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1.
The purpose of this study was to examine the genotypic variation in maize doubled haploid (DH) lines response to brassinosteroid and gibberellin inhibitors. Plant responses to hormone inhibitors were determined in growth chamber experiments using germination paper for three different seedling treatments: application of propiconazole (Pcz), uniconazole (Ucz) or water (control). Mesocotyl length (ML) was more sensitive to hormone inhibitors, especially to the Ucz treatment, than other seedling traits. ML was significantly correlated with other traits in the Ucz treatment. All the seedling traits showed moderate-to-high broad sense heritability values, ranging from 0.39 to 0.82. The Euclidian genetic distances of inbred line pairs ranged from 1.27 to 19.94, indicating there was a high level of variability across the maize DH lines used in this study. DH lines with extreme MLs were identified, which can provide valuable breeding resources for improving abiotic stress tolerance, and for further genetic studies. 相似文献
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Jordão RS Ribeiro CP Pituco EM Okuda LH Del Fava C Stefano Ed Filho MM Mehnert DU 《Research in veterinary science》2011,91(2):311-315
Bovine Viral Diarrhea Virus (BVDV) is widespread in cattle in Brazil and research shows its large antigenic variability. Available vaccines are produced with virus strains isolated in other countries and may not be effective. In this study, inactivated vaccines containing the Brazilian BVDV-Ib IBSP11 isolate were developed and tested on 6 groups of 10 guinea pigs (Cavia porcellus). Animals in groups A and C received an aqueous vaccine (aluminum hydroxide); B and D groups received an oily vaccine (Montanide ISA50); Group E positive-control animals were given an imported commercial vaccine with BVDV-Ia Singer; Group F animals were sham vaccinated (negative control). Groups A, B and E received two doses, and Groups C and D, three, every 21 days. Twelve blood samples were taken, at 21-day intervals over 231 days, and evaluated for antibody titer through virus-neutralization (VN), using a homologous strain (IBSP11), and a heterologous strain (BVDV-Ia NADL). Most animals, 42 days following the first dose, seroconverted to both strains and, after the second dose, there was a significant increase of titers in all groups. The oily formulation induced greater response after the third administration. This increase was not observed with the aqueous vaccines, regardless of the virus used in the VN. Antibody decline was more rapid in animals that received aqueous vaccines. The results showed the importance of studying the influence of endemic strains of commercial vaccines, to improve the efficacy of BVD vaccination. Use of the endemic strain in vaccine formulation presented promising results, as well as the use of guinea pigs as a laboratory model. 相似文献
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Walter Oettmeier Ursula Hilp Wilfried Draber Carl Fedtke Robert R. Schmidt 《Pest management science》1991,33(4):399-409
Weeds resistant to the s-triazine herbicide atrazine also show resistance to the triazinone herbicide metribuzin. However, with highly lipophilic triazinones, thylakoids isolated from atrazine-resistant Amaranthus retroflexus (mutation at position Ser264 of the photosystem II D-1 reaction centre protein) in general show a higher pI50 value in photosystem II electron transport than those from the wild type (i.e. negative cross-resistance; ‘supersensitivity’). A quantitative structure–activity relationship (QSAR) can be established, wherein the lipophilicity of the compound plays a major role. In in-vivo experiments, it was found that the triazinone DRW2698 killed resistant Amaranthus retroflexus and Chenopodium album whereas the wild type was almost unaffected. Triazinones were further investigated in five different mutants of Chlamydomonas rheinhardtii (mutations in the D-1 protein at positions Ser264, Ala251, Leu275, Phe255, and Val219). Inhibitory activity of all triazinones was generally enhanced in the Phe255 mutant but decreased in the Val219 mutant. In the other mutants, biological activity was decreased when position 3 of the triazinone was substituted by CH3, OCH3, SCH3, NHCH3 or N(CH3)2. However, negative cross-resistance was again observed when this position was occupied by free thiol. It is therefore suggested that these two groups of triazinones orient themselves differently within the herbicide binding niche of the photosystem II D-1 protein. 相似文献
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Jacqueline W.M. Postma Pål Axel Olsson Ursula Falkengren-Grerup 《Soil biology & biochemistry》2007,39(2):400-408
Colonisation by root endophytes can be beneficial to plants growing on acid, nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi can supply herbs with nutrients and may give protection against aluminium toxicity. Two other root colonising fungi, fine endophytes (FE) and dark septate fungi (DSE), are less well known but are potentially of benefit to their host plant. AM fungi are the most prevalent symbionts in herbs at neutral to acidic soil pH. At extremely low pH, fungal growth can be limited and AM colonisation is usually rare. Fine and dark septate endophytes, on the other hand, have been observed more often under these conditions. In order to relate endophyte colonisation to a gradient in soil pH, we investigated root colonisation by AM, FE and DSE in Maianthemum bifolium, Galium odoratum, Mercurialis perennis and Stellaria nemorum, from a range of acidic beech forests. With decreasing pH, colonisation by AM decreased, whereas the other two endophytes increased. AM and FE colonisation were inversely correlated in Maianthemum bifolium. We compared changes in root colonisation with those in chemical composition of soil and leaf samples and found a positive correlation between leaf magnesium concentrations and the presence of DSE in Galium odoratum. Aluminium concentration in Maianthemum bifolium tended to be lower when FE colonisation was high, suggesting a possible role for the fungi in plant protection against Al. We suggest that FE and DSE may replace AM fungi in herbaceous vegetation at extremely low pH, counteracting some of the negative effects of high soil acidity on plants. 相似文献
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The activity levels of succinate dehydrogenase (SDH) and glucose‐6‐phosphate dehydrogenase (G6PD) were assessed in various tissues of Cyprinus carpio var communis which had been exposed to lethal concentrations of group‐II pyrethroids (deltamethrin, cypermethrin, fenvalerate and fluvalinate) for a period of 72 h. The results indicated a steady decrease in SDH activity with a concomitant increase in G6PD activity. The decreased SDH activity indicated inhibition of SDH at mitochondrial level and the increased G6PD activity an enhancement of an alternative pathway of carbohydrate metabolism, viz the hexose monophosphate shunt (HMP) or pentose phosphate pathway as a biochemical adaptation to overcome the toxic stress. © 2001 Society of Chemical Industry 相似文献
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Ursula Weigt 《Veterinary research communications》1983,7(1):253-257
In 1979, 209 cows from 2742 patients in the clinic for obstetrics and gynecology suffered from coliform mastitis. Most of these animals had been sent to the clinic because of a general or local infectious disease, a delayed birth or a teat injury. Coliform mastitis developed secondarily. Only 12 animals (6%) had solely a mastitis and no other clinically recognisable disease. Most of them showed a secondary acetonemia (ketosis). The connection between hypoglycemia, disturbance of the body's own defense mechanism and development of a coliform mastitis is discussed. The frequent occurrence of coliform mastitis in dairy herds with sawdust bedding is not directly attributed to a coliform contamination of the bedding but indirectly to a lack of crude fibre content in the diet which results in a subclinical ketosis and a dysfunction of the leucocytic defense. Coliform mastitis predominantly is not a hygienic but a management problem. 相似文献
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Gomes MS Sinnecker P Tanaka RT Lanfer-Marquez UM 《Journal of agricultural and food chemistry》2003,51(6):1634-1639
Chlorophyll in soybean represents a downgrading factor for the crops. Five Brazilian cultivars were harvested between R(6) and R(8) stage of development (Fehr & Caviness scale) and dried at 25 degrees and 40 degrees C. The effect of maturity stages and two drying conditions after harvest were studied to achieve reduction of moisture and chlorophylls to acceptable levels. When seeds were dried at 25 degrees C, even harvesting at early stages of development such as R(6), the green pigments were almost degraded, and 16 ppm of chlorophyll were found at maximum, accompanied by loss of moisture. Moisture and chlorophyll declines as seed matures, but at intermediary stages (R(6)-R(7)), chlorophyll degrades first, so the rate of moisture loss should not be used to predict chlorophyll contents. At 40 degrees C, complete degradation of chlorophyll pigments is only achieved when seeds are swathed from R(7) stage up, otherwise the seed quality could be compromised. Slow drying allows almost complete removal of green pigments, even when seeds are swathed a few days before the physiological maturity stage. 相似文献