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Retrospective Theses and Dissertations

Environmental Sciences

Forestry (Forest biology-wood science)

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Full-Text Articles in Life Sciences

Desiccation And Nitrous Oxide Storage Effects On The Recalcitrant Seeds Of Quercus Alba And Q Macrocarpa , Valasia Iakovoglou Jan 2005

Desiccation And Nitrous Oxide Storage Effects On The Recalcitrant Seeds Of Quercus Alba And Q Macrocarpa , Valasia Iakovoglou

Retrospective Theses and Dissertations

Sensitivity to desiccation of recalcitrant seeds of the Leucobalanus subgenus of Quercus poses limitations to successful storage and regeneration efforts. My three studies evaluated different aspects of these problems. The first study investigated the effect of parent tree and seed size on seedling performance and morphology over the first three months of growth for Quercus alba and Quercus macrocarpa. The second study evaluated the effect of nitrous oxide (N2O) on seed storage as measured by seed, seedling, and starch thermal variables. Seeds from both species were placed in containers with one of three treatments: air, 80/20% and 98/2 ...


Genetic And Environmental Effects On Rooting Ability Of Dormant Unrooted Hybrid Poplar Cuttings , Ronald S. Zalesny Jr. Jan 2003

Genetic And Environmental Effects On Rooting Ability Of Dormant Unrooted Hybrid Poplar Cuttings , Ronald S. Zalesny Jr.

Retrospective Theses and Dissertations

Genotypes with enhanced rooting ability are crucial for deployment of intensively cultured Populus plantations. Rooting of dormant, unrooted cuttings is the first biological prerequisite to stand establishment. The primary objective was evaluating three developmental systems affected by site conditions: lateral and adventitious root ontogenies, root/shoot growth rates, and temperature dependent physiologies. The study tested rooting ability of 21 clones from five taxonomic backgrounds ((Populus deltoides x Populus trichocarpa) x P. deltoides 'BC1'; P. deltoides 'D'; P. deltoides x Populus maximowiczii 'DM'; P. deltoides x Populus nigra 'DN'; P. nigra x P. maximowiczii 'NM') at Ames, Iowa; Waseca, Minnesota; and ...


Soybean-Based Wood Adhesives For Structural Panels , In Yang Jan 2002

Soybean-Based Wood Adhesives For Structural Panels , In Yang

Retrospective Theses and Dissertations

Recent research attention has focused on soybean-based adhesives because of increased phenolic resin prices and adhesive demand. This study was conducted to investigate the adhesive properties of crosslinked soy flour and/or soy hydrolyzate with phenol-formaldehyde (PF) resins for use in structural panels. Neutral phenolic soy (NPS) and alkaline phenolic soy (APS) resins were prepared and used to bond southern pine plywood. Adhesive bond quality of the soybean-based phenolic resins was evaluated by glueline shear test following the procedure detailed in Product Standard PS 1-95 for construction and industrial plywood. Within the range of variable levels investigated, the following conditions ...


Biomass, Carbon, Nitrogen And Soil Respiration Dynamics Within Riparian Buffers And Adjacent Crop Fields , Aydin Tufekcioglu Jan 2000

Biomass, Carbon, Nitrogen And Soil Respiration Dynamics Within Riparian Buffers And Adjacent Crop Fields , Aydin Tufekcioglu

Retrospective Theses and Dissertations

Natural and re-established riparian buffers reduce nonpoint-source pollutants derived from upland agricultural lands and enhance terrestrial and aquatic habitat. This study was conducted in multi-species riparian buffers, cool-season grass buffers and adjacent crop fields to determine biomass, carbon, nitrogen and soil respiration dynamics. The multispecies buffers were composed of poplar (Populus x euroamericana' Eugenei ) and switchgrass (Panicum virgatum L.). Crop fields were under annual corn-soybean rotation. Aboveground biomass was determined by clipping grasses in 25 x 25 cm quadrats. The dynamics of fine (0--2 mm) and small roots (2--5 mm) were assessed by sequentially collecting 5.4 cm diameter, 35 ...


Effectiveness Of A Multi-Species Riparian Buffer System For Sediment And Nutrient Removal , Kye-Han Lee Jan 1999

Effectiveness Of A Multi-Species Riparian Buffer System For Sediment And Nutrient Removal , Kye-Han Lee

Retrospective Theses and Dissertations

Nonpoint source (NPS) pollution from agricultural areas is one of the most critical problems threatening the nation's water resources. Surface runoff is a major carrier of NPS pollutants. Riparian buffers have been proposed as a means of reducing transport of NPS pollutants from agricultural areas to streams. Using rainfall simulation techniques and natural runoff monitoring, plot studies were conducted to evaluate the ability of an established multi-species riparian buffer system to reduce sediment and nutrient in agricultural runoff. The buffer system evaluated contained three types of vegetation: cool-season grasses, warm-season grasses, and woody plants. Results indicated that the effectiveness ...


The Poplar-Leaf Rust Pathosystem: Inheritance Of Resistance And Pathogenic Variability , Girma Melesse Tabor Jan 1998

The Poplar-Leaf Rust Pathosystem: Inheritance Of Resistance And Pathogenic Variability , Girma Melesse Tabor

Retrospective Theses and Dissertations

Among diseases that cause serious yield reduction on Populus deltoides is leaf rust caused by Melampsora medusae. The objectives of this project were to study the pathogenic variability of M. medusae, the genetic basis of inheritance of M. medusae resistance in a family of P. deltoides; and to identify molecular markers linked to a leaf-rust resistant locus. Three pathotypes of M. medusae were identified on the basis of their differential reaction to three Populus clones. Pathotypes D-93, F-93, and IL-48 were compatible with clone 1-488 (P. X euramericana). F-93 and IL48 were also compatible with clone 57-276 (P. deltoides X ...


Pasture Soils In The Tropical Moist Life Zone Of Costa Rica: Implications For Secondary Forest Succession , James Weeks Rosacker Jan 1995

Pasture Soils In The Tropical Moist Life Zone Of Costa Rica: Implications For Secondary Forest Succession , James Weeks Rosacker

Retrospective Theses and Dissertations

A study was conducted in the Tropical Moist Forest Premontane Life Zone in the Puriscal area of Costa Rica to examine differences in soil characteristics in the upper 15 cm of twenty-four paired plots of undisturbed primary forest and pasture. Bulk density and pH were different between the forest and pasture plots. Clay content, total organic carbon and total nitrogen were not different. The twenty-four pasture plots were divided into three erosion groups. There were differences in clay content, organic carbon and total nitrogen between the groups. Clay content of the pasture plots increased with increased erosion, while organic carbon ...


Advanced Biotechnological Approaches And Gene Manipulation In Populus Species , Hoduck Kang Jan 1994

Advanced Biotechnological Approaches And Gene Manipulation In Populus Species , Hoduck Kang

Retrospective Theses and Dissertations

The biotechnology of plant tissue culture has been developed as an applied science for micropropagation, tree improvement, and basic physiology studies. Biotechnological approaches in forest science are advanced as a desirable tool to obtain superior genotypes and to screen for insect resistance. As a basic technique, in vitro cloning is a powerful tool using different explant types such as immature ovules or stem nodes for tree improvement. Typically, plants can be regenerated in vitro by apical or vascular cambial meristems. Genetic transformation is another option to improve the variable lines by genetic modification in host genetic materials with desirable traits ...


Microbeam Methods For Assessing The Distribution Of Preservatives In Wood , Glenn M. Oren Jan 1994

Microbeam Methods For Assessing The Distribution Of Preservatives In Wood , Glenn M. Oren

Retrospective Theses and Dissertations

Compositional images constructed from characteristic x-ray signals generated within the electron microscope possess key advantages over traditional energy dispersive static probe analyses or conventional analog x-ray dot maps for assessing elemental distribution in preservative-treated wood. Digital images are produced by "stepping" the electron beam across the sample in a prescribed format and collecting x-ray information at each pixel point of the array. The various elements present are displayed on a cathode ray tube (CRT), and the peak intensities are stored on disk for subsequent processing and analysis. By assigning a different color to each element, images are produced that correspond ...


In Vitro Culture Systems Of Hybrid Aspen As Tools For Tree Improvement Programs And Commercial Applications , Sung Ho Son Jan 1991

In Vitro Culture Systems Of Hybrid Aspen As Tools For Tree Improvement Programs And Commercial Applications , Sung Ho Son

Retrospective Theses and Dissertations

Tree improvement programs have two important components: (1) induction of desirable types of genetic variation by breeding, and (2) selection and maintenance of the traits by sexual or asexual propagation methods. By combining tissue culture systems and morden DNA technology with conventional breeding methods, both aspects of tree improvement will benfit. New tissue culture systems are also important to the development of commercial applications of improved trees;Therefore, several new approaches to the in vitro culture of hybrid aspen (Populus alba L. x P. grandidentata Michx. 'Crandon') were studied. To investigate multiple shoot regeneration capacity of different cells, tissues, and ...


Provenance Variation And Genotype X Environment Interaction In Sesbania Sesban (L) Merill , Risper Nyagoy Nyong'o Jan 1991

Provenance Variation And Genotype X Environment Interaction In Sesbania Sesban (L) Merill , Risper Nyagoy Nyong'o

Retrospective Theses and Dissertations

Studies involving several accessions of Sesbania sesban were undertaken in the laboratory, nursery and field. The laboratory study was carried out at Iowa State University to determine the best pretreatment methods for sesban's seeds, based on four provenances. There were varying responses among the provenances to the different pretreatment methods. A 1-hour soak in hot water of an initial 100°C was recommended because it had the best general effect;At the Moi University Nursery, Eldoret, Kenya, an inoculation study was undertaken to determine symbiotic effectiveness among 12 accessions of S. sesban. Effects were measured in height growth, leaf ...


Ecology And Management Of Mahogany (Swietenia Macrophylla King) Regeneration In Quintana Roo, Mexico , Patricia Negreros-Castillo Jan 1991

Ecology And Management Of Mahogany (Swietenia Macrophylla King) Regeneration In Quintana Roo, Mexico , Patricia Negreros-Castillo

Retrospective Theses and Dissertations

Six aspects of the ecology and management of mahogany (Swietenia macrophylla King) regeneration in Quintana Roo, Mexico, were studied: (1) the effect of partial overstory removal on natural regeneration; (2) the development of a thinning simulation program, "ThinSim"; (3) a comparison of four methods to kill trees for partial overstory removal; (4) the survival of mahogany seedlings one year after a partial overstory removal; (5) the growth of some tropical trees species three years after a partial overstory removal; and (6) the sprouting capability of seventeen tropical tree species;Natural regeneration of commercially valuable species in tropical forests represents a ...


Influence Of Root System Morphology And Site Characteristics On Development Of Transplanted Northern Red Oak (Quercus Rubra L.) Seedlings , Janette R. Thompson Jan 1991

Influence Of Root System Morphology And Site Characteristics On Development Of Transplanted Northern Red Oak (Quercus Rubra L.) Seedlings , Janette R. Thompson

Retrospective Theses and Dissertations

The purpose of this study was to evaluate the performance of one-year-old red oak seedlings with graded root systems on different sites, to determine if initial root system morphology would influence seedling survival and growth, and to determine whether differences in root system quality would be important over time regardless of outplanting site characteristics. Nursery-run bare-root northern red oak seedlings from the Iowa Department of Natural Resources State Forest Nursery in Ames were graded according to numbers of large first-order lateral roots and outplanted in spring, 1987, on nine plots distributed among three sites in central Iowa;Annual counts of ...


Biotechnology Applications Of Populus Micropropagation , Young Woo Chun Jan 1987

Biotechnology Applications Of Populus Micropropagation , Young Woo Chun

Retrospective Theses and Dissertations

Six aspects involved in biotechnology applications of Populus alba x P. grandidentata micropropagation were studied: (1) the influences of medium consistency and shoot density on in vitro shoot proliferation, (2) protoplast isolation and culture of in vitro cultured leaf explants, (3) morphogenetic potential of in vitro cultured leaf, internode, and root explants, (4) influences of subculturing period and different culture media on cold storage of the plantlets, (5) in vivo and in vitro polyploidy induction, and (6) transformation by an Agrobacterium binary vector;For achieving optimum in vitro shoot proliferation from axillary bud culture, liquid medium and shoot density were ...


Regeneration Ecology Of Oak In Eastern Iowa , Kimberly Dean Coder Jan 1985

Regeneration Ecology Of Oak In Eastern Iowa , Kimberly Dean Coder

Retrospective Theses and Dissertations

Oak (principally Quercus alba L. and Q. rubra L.) regeneration is a major problem in eastern Iowa forests and throughout the central hardwoods. To identify major site and/or species constraints on oak reproduction, 133 one-acre (0.4047 hectare) plots were established, measured, and decribed in seven of the most heavily forested counties of eastern Iowa. Clustering, discrimination, principal component, and stepwise multiple regression multivariate analyses were utilized to isolate reproductive constraints. Additionally, an integration technique to identify potential survival expectations, and a successful modelling technique (corrected for expected survival and checked by Markov chaining), were completed to better understand ...


Soil Autecology Of The Nitrogen-Fixing Microsymbiont, Frankia , Thomas Andrew Permar Jan 1985

Soil Autecology Of The Nitrogen-Fixing Microsymbiont, Frankia , Thomas Andrew Permar

Retrospective Theses and Dissertations

The ability of the Frankia endophyte to infect its host plant may be markedly altered by changes in soil conditions. Plant bioassays showed lowering soil water potential caused significant declines in plant infection rates. Organic matter levels also influenced infection with soils containing zero and high levels of organic matter exhibiting the greatest root nodule formation. The highest infection rates of Frankia occurred at pH 6.0, although these levels were not significantly different within the range of the test. Addition of combined nitrogen to soils had a substantial positive effect on infection rates of Frankia endophyte;Presence of the ...


Variation In Growth, Nitrogen Fixation, And Assimilate Allocation Among Selected Alnus Glutinosa (L.) Gaertn. Clones , Gregory Alan Miller Jan 1983

Variation In Growth, Nitrogen Fixation, And Assimilate Allocation Among Selected Alnus Glutinosa (L.) Gaertn. Clones , Gregory Alan Miller

Retrospective Theses and Dissertations

The purpose of this study was to gain a better understanding of genetic variation in growth characteristics of Alnus glutinosa (L.) Gaertn. Clones were selected from the largest and smallest individuals in one 14 and one 16 year-old plantation. The 20 selected clones plus 7 other clones of interest were propagated by softwood cuttings. Gas exchange measurements, both respiration and nitrogenase activity, of intact shoots and roots were attempted. However, due to limitations of facilities and the large number of measurements required, gas exchange measurements were foregone in favor of more detailed analysis of dry weight distribution, nitrogen fixation, and ...


Effect Of Light Intensity On Growth, Photosynthesis And Nitrate Reductase In Hybrid Poplars , Festus Ejilayo Fasehun Jan 1975

Effect Of Light Intensity On Growth, Photosynthesis And Nitrate Reductase In Hybrid Poplars , Festus Ejilayo Fasehun

Retrospective Theses and Dissertations

No abstract provided.