1,014 research outputs found
Abnormal flowers and pattern formation in floral
“From our acquaintance with this abnormal enabled to unveil the secrets that normal us, and to see distinctly what, from the regular we can only infer.” - J. W. von Goethe (1790
Genetic interactions among floral homeotic genes of Arabidopsis
We describe allelic series for three loci, mutations in which result in homeotic conversions in two adjacent whorls in the Arabidopsis thaliana flower. Both the structure of the mature flower and its development from the initial primordium are described by scanning electron microscopy. New mutations at the APETALA2 locus, ap2-2, ap2-8 and ap2-9, cause homeotic conversions in the outer two whorls: sepals to carpels (or leaves) and petals to stamens. Two new mutations of PISTILLATA, pi-2 and pi-3, cause second and third whorl organs to differentiate incorrectly. Homeotic conversions are petals to sepals and stamens to carpels, a pattern similar to that previously described for the apetala3-1 mutation. The AGAMOUS mutations, ag-2 and ag-3, affect the third and fourth whorls and cause petals to develop instead of stamens and another flower to arise in place of the gynoecium. In addition to homeotic changes, mutations at the APETALA2, APETALA3 and PISTILLATA loci may lead to reduced numbers of organs, or even their absence, in specific whorls. The bud and flower phenotypes of doubly and triply mutant strains, constructed with these and previously described alleles, are also described. Based on these results, a model is proposed that suggests that the products of these homeotic genes are each active in fields occupying two adjacent whorls, AP2 in the two outer whorls, PI and AP3 in whorls two and three, and AG in the two inner whorls. In combination, therefore, the gene products in these three concentric, overlapping fields specify the four types of organs in the wild-type flower. Further, the phenotypes of multiple mutant lines indicate that the wild-type products of the AGAMOUS and APETALA2 genes interact antagonistically. AP2 seems to keep the AG gene inactive in the two outer whorls while the converse is likely in the two inner whorls. This field model successfully predicts the phenotypes of all the singly, doubly and triply mutant flowers described
Simulation of charged particle trajectories in the neutron decay correlation experiment abBA
The proposed neutron decay correlation experiment, abBA, will directly detect the direction of emission of decay protons and electrons as well as providing spectroscopic information for both particles. In order to provide this information, the abBA experiment incorporates spatially varying electric and magnetic fields. We report on detailed simulations of the decay particle trajectories in order to assess the impact of various systematic effects on the experimental observables. These include among others; adiabaticity of particle orbits, tracking of orbits, reversal of low energy protons due to inhomogeneous electric field, and accuracy of proton time of flight measurements. Several simulation methods were used including commercial software (Simion), custom software, as well as analytical tools based on the use of adiabatic invariants. Our results indicate that the proposed field geometry of the abBA spectrometer will be substantially immune to most systematic effects and that transport calculations using adiabatic invariants agree well with solution of the full equations of motion
Control of flower development in Arabidopsis thaliana by APETALA1 and interacting genes
Mutations in the APETALA1 gene disturb two phases of flower development, flower meristem specification and floral organ specification. These effects become manifest as a partial conversion of flowers into inflorescence shoots and a disruption of sepal and petal development. We describe the changes in an allelic series of nine apetala1 mutants and show that the two functions of APETALA1 are separable. We have also studied the interaction between APETALA1 and other floral genes by examining the phenotypes of multiply mutant plants and by in situ hybridization using probes for several floral control genes. The results suggest that the products of APETALA1 and another gene, LEAFY, are required to ensure that primordia arising on the flanks of the inflorescence apex adopt a floral fate, as opposed to becoming an inflorescence shoot. APETALA1 and LEAFY have distinct as well as overlapping functions and they appear to reinforce each other's action. CAULIFLOWER is a newly discovered gene which positively regulates both APETALA1 and LEAFY expression. All functions of CAULIFLOWER are redundant with those of APETALA1. APETALA2 also has an early function in reinforcing the action of APETALA1 and LEAFY, especially if the activity of either is compromised by mutation. After the identity of a flower primordium is specified, APETALA1 interacts with APETALA2 in controlling the development of the outer two whorls of floral organs
The Ursinus Weekly, December 2, 1918
Demobilization of the Student Army Training Corps • Muhlenberg routs Ursinus in final game • Venetian musicians give delightful entertainment • Bill creating a national department of education • Fall meeting of the Directors • Letter from Lieutenant John R. Bowman, B.S.,\u2718 • The shortage of teachers • Reserve team loses to Hill School, 20-0 • S. A. T. C. notes • Inter-platoon basketball gamehttps://digitalcommons.ursinus.edu/weekly/2506/thumbnail.jp
The ABC model of flower development: then and now
In 1991, we published a paper in Development that proposed
the ABC model of flower development, an early contribution to
the genetic analysis of development in plants. In this, we used a
series of homeotic mutants, and double and triple mutants, to
establish a predictive model of organ specification in developing
flowers. This model has served as the basis for much subsequent
work, especially towards understanding seed plant evolution.
Here, we discuss several aspects of this story, that could be a
much longer one. One surprising conclusion is that materials and
methods that might have led to similar work, and to the same
model, were available 100 years before our experiments, belying
the belief that progress in biology necessarily comes from
improvements in methods, rather than in concepts
IMPLEMENTATION OF PESTICIDE APPLICATOR CERTIFICATION SCHOOLS AND CONTINUING EDUCATION WORKSHOPS
The Oklahoma Department of Transportation's (ODOT) herbicide applicator training program consists of initial pesticide applicator training schools followed by independent Certification testing and then on-going yearly continuing education workshops. In support of this on-going effort three pesticide applicator initial certification schools were conducted by Oklahoma State University (OSU) extension staff in fall of 2012 to train a total of 128 ODOT participants. All of the attendees at these workshops took the Core as well as Right of Way Certification exams administered by the Oklahoma Department of Agriculture, Food & Forestry (ODAFF). Seventy-nine percent (101 participants) passed both the Core and Category 6 (Right-of-Way) examinations to become Oklahoma Certified Pesticide Applicators. Fourteen Pesticide Applicator Continuing Education (CEU) Workshops were conducted by OSU extension staff across a total of eight ODOT Field Divisions in 2013 to provide 640 Certified Applicators with continuing education training. Records of participation in ODAFF approved CEU programs by ODOT personnel were furnished to ODAFF as well as the ODOT Field Divisions, the Maintenance Division Headquarters and the Planning and Research Division. Participation in CEU workshops resulted in granting of CEU credit to ODOT participants in the workshops. The ODOT participants also gained knowledge on various Integrated Pest Management (IPM) and Integrated Vegetation Management (IVM) products, topics and techniques. This increase or maintained operational knowledge of the participants should insure continued effective vegetation management skills.Final report, October 2012-December 2013N
DELIVERY OF CALIBRATION WORKSHOPS COVERING HERBICIDE APPLICATION EQUIPMENT
Proper herbicide sprayer set-up and calibration are critical to the success of the Oklahoma Department of Transportation (ODOT) herbicide program. Sprayer system set-up and calibration training is provided in annual continuing education herbicide workshops offered by the Oklahoma State University (OSU) Roadside Vegetation Management Program. Although pesticide applicator continuing education (CEU) workshops are offered yearly, equipment calibration is not discussed in CEU workshops in the depth of detail that can be undertaken with on-site. Four ODOT herbicide applicator sprayer calibration workshops were conducted for ODOT in 2013. Sixty-five newly certified ODOT applicators received in-depth training on sprayer equipment calibration. The final decision regarding the capabilities of ODOT employees assigned to specific spray duties should continue to be made by supervisors familiar with each employee. The OSU-RVM professional staff also encourages supervisors and spray crews to thoroughly review spray system setup, annual spray application goals, specific target weed complexes, herbicides to be utilized and sensitive crop or sensitive area locations immediately prior to the beginning of each spray season. Participants in our joint project training effort are encouraged to attend annual pesticide applicator CEU workshops presented by the OSU-RVM Program.Final report, October 2012-December 2013N
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