Amelioration of aluminum toxicity to sorghum seedlings by chelating agents     

L. M. Shuman  D. O. Wilson  E. L. Ramseur 《Journal of plant nutrition》2013,36(2):119-128

At the pH levels found in acid soils (4.5 to 5.5), theoretical equilibrium models predict that Al will be complexed on a nearly one to one molar basis by NTA, EGTA. oxalate (OX) and citrate (CIT). Growth chamber experiments were initiated using solutions containing Al (0, 2, or 10 μM), Ca (400 μ.M). and a chelate (0 or 10 μM) growing sorghum [Sorghum bicolor (L.) Moench cv. AT×399 × RT×430] for four days following germination to test the equilibrium models. The pH and concentration of Al in the solutions were measured before and after each experiment. Plant root length and weight, and shoot weights were used as a bioassay for the uncomplexed, toxic Al. Root length showed the greatest response to aluminum and chelate treatments, although root weight and shoot weight gave the same general results. Chelate effectiveness in reducing Al toxicity was NTA > OX = CIT > EGTA. The pH values were altered very little by NTA or EGTA and averaged 5.2 to 5.3; however, the pH was raised 0.2 to 0.9 units by OX and CIT. Thus, some detoxifying effect from the latter two could be a pH effect. No chelate effect was evident at pH values near 6 for CIT, but the chelate was effective in reducing Al toxicity at pH 5.6, indicating the importance of pH in Al toxicity. NTA alone did not affect root length, but the other chelates all decreased root length to a small degree at 0 μM Al indicating that the chelate itself was detrimental to growth. It was concluded that NTA was an effective chelate to detoxify Al and EGTA was not. Also it was found that OX and CIT behave quite differently from NTA and EGTA in that they affect pH and lower solution Al concentration. The method did not confirm the equilibrium models for EGTA, OX, or CIT because of complicating factors such as pH variation and damage to the roots by the chelates. The equilibrium model for NTA, though, was confirmed.  相似文献   

Integrating a host-resistance factor into the FAST system to forecast early blight of potato     

Joel L. Shuman  Barbara J. Christ 《American Journal of Potato Research》2005,82(1):9-19

A host resistance factor was integrated into the FAST (Forecaster ofAlternariasolani onTomatoes) system to initiate and to schedule fungicide applications for three levels of potato cultivar susceptibility while maintaining disease control and yield. Four cultivars ranging from susceptible to moderately resistant were each treated with the fungicide chlorothalonil during two field seasons. The five fungicide treatments were a 7-day schedule initiated after 50% flowering; a non-sprayed control; and three FAST application schedules based on combinations of critical levels of cumulative severity (CS, the disease severity values as a function of leaf wetness and temperature) and cumulative rating (CR, the disease rating values as a function of average temperature and hours of relative humidity greater than 90%) values. The FAST system predicted the onset of early blight and subsequent periods conducive for disease development in 1993 and 1994. There were cultivar-by-spray-schedule interactions for both disease severity and yield, suggesting that differences in early blight sus-ceptibility exist between cultivars. Use of the recommended schedules for the cultivar’s targeted level of susceptibility reduced early blight severity and minimized fungicide use while maintaining yield. These results indicate that a host-resistance factor can be incorporated into the FAST system.  相似文献   

Comparison of student performance after lecture-based and case-based/problem-based teaching in a large group   总被引：1，自引：0，他引：1  

Grauer GF  Forrester SD  Shuman C  Sanderson MW 《Journal of veterinary medical education》2008,35(2):310-317

The purpose of this study was to compare traditional lecture-based (LB) and case-based/problem-based (CB/PB) learning in a large group. Year 3 veterinary students at Kansas State University were asked to participate in a randomized controlled study. Students were grouped and randomly assigned to be taught by a CB/PB or a LB method. Students took identical multiple-choice examinations, one given within a week of the last class and a different one given four months later. There was no direct effect of teaching method on group scores for either examination. CB/PB students scored higher on higher-difficulty questions on the first examination (p < 0.003), but there was no effect on questions of lower and medium difficulty. There was no effect of teaching method on student performance for the second examination; however, the question difficulty category scores were all different (p < 0.017). Evaluation of examination scores suggests that the two teaching methods were of similar efficacy.  相似文献   

Swine abscesses caused by Lancefield's group E streptococci. IV. Test of two bacterins for immunization   总被引：1，自引：0，他引：1  

R D Shuman  R L Wood 《The Cornell veterinarian》1968,58(1):21-30

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Swine abscesses caused by Lancefield's group E streptococci. XI. Application of the hemagglutination test to demonstrate a correlation between the antigens of group E and streptococcus uberis, and their relation to antibodies induced by unknown organisms   总被引：1，自引：0，他引：1  

G E Wessman  R D Shuman 《The Cornell veterinarian》1973,63(4):618-629

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Characterization of peripheral blood and pulmonary leukocyte function in healthy foals     

Flaminio MJ  Rush BR  Davis EG  Hennessy K  Shuman W  Wilkerson MJ 《Veterinary immunology and immunopathology》2000,73(3-4):267-285

Studies in infants and foals indicate an age-dependent maturation of peripheral lymphocyte subsets. The age-dependent relationship for maturation of cellular immune responses, such as phagocytosis and lymphocyte responses of the peripheral and pulmonary-derived leukocytes, has not been characterized in foals. Lymphocyte subpopulations, mitogen stimulation response of lymphocytes, lymphokine-activated killing cell activity, phagocytosis and oxidative burst activity, and serum immunoglobulin (Ig) classes G and M concentrations were determined in developing foals. This study illustrates age-dependent changes in immunoglobulin class concentrations, lymphocyte subsets, and EqMHC Class II expression in cells of the peripheral blood and lungs of developing neonatal-to-weanling foals. The increase in peripheral blood and BAL B-lymphocytes and serum immunoglobulins in developing foals suggests expansion of immune cell populations during a time in which environmental pathogen exposure is great. General immune function, mitogenic responses, LAK cell activity, opsonized phagocytosis, and oxidative burst activity of newborns was similar to the adult horse. Total immune-cell numbers, rather than function, seemed to be the limiting factor in the development of the equine neonatal immune system. There was an age-related percent increase in the appearance of pulmonary lymphocytes, but a percent decrease in macrophages. Although development of the respiratory immune system follows changes in the peripheral blood, cellular expansion, activation, and migration may occur at a slower pace, making the respiratory environment susceptible to pathogens prior to optimal immune system maturity.  相似文献   

Zinc Forms and Plant Availability in a Compost Amended Soil     

Shuman  L. M.  Dudka  S.  Das  K. 《Water, air, and soil pollution》2001,128(1-2):1-11

Compost can be used to remediate metal-contaminatedsites because it binds metals and reduces metal uptakeby plants. A greenhouse experiment was conducted totest the effectiveness of compost to remediate Zntoxicity to plants and to determine its effect on zinc(Zn) distribution among operationally defined forms. Cecil soil (Typic kanhapludults) was amendedwith 0 to 5000 mg kg^-1 Zn and biosolid compost at0, 100, and 300 tons ha^-1, and then corn (Zea mays L.) was planted. After 42 days of growthplants were weighed and analyzed for Zn concentration. Soil was analyzed for Mehlich 1-extractable Zn andfractionated by a sequential extraction procedure forforms of Zn. Compost lowered soil pH while increasingCEC, exchangeable hydrogen and percent carbon. Concentrations of Mehlich 1-extractable Zn weredecreased by compost addition. Compost additionsdecreased plant Zn concentration and allowed moreplant survival with toxic levels of soil Zn. Compostamendment redistributed Zn from the water soluble andexchangeable fractions to the manganese oxide andamorphous iron oxide fractions, which shows a changein form of Zn from more plant available to less plantavailable. Biosolid compost soil amendments decreaseplant availability of Zn making it less toxic toplants even where it decreases soil pH, which wouldtend to have the opposite effect.  相似文献   

Analysis of decomposition products of pesticides     

M V Kennedy  B J Stojanovic  F L Shuman 《Journal of agricultural and food chemistry》1972,20(2):341-343

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Sensitization by Erysipelothrix rhusiopathiae (insidiosa) with relation to arthritis in pigs. V. Pretreatment with live cells and challenge with homologous, heterologous, or isologous live cells     

R D Shuman  R L Wood  W S Monlux 《The Cornell veterinarian》1965,55(4):523-534

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Screening wheat and sorghum cultivars for aluminum sensitivity at low aluminum levels     

L. M. Shuman  D. O. Wilson  R. R. Duncan 《Journal of plant nutrition》2013,36(12):2383-2395

Screening cultivars for aluminum (Al) tolerance is often conducted in acid soils or in complete nutrient solutions. The former method lacks precise measurements of Al, and the second requires high Al concentrations because of precipitation and chelation of the Al and is less representative of the actual environmental stresses to which plants must adapt. These experiments were designed to determine Al tolerance of wheat (Triticum aestivum L. em Thell) and sorghum (Sorghum bicolor L. Moench) using incomplete solutions with very low Al concentrations. Six wheat and five sorghum cultivars were screened for Al tolerance in solution culture with 0 to 10 μM Al and only Ca, K, Mg, NO₃, and Cl in the solutions. Plants were subjected to the solutions for 4 d, and the change in relative root length was measured. Solution Al levels and pH were measured after the termination of the experiments. ‘Atlas’ 66 and ‘Stacy’ were the most tolerant wheat cultivars ('Atlas 66’ = ‘Stacy’ ≥ ‘Monon’ ≥ ‘Scout 66’ ≥ ‘Arthur 71’ = ‘Oasis'). The wheat cultivars were effectively separated on a genetic response basis at 2 μM Al. Sorghum cultivars were uniform in their Al tolerance, but did show some separation at 1 μM Al (SC56 > Tx430 > ‘Funk GS22DR’ > SC283 = SC599). The pH and Al variations did not account for any of the differences observed, indicating that root length differences were caused by genetic control of response to high Al.  相似文献