Designing sustainable agriculture education: Academics’ suggestions for an undergraduate curriculum at a land grant university     

Damian M. Parr  Cary J. Trexler  Navina R. Khanna  Bryce T. Battisti 《Agriculture and Human Values》2007,24(4):523-533

Historically, land grant universities and their colleges of agriculture have been discipline driven in both their curricula and research agendas. Critics call for interdisciplinary approaches to undergraduate curriculum. Concomitantly, sustainable agriculture (SA) education is beginning to emerge as a way to address many complex social and environmental problems. University of California at Davis faculty, staff, and students are developing an undergraduate SA major. To inform this process, a web-based Delphi survey of academics working in fields related to SA was conducted. Faculty from colleges and universities across the US were surveyed. Participants suggested that students needed knowledge of natural and social science disciplines relating to the agri-food system. In addition, stakeholders suggested students learn through experiences that link the classroom to field work, engaging a broad range of actors within applied settings. Stakeholders also emphasized the need for interdisciplinary and applied scholarship. Additionally, they proposed a range of teaching and learning approaches, including many practical experiences. Given the diverse suggestions of content knowledge and means of producing knowledge, the survey presented unique challenges and called into question the epistemological and pedagogical norms currently found in land grant colleges of agriculture. This study has implications for land grant universities seeking to develop undergraduate curriculum appropriate to the field of SA. Damian M. Parr is a doctoral student of Agricultural and Environmental Education, in the School of Education at the University of California at Davis. His professional interests include organic farming, sustainable agriculture, experiential and transformational learning, critical pedagogy, and participatory action research. He is currently working on linking on-campus student initiated sustainable farm and food systems projects to curricula at land grant universities Cary J. Trexler is an assistant professor of Agricultural and Environmental Education at the University of California at Davis where he teaches courses in the history of agricultural education, experiential learning, and research methods for practicing teachers. His research focuses on experiential learning, sustainable agriculture education, and needs of teachers and informal educators within the context of the agri-food system Navina R. Khanna is a graduate student pursuing an MS in International Agricultural Development at the University of California at Davis. She is committed to facilitating community dialogue and education about sustainability issues. Her work at the university focuses on the process and goal of sustainability in agricultural education and campus food system sustainability. Her primary professional interests include democratic participatory process in agri-food system sustainability and urban revitalization Bryce T. Battisti is a doctoral student of Agricultural and Environmental Education, in the School of Education at the University of California at Davis. His research interests include the development of alternative models for university education that are founded on student-centered experiential learning. Specifically, he studies models of permaculture education that lead toward accredited degrees and relates these models to sustainable agriculture degree programs  相似文献   

Effects of relative humidity,oxygen, and carbon dioxide on initiation and early development of stolons and tubers     

John W. Cary 《American Journal of Potato Research》1986,63(11):619-627

Russet Burbank potatoes were grown in the greenhouse to explore the effects of soil O₂, CO₂, and relative humidity on tuberization. The composition of the gas phase surrounding the below ground stem and stolons was controlled at various levels. Prolonged levels of CO₂ greater than 5% produced large lenticels and, in combination with high relative humidity suppressed the number of stolons. Oxygen levels of 5% or less in prolonged contact with the stolons and underground portion of the stem were favorable to stem decay by pathogens but did not affect lenticel size. Isolating the stolons in a low relative humidity environment delayed tuber set, but increased the number of tubers per plant. This effect of low humidity suggests that the onset of tuberization involves at least two inductive factors, one of which is not translocated among stolons.  相似文献   

Use of uniconazole to control plant height for an industrial/pharmaceutical maize platform     

Craig M. SchluttenhoferGioia D. Massa  Cary A. Mitchell 《Industrial Crops and Products》2011,33(3):720-726

A variety of crops and their production systems have been proposed as platforms for plant-made pharmaceuticals (PMPs) and plant-made industrial compounds (PMICs), each with their own advantages and challenges. Maize grown in isolated, confined environments avoids several challenging issues associated with future production of PMPs/PMICs. When grown under optimizing conditions of temperature, nutrition, and water status, however, maize tends to elongate excessively, which contributes to lodging and interferes with delivery of sufficient overhead electric lighting to the inner foliar canopy where ears develop. Suppression of extensive stem elongation without compromising grain yield would help in delivering overhead light into the foliar canopy for efficient grain production. The plant-growth retardant uniconazole (UCZ) was tested for its effects on maize height and grain yield. UCZ reduced plant height effectively, but dosages that strongly suppressed stem elongation also decreased grain yield, ear length, and cob weight. Duration of growth suppression was prolonged at high UCZ concentrations. UCZ also induced branching of maize, which was enhanced as concentrations increased. A range of ear types occurred on branches, with some conversion of ears to tassels at high UCZ concentrations. Minimum stem diameter declined with increasing UCZ concentration. Plant height was reduced from 306 cm to 232 cm (−25%) using a concentration of 1.0 mg/L UCZ without affecting grain yield of 180-200 g per plant. This low UCZ concentration caused 1-2 basal branches to form that would not affect planting density in a cropping situation.  相似文献   

Optimizing environmental conditions for mass application of mechano-dwarfing stimuli to Arabidopsis.     

Jill A Montgomery  Ray A Bressan  Cary A Mitchell 《Journal of the American Society for Horticultural Science》2004,129(3):339-343

Obtaining uniform mechano-dwarfing of Arabidopsis thaliana (L.) Heynh. seedlings within dense plantings is problematic. Alternative forms of mechano-stimulation were applied to seedlings in effort to obtain uniform growth reduction compared with undisturbed controls in both greenhouse and controlled growth environments. Arabidopsis grown under low photosynthetic photon flux (PPF) artificial light grew upright with limited leaf expansion, which enhanced mechano-responsiveness compared to that of rosette-growing plants under filtered sunlight or high PPF artificial light. Hypocotyls of seedlings grown at PPFs > 60 micromoles m-2 s-1 elongated less and had 6% less sensitivity to mechanical stress than seedlings grown at PPFs < 60 micromoles m-2 s-1. Fluorescent lamps alone (F) or fluorescent plus incandescent (F+I) lamps were compared for seedling responses to mechanical stress. Under F lighting, hypocotyl elongation was reduced 25% to 40% by twice-daily brush or plate treatments, and brushed seedlings exhibited more growth reduction than did plate treatments. Seedlings grown under F+I lamps exhibited similar stress-induced growth reduction compared to seedlings grown under F only, but stressed F+I seedlings lodged to a greater extent due to excessive hypocotyl elongation. Temperature-response studies using standardized F-only lighting indicated increased hypocotyl elongation but decreased leaf expansion, and decreased mechano-responsivity to brushing over the temperature range from 20 to 28 degrees C. Daylength studies indicated similar degrees of mechano-inhibition of hypocotyl elongation over the daylength range of 12, 16, 20, and 24 hours, whereas fresh weight of stressed seedling shoots declined compared to controls. A combination of environmental growth parameters that give repeatable, visual mechanical dwarfing of Arabidopsis include low-PPF fluorescent lighting from 55 to 60 micromoles m-2 s-1, ambient temperatures from 22 to 25 degrees C, and twice-daily brush treatments.  相似文献   

Low-temperature synthesis of zintl compounds with a single-source molecular precursor     

MA Beswick  N Choi  CN Harmer  AD Hopkins  M McPartlin  DS Wright 《Science (New York, N.Y.)》1998,281(5382):1500-1501

Thermolysis of the heterobimetallic phosphinidene complex [Sb(PCy)3]2- Li6.6HNMe2 (Cy = C6H11) at 303 to 313 kelvin gives Zintl compounds containing (Sb7)3- anions. The complex thus constitutes a stable molecular single-source precursor to Zintl compounds and provides a potential low-temperature route to photoactive alkali metal antimonates. The new chemical reaction involved, which is driven thermodynamically by the formation of P-P bonds, has implications in the low-temperature synthesis of other technologically important materials (such as gallium arsenide).  相似文献   

Exploring the key drivers of forest flammability in wet eucalypt forests using expert-derived conceptual models     

Cawson  Jane G.  Hemming  Victoria  Ackland  Andrew  Anderson  Wendy  Bowman  David  Bradstock  Ross  Brown  Tegan P.  Burton  Jamie  Cary  Geoffrey J.  Duff  Thomas J.  Filkov  Alexander  Furlaud  James M.  Gazzard  Tim  Kilinc  Musa  Nyman  Petter  Peacock  Ross  Ryan  Mike  Sharples  Jason  Sheridan  Gary  Tolhurst  Kevin  Wells  Tim  Zylstra  Phil  Penman  Trent D. 《Landscape Ecology》2020,35(8):1775-1798

Landscape Ecology - Fire behaviour research has largely focused on dry ecosystems that burn frequently, with far less attention on wetter forests. Yet, the impacts of fire in wet forests can be...  相似文献   

Electrothermal atomic absorption spectroscopic determination of chromium in plant tissues     

E E Cary  M Rutzke 《Journal of the Association of Official Analytical Chemists》1983,66(4):850-852

This method involves sample digestion in nitric, perchloric, and sulfuric acids. Chromium is concentrated by coprecipitation with ferric hydroxide. Redissolved iron is removed by liquid-liquid extraction, remaining silica is dissolved with hydrofluoric acid, and chromium is determined by electrothermal atomic absorption spectrometry. The sensitivity and detection limits for chromium approach those given by the manufacturers of the various instruments. Recovery studies and analysis of standard materials show that this method is reliable.  相似文献   

Importance of fuel treatment for limiting moderate-to-high intensity fire: findings from comparative fire modelling     

Geoffrey J. Cary  Ian D. Davies  Ross A. Bradstock  Robert E. Keane  Mike D. Flannigan 《Landscape Ecology》2017,32(7):1473-1483

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Fidelity of a simple Liberty leaf-painting assay to validate transgenic maize plants expressing the selectable marker gene,bar     

K. Rajasekaran  R. Majumdar  C. Sickler  Q. Wei  J. Cary  D. Bhatnagar 《Journal of Crop Improvement》2017,31(4):628-636

Screening of gene manipulation events (transgenic, mutation/genome editing, etc.) is a cost/labor-intensive and time-consuming process in plant science research. While polymerase chain reaction (PCR) is the most commonly used method for screening, the process still requires efficient DNA extraction and subsequent confirmation. However, PCR cannot predict gene expression. To screen a larger number of transgenic plants, it would be ideal to develop a quick and reliable screening procedure. We have applied a Liberty^® leaf-painting method (against bar gene under 4x35S promoter) to screen transgenic maize (Zea mays L.) plants and validated the results through PCR and quantitative real-time PCR (qRT-PCR). Liberty leaf painting at 500 mg L^?1a.i. was > 95% accurate in identifying transgenic events that agreed with the PCR results. Further investigation of bar gene expression in sensitive lines that were PCR positive shows very low expression of the bar gene. We have provided a simple, and rapid assay to determine the transgene expression potential of maize plants expressing the bar gene. The herbicide can be applied to a fully expanded leaf and evaluated one week after application. Green or partially green leaf blades indicate high or moderately high expression of the bar gene and a total yellowing indicates absence or extremely low expression of the bar gene in the transgenic plants. A small volume of Liberty solution is adequate to test hundreds of maize plants, and the assay is reproducible with a high frequency (> 95%) and also displays good correlation with gene expression in planta.  相似文献   

Soil oxygen and moisture in relation to Russet Burbank potato yield and quality     

C. B. Holder  J. W. Cary 《American Journal of Potato Research》1984,61(2):67-75

On a Declo loam, rooting density, final yield and quality of potatoes (Solarium tuberosum cv. Russet Burbank) showed no significant differences among conventional planting, ripping along the row, or forced aeration 30 cm below the top of the row. There were significant relationships between oxygen diffusion rate (ODR) and soil moisture tension (matric potential) at the 30 and 40 cm depths, but these relationships were not significantly different among treatments. In a complementary experiment, sprinkler irrigations at negative soil water matric potentials of 30–40 (wet), 40–50 (intermediate) and 50–60 kPa (dry,i.e., 0.5–0.6 bar tension) produced no differences in total yield. However, the wet treatment gave significantly more knobby and undersized tubers < 113 g (4 oz.) and a lower percentage of U.S. #1 tubers than the intermediate and dry treatments. Premium sized tubers > 284 g (10 oz.) were significantly higher in the dry than in the wet treatment. Fertilizer N was applied periodically during the season and petiole NO₃-N levels indicated adequate levels with no differences among treatments in either experiment. So much attention has been given to the effects of drought and high temperature stress on the quality of Idaho Russet Burbank potatoes, that some growers may now over-irrigate. Results of this research indicate that attention should also be directed to the effects of excess moisture on the size and quality of tubers.  相似文献