301–5. http://dx.doi.org/10.1017/s147926211800062x.
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AbstractSouth American tomato moth, Tuta absoluta, a serious pest of tomato (Solanum lycopersicum) in tropics and subtropics, is rapidly spreading world over. Twenty one wild/cultivated/advanced breeding lines of tomato were screened for resistance to T. absoluta under greenhouse conditions (choice bioassay) and promising genotypes were evaluated further for their antibiosis activity through no choice bioassay under in-vitro conditions. From 21 genotypes screened, six wild accessions viz., S. pennellii (LA 1940); S. chilense (LA 1963); S. arcanum (LA 2157); S. lycopersicum (LA1257) and S. corneliomulleri (LA 1292, LA1274) were relatively resistant to T. absoluta based on mean percent damage and were further studied under in-vitro conditions. These genotypes recorded relatively more larval mortality, prolonged larval and pupal duration with reduced adult emergence of T. absoluta. Among these six genotypes, S. pennellii (LA-1940) showed resistance both under choice and no choice bioassays with higher number of type IV trichomes, highest total flavonoids and phenols. In general, glandular trichomes (GTs) (type I, IV, VII) showed negative correlation in different genotypes of tomato with reference to larval number/plant, percent damage and adult activity, whereas type V (non-GTs) showed negative correlation with number of larvae/plant.
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van de Vossenberg, B. T. L. H., M. P. E. van Gent-Pelzer, M. Boerma, L. P. van der Gouw, T. A. J. van der Lee und J. H. Vossen. „An Alternative Bioassay for Synchytrium endobioticum Demonstrates the Expression of Potato Wart Resistance in Aboveground Plant Parts“. Phytopathology® 109, Nr. 6 (Juni 2019): 1043–52. http://dx.doi.org/10.1094/phyto-01-19-0024-r.
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The obligate biotrophic chytrid species Synchytrium endobioticum is the causal agent of potato wart disease. Currently, 39 pathotypes have been described based on their interaction with a differential set of potato varieties. Wart resistance and pathotyping is performed using bioassays in which etiolated tuber sprouts are inoculated. Here, we describe an alternative method in which aboveground plant parts are inoculated. Susceptible plants produced typical wart symptoms in developing but not in fully expanded aboveground organs. Colonization of the host by S. endobioticum was verified by screening for resting spores by microscopy and by molecular techniques using TaqMan polymerase chain reaction and RNAseq analysis. When applied to resistant plants, none of these symptoms were detectable. Recognition of S. endobioticum pathotypes by differentially resistant potato varieties was identical in axillary buds and the tuber-based bioassays. This suggests that S. endobioticum resistance genes are expressed in both etiolated “belowground” sprouts and green aboveground organs. RNAseq analysis demonstrated that the symptomatic aboveground materials contain less contaminants compared with resting spores extracted from tuber-based assays. This reduced microbial contamination in the aboveground bioassay could be an important advantage to study this obligate biotrophic plant–pathogen interaction. Because wart resistance is active in both below- and aboveground organs, the aboveground bioassay can potentially speed up screening for S. endobioticum resistance in potato breeding programs because it omits the requirement for tuber formation. In addition, possibilities arise to express S. endobioticum effectors in potato leaves through agroinfiltration, thereby providing additional phenotyping tools for research and breeding. [Formula: see text] Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .
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Jackson, D. Michael, und Janice R. Bohac. „ADULT AND LARVAL BIOASSAYS FOR DETERMINING RESISTANCE OF SWEETPOTATO GENOTYPES TO Diabrotica SPP.“ HortScience 40, Nr. 3 (Juni 2005): 869a—869. http://dx.doi.org/10.21273/hortsci.40.3.869a.
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Production of sweetpotatoes is severely limited by several insect pests, and new pest management approaches for this crop are needed. A host plant resistance research program typically depends on reliable bioassay procedures to streamline evaluation of germplasm. Thus, bioassay procedures were developed for both adults and larvae of two cucumber beetle species (Diabrotica balteata and D. undecimpunctata). For the adult bioassay, a piece of sweetpotato peel (periderm & cortex with stele removed) was embedded periderm-side up in plaster in a Petri dish, and a single adult was placed on it. Plugs were changed as needed and adult longevity was measured. A laboratory bioassay also was developed for Diabrotica larvae. Plugs (0.9 cm diameter) of sweetpotato peel or stele were placed periderm-side up into sterile microcentrifuge tubes (1.5 mL) containing 0.5 mL water-agar to prevent desiccation. One second instar Diabrotica was added to each micro centrifuge tube, which was held at 25 °C for 12 days. Surviving larvae were weighed. Diabrotica larvae grew larger when they were fed stele than when they were fed peels of any sweetpotato genotype. Larval growth was not different among genotypes for any of the stele treatments. However, larval growth on the peel of the resistant genotypes (Regal and W-375) was significantly lower than for the susceptible cultivars Beauregard or SC1149-19. These bioassays were consistent with field results, indicating that these techniques could be useful for evaluating pest resistance in sweetpotato genotypes for Diabrotica and other insect species.
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Conn, Kenneth L., George Lazarovits und Jerzy Nowak. „A gnotobiotic bioassay for studying interactions between potatoes and plant growth-promoting rhizobacteria“. Canadian Journal of Microbiology 43, Nr. 9 (01.09.1997): 801–8. http://dx.doi.org/10.1139/m97-117.
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A gnotobiotic bioassay, using potato plantlets derived from single-node explants and grown in test tubes containing potato nodal cutting medium (PNCM), was found to be highly useful for investigations of direct growth promotion by a nonfluorescent Pseudomonas sp. strain PsJN. Strain PsJN was used to optimize and evaluate this bioassay for purposes of screening other rhizosphere bacteria and identification of Tn5 mutants of strain PsJN deficient in growth-promoting properties. The selection of potato cultivar used in this bioassay was critical, as growth promotion of potatoes by strain PsJN was cultivar specific. Inoculated plantlets of cultivars Norchip, Kennebec, Shepody, and Chaleur showed, in root dry weight, a five- to eight-fold increase, two- to three-fold increase, no response, and a decrease of 50%, respectively. Haulm dry weight followed similar trends but was not as consistent an indicator of growth promotion. Bioassay results were not altered to any extent by minor changes in PNCM composition or by slight changes in temperature and light conditions. A rapid method for preparation of bacterial suspensions and inoculation of explants was developed. Inoculation of three explants taken from 6-week-old stock plantlets of cv. Kennebec for each Tn5 transconjugate of strain PsJN (total of 1500 transconjugates) enabled the elimination of 93% of those isolates that retained growth-promoting activity. The remaining 7% of isolates were retested and seven were confirmed to have lost growth-promoting ability. Bacteria from different genera were also screened with this bioassay. None of these bacteria increased the growth of potato plantlets, but several inhibited root and haulm growth.Key words: plant growth-promoting rhizobacteria, gnotobiotic, tissue culture, nonfluorescent pseudomonad, bacterium, potato.
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Williams, R. N., M. A. Ellis und D. S. Fickle. „Field and Bioassay Evaluations, 1988“. Insecticide and Acaricide Tests 14, Nr. 1 (01.01.1989): 70. http://dx.doi.org/10.1093/iat/14.1.70.
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Abstract Four insecticides were evaluated for efficacy against the adult Japanese beetle, tarnished plant bug, meadow spittlebug, and strawberry sap beetle. A 10-yr-old experimental raspberry planting at Wooster, Ohio, was used for this study. Replicates consisted of 18-ft2 areas, with 4 replicates/treatment in a randomized complete block design. Treatments were applied as foliar sprays at a rate of 100 gal/acre (935 liter/ha) on 5 Jul and 26 Jul, using a hand-held CO2 sprayer operating at 45 psi (3.2 kg/cm2) and equipped with a 9505-E-TeeJet nozzle. For the field evaluation readings of the number of live Japanese beetles in each plot were taken immediately before insecticides were applied; at 4 h after treatment; and at 2, 3, and 6 DAT. The bioassay evaluation began 26 Jul, after the insecticides had dried on foliage. Five leaves were sampled from each replicate and placed in 1-gal round ice cream containers. In the bioassay, 10 adult tarnished plant bugs, 10 meadow spittlebugs, and 10 strawberrry sap beetles were added to each container. The number of dead insects was recorded 24 h after exposure to the treated foliage. At 3 DAT a Japanese beetle bioassay of treated foliage was begun and the number of dead insects was recorded 24 h after exposure.
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Kanzaki, Hiroshi, Hiroto Toyoshima, Akio Kobayashi und Kazuyoshi Kawazu. „A Novel Bioassay Method for Inhibitors of Plant Transformation“. Bioscience, Biotechnology, and Biochemistry 58, Nr. 3 (Januar 1994): 531–34. http://dx.doi.org/10.1271/bbb.58.531.
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Cleve, K. Van, O. W. Heal und D. Roberts. „Bioassay of forest floor nitrogen supply for plant growth“. Canadian Journal of Forest Research 16, Nr. 6 (01.12.1986): 1320–26. http://dx.doi.org/10.1139/x86-233.
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Using a bioassay approach, this paper considers the nitrogen-supplying power of forest floors from examples of the major forest types in interior Alaska. Yield and net N uptake by paper birch seedlings grown in standardized mixtures of quartz sand and forest floor organic matter, and separate incubation estimates of N mineralization and nitrification for the forest floors, were employed to evaluate potential N supply. Black spruce and floodplain white spruce forest floors supplied only one-fifth the amount of N taken up by seedlings growing in other forest floors. Incubation estimates showed these forest floors yielded 4 and 15 times less extractable N, respectively, than the more fertile birch forest floors. In comparison with earlier estimates of P supply from these same forest floors, the upland types showed greater deficiency of N whereas floodplain types showed greater deficiency of P in control of seedling yield. The latter condition is attributed to the highly calcareous nature of the floodplain mineral soil, the consequent potential for P fixation, and hence greater potential deficiency of the element compared with N in mineralizing forest floors. Nitrogen concentration of the forest floors was the best predictor of bioassay response.
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Huang, Xiao-Lan, Yona Chen und Moshe Shenker. „Rapid whole-plant bioassay for phosphorus phytoavailability in soils“. Plant and Soil 271, Nr. 1-2 (April 2005): 365–76. http://dx.doi.org/10.1007/s11104-004-3551-7.
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Wall, Monroe E., Mansukh C. Wani, Thomas J. Hughes und Harold Taylor. „Plant Antimutagenic Agents, 1. General Bioassay and Isolation Procedures“. Journal of Natural Products 51, Nr. 5 (September 1988): 866–73. http://dx.doi.org/10.1021/np50059a009.
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Cleve, K. Van, und F. Harrison. „Bioassay of forest floor phosphorus supply for plant growth“. Canadian Journal of Forest Research 15, Nr. 1 (01.02.1985): 156–62. http://dx.doi.org/10.1139/x85-025.
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This paper considers the extent to which phosphorus (P) supply for plant use is controlled by the chemical quality of forest floor organic matter, independent of climate. Using plant bioassays, forest floor materials from representative examples of each of the major forest types in interior Alaska were examined for nutrient supplying power. The work supports conclusions reached in earlier studies which indicated that black spruce forest floors were highly nutrient limited compared with those of other interior Alaska forest types. In addition, floodplain white spruce forests may experience marked P deficiency because of dilution of the element by periodic siltation. Potential phosphorus supply for seedling growth was best described by P concentration of the rooting medium. The supply also was related to the concentrations of lignin and tannin which control forest floor decomposition and recycling of P within the microbial population.
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Cleve, K. Van, und A. F. Harrison. „Bioassay of forest floor phosphorus supply for plant growth“. Canadian Journal of Forest Research 15, Nr. 5 (01.10.1985): 1011. http://dx.doi.org/10.1139/x85-163.
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Gray, Morgan A., Kevin A. Nguyen, Wei Hao, Rodger J. Belisle, Helga Förster und James E. Adaskaveg. „Mobility of Oxathiapiprolin and Mefenoxam in Citrus Seedlings After Root Application and Implications for Managing Phytophthora Root Rot“. Plant Disease 104, Nr. 12 (Dezember 2020): 3159–65. http://dx.doi.org/10.1094/pdis-02-20-0391-re.
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Oxathiapiprolin is highly effective in the management of Phytophthora root rot of citrus; however, its uptake into plants after soil application is not known. This was investigated and compared with mefenoxam using potted citrus seedlings sampled 7, 10, 13, and 16 days after soil treatments. Bioassays and high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS) were used to quantify fungicide amounts in plant extracts. Distinct inhibition zones of mycelial growth of Phytophthora citrophthora were observed in bioassays when root, stem, or leaf extracts were added to filter paper disks on agar plates. Based on the two quantification methods, concentrations of both fungicides in the three tissue types and at all sampling times were above the mean effective concentration that provides 50% growth reduction values of the baseline sensitivities. Relative concentrations at the four sampling times sometimes varied between the two methods but, for both methods, concentrations of oxathiapiprolin were significantly higher in roots and leaves as compared with stems 10 days after treatment and statistically similar in the three tissues after 7 days. For mefenoxam, concentrations significantly increased in roots between 7 and 16 days after treatment and were significantly the highest in roots as compared with stems or leaves 16 days after treatment. Regressions of oxathiapiprolin and mefenoxam concentrations using HPLC-MS/MS on those calculated from bioassay standard curves indicated that the bioassays overestimated fungicide amounts in the extracts. The bioassay, however, can be considered an alternative option comparable with costly residue analyses in fungicide mobility studies in plants. Uptake of oxathiapiprolin at sufficient but low concentrations into plant roots provides an explanation for its long-lasting high activity in the management of Phytophthora root rot.
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Cubillos-Hinojosa, Juan Guillermo, Pablo Ernesto Milian Mindiola, Jorge Luis Hernández Mulford und Arnaldo De Jesús Peralta Castilla. „Biological fixation of nitrogen by native isolates of Rhizobium sp. symbionts of Leucaena leucocephala (Lam.) De Wit“. Acta Agronómica 68, Nr. 2 (01.04.2019): 75–83. http://dx.doi.org/10.15446/acag.v68n2.69322.
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Forage legumes such as Leucaena leucocephala, besides being a rich source of protein for animal feed, its inclusion in silvopastoral systems provides fundamental components to improve soil properties. These plants have the ability to establish symbiotic association with the genus Rhizobium sp. and fix biologically atmospheric nitrogen favoring growth and development, being reflected in production increases. The objective of this research was to evaluate the capacity of native isolates of Rhizobium sp. and a commercial strain in biological nitrogen fixation (BNF) in L. leucocephala plants. Two separate bioassays to evaluate the efficiency of the FBN of the native isolates and the commercial strain under greenhouse conditions, followed by a randomized complete block design with 7 x 2 factorial arrangement, seven treatments, two factors: native isolates and commercial strains and bacterial concentrations (106 and 108 cells.ml-1), with three repetitions and five experimental units. The first bioassay was carried out with seeds, determining the percentage of germination, the length and thickness of the stem, number of leaves, dry weight of the aerial part, number of nodule/plant and the percentage of nitrogen accumulated in the area part of the plant. In the second bioassay with 30-day-old seedlings, the same variables of the first bioassay were determined, with the exception of the percentage of germination. In the first bioassay, a greater stimulation was found in the germination of L. leucocephala seeds at a concentration of 108 cells.mL-1. Regarding stem length and thickness, accumulated dry matter, leaf development and nitrogen accumulation, better results were found in the treatments with the native isolates L27, L36 and L38 in a concentration of 106 cells.mL-1 above the commercial strain in concentration of 108 cells.mL-1. The native isolates of Rhizobium sp. exert a positive effect on the FBN and the germination of plants of L. leucocephala, which will allow to conduct future field studies that allow to potentiate the culture of L. leucocephala and silvopastoral systems for bovine feeding.
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Mukaromah, Arnia Sari, Yekti Asih Purwestri und Yoshiharu Fujii. „Determination of Allelopathic Potential in Mahogany (Swietenia macrophylla King) Leaf Litter Using Sandwich Method“. Indonesian Journal of Biotechnology 21, Nr. 2 (28.10.2017): 93. http://dx.doi.org/10.22146/ijbiotech.16456.
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The sandwich method is a reliable screening bioassay that can be utilized to investigate allelopathic activity of leaf litter leachates. Screening the allelopathic potential of mahogany (Swietenia macrophylla King) leaf litter in plant–plant interaction using the sandwich bioassay method has not been reported. The research objectives were to determine and categorize allelopathic potential of S. macrophylla leaf litter using the sandwich bioassay method, and to determine specific activity (EC550). S. macrophylla leaf litter. The results showed that S. macrophylla leaf litter exhibited strong allelopathic activity when compared with 46 leaf litter species and was included in the top ten of allelopathic leaf litter species. Increasing S. macrophylla leaf litter concentration was concomitant with inhibition of radicle lettuce seedling growth compared with the control. According to the linear regression analysis, the effective concentration (EC50) of S. macrophylla was estimated to be 3.25 mg D.W. eq. mL-1 and was considered to have strong growth-inhibitory activity on lettuce radicle elongation. The results suggest the possibility of allelopathic potential of leaf litter in plant–plant interaction under S. macrophylla trees.
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Kubowicz, Dorota, und Ewa Grodzka. „The use of cultivars of Raphanus sativus for cytokinin bioassay“. Acta Agrobotanica 40, Nr. 1-2 (2013): 21–25. http://dx.doi.org/10.5586/aa.1987.003.
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Six cultivars of radish (<i>Raphanus sativus</i>) were tested for their usefulness in radish cytokinin bioassay by the method of <i>Letham</i> (1971). The best cultivar was found to be 'Sopel Lodu' which responds well to both zeatin and 2iP over a wide range of concentrations. The fresh weight of cotyledons increased at most by 71.5% (if treated with zeatin) or 101.0% (if treated with 2iP) compared to untreated cotyledons. This cultivar is also sensitive to the partially purified cytokinin-like fraction isolated from the pine (<i>Pinus silvestris</i>) cambial region. The cultivar 'Sopel Lodu' is therefore proposed to be a suitable plant for cytokinin bioassays.