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Articles 1 - 11 of 11

Full-Text Articles in Life Sciences

Qualitative Characterization Of The Endogenous Cytokinins In Red Pine And Aspects Of Their Influence On Seedling Development , Richard Meilan Jan 1990

Qualitative Characterization Of The Endogenous Cytokinins In Red Pine And Aspects Of Their Influence On Seedling Development , Richard Meilan

Retrospective Theses and Dissertations

Red pine seedlings alternate between root and shoot production in a periodic fashion. This habit is referred to as episodic growth and is assumed to be controlled by endogenous plant growth regulators. This project was concerned with the role played by cytokinins in the control of episodic growth;After confirming the existence of episodic growth in red pine seedlings, a carrier solution was optimized and a series of exogenous application trials was conducted. Only those solutions containing a surfactant and N[superscript]6-benzylaminopurine (BAP) produced an observable response. Foliar applications of BAP induced the formation of an apical cluster of ...


Experimental Evaluation Of An Environmental Conservation Technology Instructional Unit , Linda Susan Whent Jan 1990

Experimental Evaluation Of An Environmental Conservation Technology Instructional Unit , Linda Susan Whent

Retrospective Theses and Dissertations

The study was conducted during the fall and winter of the 1989-1990 school year to evaluate the effectiveness of an environmental conservation technology instructional unit. The instructional unit was designed for upper level high school agriculture science technology and marketing students (ASTM). The effectiveness of the unit was measured in terms of students' knowledge of environmental conservation technology, students' attitude toward natural resources, and teachers' attitudes toward natural resources and teaching environmental conservation technology;An experimental pretest-posttest control group design was used in this study. Schools with ASTM departments were randomly selected and randomly assigned to groups from a population ...


Species Abundance Patterns And Productivity Of Birds Using Grassed Waterways In Iowa Rowcrop Fields, Georgia Gaye Bryan Jan 1990

Species Abundance Patterns And Productivity Of Birds Using Grassed Waterways In Iowa Rowcrop Fields, Georgia Gaye Bryan

Retrospective Theses and Dissertations

No abstract provided.


Productivity And Habitat Preferences Of Loggerhead Shrikes Inhabiting Roadsides In A Midwestern Agroenvironment, David William Degeus Jan 1990

Productivity And Habitat Preferences Of Loggerhead Shrikes Inhabiting Roadsides In A Midwestern Agroenvironment, David William Degeus

Retrospective Theses and Dissertations

No abstract provided.


Ecology Of Gopher Tortoises (Gopherus Polyphemus) On Sanibel Island, Florida , Grace Sheryl Mclaughlin Jan 1990

Ecology Of Gopher Tortoises (Gopherus Polyphemus) On Sanibel Island, Florida , Grace Sheryl Mclaughlin

Retrospective Theses and Dissertations

The city of Sanibel and the Sanibel-Captiva Conservation Foundation (SCCF) have had a long interest in protecting their gopher tortoise populations. It has been illegal to disturb tortoises on Sanibel in any way since 1979, but enforcement has been difficult. Regulations have been established on Sanibel to prevent fences from inhibiting tortoise movements and to set aside 15% of lands being developed for gopher tortoise habitat. There is a substantial need for information on Sanibel tortoises, especially concerning habitat characteristics, population characteristics and trends, and timing of activity (both daily and reproductive) if correct decisions are to be made regarding ...


An Analysis Of Selected Iowa Farmers' Perceptions Regarding Innovation Characteristics And Institutional Factors Influencing The Adoption Of Low-Input Sustainable Agricultural Practices: Implications For Agricultural Extension Education, Adewale Johnson Alonge Jan 1990

An Analysis Of Selected Iowa Farmers' Perceptions Regarding Innovation Characteristics And Institutional Factors Influencing The Adoption Of Low-Input Sustainable Agricultural Practices: Implications For Agricultural Extension Education, Adewale Johnson Alonge

Retrospective Theses and Dissertations

No abstract provided.


Restoration Of Remnant, Native Warm-Season Grasses On Southern Iowa Pastureland, Thomas Robert Rosburg Jan 1990

Restoration Of Remnant, Native Warm-Season Grasses On Southern Iowa Pastureland, Thomas Robert Rosburg

Retrospective Theses and Dissertations

No abstract provided.


Design Considerations In The Reconstruction Of Palustrine Wetlands In The Prairie Pothole Region Of Iowa, Kevin Carl Thomas Jan 1990

Design Considerations In The Reconstruction Of Palustrine Wetlands In The Prairie Pothole Region Of Iowa, Kevin Carl Thomas

Retrospective Theses and Dissertations

No abstract provided.


Iowa's Timber-Based Economy: An Economic Analysis , Stephen Hiama Kolison Jr. Jan 1990

Iowa's Timber-Based Economy: An Economic Analysis , Stephen Hiama Kolison Jr.

Retrospective Theses and Dissertations

The decade of the '80s brought economic difficulties to the state of Iowa. Demand for its traditional products such as corn, soybean, and farm machinery fell sharply. At the moment, there appear to be considerable improvements in the economy relative to previous years in the '80s. Nevertheless, concerns still remain that the economic conditions for the '80s could be repeated. These concerns have generated discussions regarding ways to prepare the state against similar economic recession in its traditional sectors. Prominent among these discussions is the idea of diversifying and expanding the state's economy beyond its traditional products;It was ...


A Physiological Approach To The Sublethal Effects Of Cadmium In Lampsilis Ventricosa , Teresa J. Naimo Jan 1990

A Physiological Approach To The Sublethal Effects Of Cadmium In Lampsilis Ventricosa , Teresa J. Naimo

Retrospective Theses and Dissertations

Previous studies of contaminant effects on freshwater mussels have been restricted to tissue contaminant concentrations and distribution among tissues. Although no standardized toxicity tests are available, acute toxicity tests have been conducted on freshwater mussels. Chronic toxicity tests which mimic the continuous low-level contaminant exposure these organisms may receive in nature are needed. A physiological approach was taken in this study to examine the sublethal effects of cadmium (0, 30, 100 and 300 ug/l) on the metabolic activity of adult Lampsilis ventricosa. A 28-day toxicity test was conducted using a proportional diluter. Ten mussels were placed into each of ...


Herbicide And Tracer Movement In Soil , George Frank Czapar Jan 1990

Herbicide And Tracer Movement In Soil , George Frank Czapar

Retrospective Theses and Dissertations

Field movement of several herbicides, rhodamine WT, chloride, and bromide was measured by sampling field drainage tiles 1.2 m deep. Under natural rainfall conditions, alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide) and metribuzin (4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one) were detected in tile effluent samples 12 to 18 hours after a 30.7 mm rainstorm. Rainfall occurring 1 to 2 days after chemical application was primarily responsible for the elevated concentrations found. In a second experiment, a rainfall simulator was used to apply 50 to 80 mm of water to 8 plots, 24 hours after ...