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Full-Text Articles in Life Sciences

Review Of The Wild Oat Inflorescence And Seed: Anatomy, Development And Morphology, M. V. S. Raju, David M. Sutherland Aug 1991

Review Of The Wild Oat Inflorescence And Seed: Anatomy, Development And Morphology, M. V. S. Raju, David M. Sutherland

Biology Faculty Publications

This slim volume describes a detailed study of the reproductive parts of Avena fatua, the wild oat plant-a common weed in the northern plains and the probable ancestor of the cultivated oat. The book integrates the author's own work with information from available literature and includes lengthy technical descriptions of the structure and the growth of the inflorescence, the floret, the ovule, the pollen grain, the embryo, the seed, and the young seedling. Throughout the work, the author relates the wild oat's structure and development to other grasses, other monocotyledons, and other seed plants, offering evolutionary interpretations of ...


Action Of Heptaminol Hydrochloride On Contractile Properties In Frog Isolated Twitch Muscle Fibre, Bruno Allard, Vincent Jacquemont, Fouad Lemtiri-Chlieh, Bernard Pourrias, Oger Rougier Jul 1991

Action Of Heptaminol Hydrochloride On Contractile Properties In Frog Isolated Twitch Muscle Fibre, Bruno Allard, Vincent Jacquemont, Fouad Lemtiri-Chlieh, Bernard Pourrias, Oger Rougier

fouad Lemtiri-Chlieh

1 Heptaminol stopped or delayed the progressive decline in tension which characterizes the phenomenon of fatigue in frog isolated twitch muscle fibre. 2 Heptaminol had no action on the sodium, potassium and calcium voltage-dependent ionic conductances. 3 The hypothesis of an action via an internal alkalinization was tested by comparison with the action of NH4Cl. Both substances increased the tension. 4 The action of hepataminol was suppressed in sodium-free (TRIS) solution or in the presence of amiloride while the action of NH4Cl was always observed. 5 These results could be explained by a stimulation of the Na/H antiport by ...


Primary Productivity And Species Composition Of A Reconstructed Wetland In Eastern Kentucky, Eric C. Webb May 1991

Primary Productivity And Species Composition Of A Reconstructed Wetland In Eastern Kentucky, Eric C. Webb

Morehead State Theses and Dissertations

A thesis presented to the faculty of the Department of Biological and Environmental Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Eric C. Webb on May 19, 1991.


Pesticide Transformation Products Research: A Future Perspective, L. Somasundaram, Joel R. Coats Mar 1991

Pesticide Transformation Products Research: A Future Perspective, L. Somasundaram, Joel R. Coats

Entomology Publications

Pesticide research has largely been restricted to the synthesis, effects, and fate of parent molecules. The identification of primary, secondary, and subsequently formed transformation products, and the toxicological evaluation of those products of potential environmental concern are crucial to create a much needed data-base on pesticide transformation products. The establishment of new regulatory policies will largely depend upon scientific information generated in the coming years.


Pesticide Degradation Mechanisms And Environmental Activation, Joel R. Coats Mar 1991

Pesticide Degradation Mechanisms And Environmental Activation, Joel R. Coats

Entomology Publications

Pesticides are degraded by many different mechanisms. Physical, chemical, and biological agents play significant roles in the transformation of insecticide, herbicide, and fungicide molecules to various degradation products. Transformation mechanisms include oxidation, hydrolysis, reduction, hydration, conjugation, isomerization, and cyclization. Resultant products are usually less bioactive than the parent psticide molecule, but numerous cases have been documented of metabolites with greater bioactivity. The physical and chemical properties of the degradation products are also different from those of the parent compound, and their fate and significance in the environment also are altered with the structural changes. The concept of "environmental activation" is ...


Interactions Between Pesticides And Their Major Degradation Products, L. Somasundaram, Joel R. Coats Mar 1991

Interactions Between Pesticides And Their Major Degradation Products, L. Somasundaram, Joel R. Coats

Entomology Publications

The interactions between parent pesticide compounds and their degradation product(s) can influence the fate of both pesticides and degradation products. The role of pesticide degradation products in influencing the persistence and degradation of parent compounds, and the enhanced degradation of degradation products are discussed. The significance of these interactions in crop protection is also addressed.


Pesticide Transformation Products In The Environment, L. Somasundaram, Joel R. Coats Mar 1991

Pesticide Transformation Products In The Environment, L. Somasundaram, Joel R. Coats

Entomology Publications

Pesticides applied in the environment are transformed by biological or nonbiological processes into one or more transformation products. For most pesticides, transformation results in detoxification to innocuous products. Major degradation products of some currently used pesticides, however, play an important role in pest control and environmental contamination. Some pesticide degradation products are of significance in crop protection by being effective against the target pests. Some can be responsible for inadequate pest control by inducing rapid degradation of their parent compounds. Degradation products as potential contaminants of environmental and food resources has been reported recently. Although most of the currently used ...


Preface Of Pesticide Transformation Products Fate And Significance In The Environment, L. Somasundaram, Joel R. Coats Mar 1991

Preface Of Pesticide Transformation Products Fate And Significance In The Environment, L. Somasundaram, Joel R. Coats

Entomology Publications

PESTICEDES HAVE BECOME an integral part of intensive agriculture. This has resulted in extensive research on the biological efficacy and environmental fate of pesticides. One area of significant interest is the transformation of pesticides in the environment. The mechanisms of pesticide degradation and the products formed from various physical, chemical and biological processes have been well documented. For most currently used pesticides, however, the fate and significance of their transformation products are yet to be elucidated.


Toxicity And Neurotoxic Effects Of Monoterpenoids: In Insects And Earthworms, Joel R. Coats, Laura L. Karr, Charles D. Drewes Jan 1991

Toxicity And Neurotoxic Effects Of Monoterpenoids: In Insects And Earthworms, Joel R. Coats, Laura L. Karr, Charles D. Drewes

Entomology Publications

The insecticidal activity of several monoterpenoids from essential oils was evaluated against insect pests. Toxicity tests illustrated the bioactivity of d-limonene, α-terpineol, β-myrcene, linalool, and pulegone against insects, including the house fly, the German cockroach, the rice weevil, and the western corn rootworm. Bioassays were conducted to assess their toxicity via topical application, fumigation, ingestion, and ovicidal exposures. Growth, reproduction and repellency were also evaluated in the German cockroach. Non-invasive electrophysiological recordings were used with an earthworm to investigate neurotoxic effects of the monoterpenoids. Relevant monoterpenoid bioassay results in the literature are also discussed.


Developmental Changes Of Seven Common Cultivars Of Green Peas (Pisum Sativum) , Yu-Hee Kim Jan 1991

Developmental Changes Of Seven Common Cultivars Of Green Peas (Pisum Sativum) , Yu-Hee Kim

Retrospective Theses and Dissertations

Biochemical changes occurring in developing green peas were studied in order to understand the textural and flavor changes. The activity of pectinmethylesterase (PME), a pectin modifying enzyme, was measured by the continuous spectrophotometric assay. Specific activity of PME decreased over all varieties and all sieve sizes as the seeds matured. Chelate soluble pectin contents were decreased or remained constant in all varieties. Decreased PME activity and pectin content indicated that the crosslinking of pectin and calcium might not play an important role in the firmness of green peas. The moisture level decreased as maturity increased, which was inversely related to ...


Photosynthetic Efficiency Of Drought-Induced Leaves In Neviusia Alabamensis, Jennifer Martsolf, Robert D. Wright Jan 1991

Photosynthetic Efficiency Of Drought-Induced Leaves In Neviusia Alabamensis, Jennifer Martsolf, Robert D. Wright

Journal of the Arkansas Academy of Science

Plants in one stand of Neviusia alabamensis Gray (Rosaceae), a rare shrub, became drought deciduous in July, 1990, and grew new leaves following rains in August. In September the photosynthetic efficiency of the new leaves was compared with that of old leaves in another stand of the same population. Although leaf area from regrowth was much less than old leaf area retained, photosynthetic efficiency in new leaves was about 3 times higher than in old leaves. This response is discussed in terms of compensation for drought-induced loss of leaves.


Survey And Annotated Checklist Of The Later Summer Flora Of The Moist Soil Units At Holla Bend National Wildlife Refuge, Stephen A. Walker, George P. Johnson Jan 1991

Survey And Annotated Checklist Of The Later Summer Flora Of The Moist Soil Units At Holla Bend National Wildlife Refuge, Stephen A. Walker, George P. Johnson

Journal of the Arkansas Academy of Science

We conducted a floristic survey of 22 moist soil units at Holla Bend National Wildlife Refuge during September and October of 1990. The moist soil units range in size from 0.4 to 9.7 ha and are depressions manipulated to provide food and shelter for waterfowl. In total, 60 taxa representing 24 families and 42 genera were identified and are compiled into an annotated checklist. The flora was dominated by the following families and genera in decreasing order of importance: Asteraceae (Xanthium), Polygonaceae (Polygonum), and Amaranthaceae (Amaranthus). The Poaceae and the Cyperaceae were well represented, but were of lesser ...


Mycorrhizal Fungi-Bradyrhizobium-Soybean Tripartite Symbiosis In Iowa Soils , Samina Khalil Jan 1991

Mycorrhizal Fungi-Bradyrhizobium-Soybean Tripartite Symbiosis In Iowa Soils , Samina Khalil

Retrospective Theses and Dissertations

Soybean [Glycine max (L.) Merr.] makes use of two important symbiotic microbial systems: the rhizobial system, in which Bradyrhizobium japonicum fix atmospheric N2 in root nodules, and the vesicular-arbuscular mycorrhizal system, in which VAM fungi increase uptake of phosphate and/or other nutrients from the soil or improve plant drought tolerance. Research has confirmed the advantage of bradyrhizobial and mycorrhizal associations in N and P deficient soils; however, these associations may be inhibitory, or have little effect on plant growth in well-fertilized soils. In Iowa over the past 30-40 years, farmers have been adding large quantities of fertilizers to get ...


Effect Of Weed Water Stress On Postemergence Herbicide Activity , Emilio Sabas Oyarzabal Jan 1991

Effect Of Weed Water Stress On Postemergence Herbicide Activity , Emilio Sabas Oyarzabal

Retrospective Theses and Dissertations

Shattercane (Sorghum bicolor (L.) Moench) and woolly cupgrass (Eriochloa villosa (Thunb.) Kunth) growing under water stress conditions suffer morphological and physiological changes that may affect the activity of postemergence herbicides. Morphological and physiological changes in shattercane and woolly cupgrass growing under different levels of water stress were determined. Leaf area expansion was the growth variable most affected in both species. Both plants exhibit decreased dry matter accumulation due to water stress treatments. Woolly cupgrass stomatal conductance was more affected by water stress than shattercane. Photosynthesis was greatly reduced in both weeds, but only partially related to decreased stomatal conductance, indicating ...


Relationships Between Ethylene Biosynthetic Pathway Metabolites During Banana Fruit Ripening , Sylvio Luis Honorio Jan 1991

Relationships Between Ethylene Biosynthetic Pathway Metabolites During Banana Fruit Ripening , Sylvio Luis Honorio

Retrospective Theses and Dissertations

An high-performance liquid chromatography (HPLC) procedure was developed for 1-aminocyclopropane-1-carboxylic acid (ACC) quantitation in banana fruit. This alternative method overcame difficulties encountered in previously published, nonHPLC procedures, and it is comparable to another HPLC procedure published recently. HPLC in a linear gradient mode yielded baseline separation of ACC from other amino acids. It was found that ACC content decreased concomitantly with an increase in ethylene (C[subscript]2H[subscript]4) production during the early stages of banana ripening. Conversely, a subsequent decrease in C[subscript]2H[subscript]4 production may have been caused by decreased ACC content or some unknown ...


Origin And Evolution Of Defective Interfering Rnas Of Tomato Bushy Stunt Virus, David A. Knorr, Thomas Jack Morris Jan 1991

Origin And Evolution Of Defective Interfering Rnas Of Tomato Bushy Stunt Virus, David A. Knorr, Thomas Jack Morris

Faculty Publications in the Biological Sciences

Viruses with defective genomes have been identified in association with virtually every major family of viruses and have been widely utilized as tools for investigating virus functions in animal cell culture systems (Perrault, 1981). It is generally thought that defective interfering viruses (DIs) arise through deletion, rearrangement, or recombination of a competent viral genome. DIs tack the ability for independent existence relying on their parental helper viruses to supply factors required for replication, maturation, and/or encapsidation (Huang and Baltimore, 1977). The interference attributed to DIs is thought to result from competition with the helper virus for factors required in ...


A Taxonomic Study Of Variation In Leptochloa Fascicularis (Lam.) Gray In The Central Great Plains, Todd A. Templeton Jan 1991

A Taxonomic Study Of Variation In Leptochloa Fascicularis (Lam.) Gray In The Central Great Plains, Todd A. Templeton

Biology Faculty Publications

The morphology of Leptochloa fascicularis (Lam.) Gray (Poaceae) was studied in 25 locations in eastern and central Nebraska to determine if this grass was separable into two distinct taxa as suggested in several recent sources. Field collections were supplemented with herbarium specimens from other parts of the Central Great Plains. Glume and lemma lengths, the characters used in published keys, provided no separations useful in dividing the material into two species or varieties. However, individual local populations exhibited significant differences from each other in these characters. Such local differences appear to be reasonable given the high degree of inbreeding that ...


New And Corrected Floristic Records For Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland Jan 1991

New And Corrected Floristic Records For Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland

Biology Faculty Publications

Nineteen species (including eight Eurasian ones) are newly recorded for Nebraska: Alopecurus arundinaceus, Amaranthus californicus, Asclepias asperula, A purpurascens, Cardamine {lexuosa*, Centaurea diffusa, Dipsacus laciniatus, Eriochloa villosa, Euclidium syriacum, Gentiana alba, Geranium viscosissimum, Geum vernum, Goodyera oblongifolia, Haplopappus multicaulis, Heterotheca latifolia, Lathyrus tuberosus, Polygonum douglasii, Scirpus saximontanus, Veronica biloba. Twenty-one others are shown to be more widespread in Nebraska than previously known, one has a more restricted range than previously reported, two (Scirpus smithii, S. torreyi) are deleted from the flora based upon corrected identifications, and the status of some rarely-collected species is updated. Thirty-two additions, two deletions, and two ...


Sterol Composition Of The Corn Root Lesion Nematode, Pratylenchus Agilis, And Corn Root Cultures, David J. Chitwood, William R. Lusby Jan 1991

Sterol Composition Of The Corn Root Lesion Nematode, Pratylenchus Agilis, And Corn Root Cultures, David J. Chitwood, William R. Lusby

Faculty Publications from the Harold W. Manter Laboratory of Parasitology

Sterols from mixed stages of the com root lesion nematode, Pratylenchus agilis, and uninfected corn root cultures were analyzed by gas chromatography-mass spectrometry. Twenty-eight sterols were identified in P. agilis, including nine not previously detected in nematodes. The major sterols were 24-ethylcholest-22-enol, 24-ethylcholesta-5,22-dienol, 24-methy1cholestanol, 24-ethylcholestanol, isofucostanol, and 24-ethylcholesterol. The principal corn root sterols were 24-ethylcholesta-5,22-dienol, 24-methylcholesterol, 24-ethylcholesterol, isofucosterol, and cycloartenol. Therefore, the major metabolic transformation of sterols by P. agilis was saturation of the sterol nucleus. In addition, very small amounts of 4α-methylsterols were biosynthesized by P. agilis. The 4-methylation pathway is unique to nematodes and was previously ...


Notes: Interpretive Analysis For Forage Yield Trial Data, Jeffrey F. Pedersen, K. J. Moore, Edzard Van Santen Jan 1991

Notes: Interpretive Analysis For Forage Yield Trial Data, Jeffrey F. Pedersen, K. J. Moore, Edzard Van Santen

Agronomy & Horticulture -- Faculty Publications

Forage cultivar evaluation is often done in small plots with multiple harvests throughout the growing season. Data is often summarized by presenting a yearly total yield for each cultivar in addition to the mean for each harvest date. Data summarization often becomes burdensome and difficult to interpret. Regressing yield against a growth index associated with harvest dates can be utilized to describe forage performance in a concise and easily interpreted format. Subsets of data from tall fescue (Festuca amndinacea Schreb.) yield trials conducted in Alabama and Kentucky were used to demonstrate the technique. The analysis involves regressing yield of a ...


Inheritance Of Acid-Soil Tolerance In Sorghum (Sorghum Bicolor) Grown On An Ultisol, C. I. Flores, L. M. Gourley, Jeffrey F. Pedersen, R. B. Clark Jan 1991

Inheritance Of Acid-Soil Tolerance In Sorghum (Sorghum Bicolor) Grown On An Ultisol, C. I. Flores, L. M. Gourley, Jeffrey F. Pedersen, R. B. Clark

Agronomy & Horticulture -- Faculty Publications

Inheritance of acid-soil tolerance (generally considered AI-toxicity tolerance) i.n sorghum [Sorghum bicolor (L.) Moench] is not clear. Forty F1 sorghum hybrids and their 14 parents were grown two seasons in the field at relatively high (67 and 71%) and low (43 and 42%) Al saturations on an acid Ultisol in Colombia, South America to evaluate the effects of acid soil on agronomic component traits and to better understand inheritance of acid-soil tolerance of sorghum. For plants grown at the high Al saturation levels, hybrids from acid-soil tolerant [AS-T] x acid soil-sensitive [AS-S] crosses were as tolerant as hybrids ...


Fertility And Forage Yield Of Sorghum X Sudangrass Hybrids In A1 And A3 Cytoplasm, J. J. Toy, Jeffrey F. Pedersen, K. J. Moore Jan 1991

Fertility And Forage Yield Of Sorghum X Sudangrass Hybrids In A1 And A3 Cytoplasm, J. J. Toy, Jeffrey F. Pedersen, K. J. Moore

Agronomy & Horticulture -- Faculty Publications

Most sorghum x sudangrass hybrids are currently produced in Al male-sterile cytoplasm. Availability of alternative cytoplasmic sterility systems allows production of sorghum x sudangrass hybrids that may have superior forage characteristics. A study was conducted to compare the agronomic performance of Al and A3 sorghum x sudangrass hybrids. A bulk of eight sudangrass populations was used to pollinate four grain sorghum inbreds normally used as females that had been sterilized in both Al and A3 cytoplasm, and two inbreds normally used as males that had been sterilized in A3 cytoplasm. The hybrids were evaluated in 1990. Results indicate that male-sterile ...


Nitrogen And Methyl Jasmonate Induction Of Soybean Vegetative Storage Protein Genes, Paul E. Staswick, Jing-Feng Huang, Yoon Rhee Jan 1991

Nitrogen And Methyl Jasmonate Induction Of Soybean Vegetative Storage Protein Genes, Paul E. Staswick, Jing-Feng Huang, Yoon Rhee

Agronomy & Horticulture -- Faculty Publications

Vegetative storage protein (VSP) and VSP mRNA levels in soybean (Glycine max) leaves correlated with the amount of NH4NO3 provided to nonnodulated plants. The mRNA level declined as leaves matured, but high levels of N delayed the decline. This is consistent with the proposed role for VSP in the temporary storage of N. Wounding, petiole girdling, and treatment with methyijasmonate (MeJA) increased VSP mRNA in leaves 24 hours after treatment. The magnitude of the response depended on leaf age and N availability. N deficiency essentially eliminated the response to wounding and petiole girdling. MeJA was almost as ...