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Articles 231331 - 231360 of 250135

Full-Text Articles in Life Sciences

An Analysis Of Stock Densities And Harvest Of The Cutthroat Trout Of The Snake River, Teton County, Wyoming, John W. Kiefling May 1972

An Analysis Of Stock Densities And Harvest Of The Cutthroat Trout Of The Snake River, Teton County, Wyoming, John W. Kiefling

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An intensive creel census and marking program was conducted in 1969 and 1970 to make possible population estimates and estimates of harvest of cutthroat trout in the Snake River in Teton County, Wyoming. Stock density determinations made in one of the five study areas provided an estimate of 400 and 992 cutthroat trout, eight inches or more in length, per mile of stream in 1969 and 1970 respectively.

Harvest data provide an estimate of 5,207 and 5,903 cutthroat trout harvested in 1969 and 1970 respectively. The harvest estimates obtained in this study are not comparable to those made in 1967 …


A Cytological, Morphological, And Anatomical Study Of Elymus Simplex, Stephan L. Hatch May 1972

A Cytological, Morphological, And Anatomical Study Of Elymus Simplex, Stephan L. Hatch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this paper is to clarify the taxonomy, report the chromosome number, report meiotic chromosome behavior, and give the anatomy of Elymus simplex Scribner and Williams. The isotype of Elymus simplex and the type description were used to compare this and other species that have been confused.

Cytological and anatomical methods are reported as an aid in clarification of the taxonomic problem that has been associated with this species.


Host-Parasite Relationship Studies Of The Larval Alfalfa Weevil And The Ichneumonid Parasite Bathyplectes Curculionis (Thomson), Yeboa A. Duodu May 1972

Host-Parasite Relationship Studies Of The Larval Alfalfa Weevil And The Ichneumonid Parasite Bathyplectes Curculionis (Thomson), Yeboa A. Duodu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The parasitic effects of the ichneumonid Bathyplectes curculionis (Thomson) on the larval alfalfa weevil, Hypera postica (Gyllenhal), were studied.

Results of experiments on the rates of parasitism of the four host larval instars indicated that the first three are either preferred by the parasite over the fourth instar larvae or are more susceptible to the parasite's attack. Survival of the younger weevil larvae after their exposure to female parasites was markedly poorer than that of unparasitized larvae. Premature death of host larvae was probably from both the puncturing by the parasite's ovipositor and the feeding and other activities of parasite …


Induction And Initial Characterization Of Male-Sterile Mutants On The Second Chromosome Of Drosophila Melanogaster, Susan M. Graves May 1972

Induction And Initial Characterization Of Male-Sterile Mutants On The Second Chromosome Of Drosophila Melanogaster, Susan M. Graves

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fourteen recessive, male-sterile, autosomal mutants of Drosophila melanogaster were induced using ethyl methanesulfonate. The techniques employed restricted the recovery of mutants to those located on the second chromosome. Eleven of the mutants were male-sterile at 23°C, and the remaining three, though fertile at 23°C, were male-sterile at 28°C. Complementation tests involving all possible pairs of mutations showed each to be located in a unique cistron.

Spermiogenesis in each mutant was studied by light microscopy to determine the stage at which cellular differentiation deviates from normal and to characterize the associated gross abnormalities. Phase contrast microscopy showed that each mutant sterile …


Endodontic Sealing Properties Of Cavit, Chloro-Rosin Gutta Percha, N2, And Silver Cones Using Radioisotopes, Frank H. Beal May 1972

Endodontic Sealing Properties Of Cavit, Chloro-Rosin Gutta Percha, N2, And Silver Cones Using Radioisotopes, Frank H. Beal

Loma Linda University Electronic Theses, Dissertations & Projects

The main purpose of this investigation was to test the endodontic sealing abilities of silver cones, N2, warm gutta percha, chemically softened gutta percha, laterally condensed gutta percha and Cavit under carefully controlled conditions. Evaluations were done by radiographic, macroscopic, microscopic, and autoradiographic examinations.

The four points which must be considered when evaluating the efficacy of sealing root canal systems, in vivo, were presented and discussed.

Cavit as a total endodontic filling material was presented, investigated and discussed.

An improvement of the chloro-rosin - gutta percha diffusion technique was presented.

The concept of surface as well as marginal leakage was …


Limitation Studies Of Seed Set In The Onion Allium Cepa L. (Liliaceae), Nizar Shukri Shasha'a May 1972

Limitation Studies Of Seed Set In The Onion Allium Cepa L. (Liliaceae), Nizar Shukri Shasha'a

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two field experiments were carried out. In the first experiment, 13 variables were studied for 3 inbred groups as influenced by genetic differences, source of pollen, soil moisture, fertilizers, and size of bulbs. Path-coefficient analysis was made of various insect pollinators influencing seed yield in different inbreds, and of components of seed production in all inbreds together. In the second experiment, 4 variables were studied for one male-sterile inbred and one male-fertile inbred as influenced by soil moisture and fertilizers.

Genetic differences among inbreds were the most important source of variation in seed yields. This points out that a major …


The Effect Of Hibernation On Memory In Spermophilus Lateralis, Mary Colleen Mcnamara May 1972

The Effect Of Hibernation On Memory In Spermophilus Lateralis, Mary Colleen Mcnamara

Biology ETDs

Spermophilus lateralis, were trained to solve a black-white discrimination task in order to escape from a water filled tank. Following the attainment of criterion, the ground squirrels were trained on the reversal task of the original discrimination problem. Twenty-four hours after reaching criterion on the reversal training, all subjects were placed in a hibernaculum at 7-10 C for a period of 11 days. The animals were returned to the laboratory after the 11-day

cold exposure period, and 24 hr later were tested for retention of the learned behavior. The animals were returned to the hibernaculum for an additional 11 days …


Assay And Control Of Staphylococcal Enterotoxin A Development In Cheddar Cheese Slurries, Niranjan R. Gandhi May 1972

Assay And Control Of Staphylococcal Enterotoxin A Development In Cheddar Cheese Slurries, Niranjan R. Gandhi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Attempts were made to adapt the microtiter hemagglutination inhibition assay technique for the assay of enterotoxin A. The presence of a potent hemagglutinin in crude and partially purified preparations and the instability of sensitized erythrocytes prevented its use for routine analysis of enterotoxin from culture media and foods.

A capillary tube immunological assay was developed in which 1 μ g of enterotoxin/ml was detected in less than 1 hr . Interfacial reaction of antisera and enterotoxin solutions in a 1 mm internal diameter capillary tube allowed rapid detection and serological typing of enterotoxins.

Staphylococcus aureus growth and enterotoxin A development …


Early Life History Of The Mountain Whitefish Prosopium Williamsoni (Girard) In The Logan River, Utah, Lawrence Guy Brown May 1972

Early Life History Of The Mountain Whitefish Prosopium Williamsoni (Girard) In The Logan River, Utah, Lawrence Guy Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Growth and food habits of 399 Age 0 mountain whitefish from the Logan River, Utah, were studied between March, 1970, and April, 1971. At the end of their first six months of life, whitefish were 86-96 mm total length and weighed 6-8 grams (wet). Total temperature experience was 2,950-3,430 degree-days above 32° F. The length-weight relationship for Age 0 mountain whitefish was best described by three stanzas with slopes of 4.3333 for fish 12.5-17.0 mm total length, 3.4437 for fish 17.0-55.0 mm total length, and 2.8043 for fish 50.0-112.0 mm total length. Scalation commenced at 30-35 mm total length and …


The Influence Of Atmospheric Dust And Foliar Leachates On The Chemical Quality Of Throughfall In Northern Utah, Dennis R. Parent May 1972

The Influence Of Atmospheric Dust And Foliar Leachates On The Chemical Quality Of Throughfall In Northern Utah, Dennis R. Parent

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the summer of 1971 a research project was carried out in an attempt to determine the influence of dust and leachates on rainfall quality. Open precipitation collectors, collectors under polyethylene screens, collectors under Douglas-fir (Pseudotsuga menziesii) and juniper (Juniperus scopulorum), and leaf analyses were used to determine the relative effects of these two processes by which chemicals are incorporated into the rainwater. All samples were analyzed for sodium (Na+), calcium (Ca++), magnesium (Mg++), potassium (K+), and available phosphorus. Under the trees, sodium concentrations increased as much as …


Model For Estimating Soil Water Flow, Water Content, Evapotranspiration And Root Extraction, Musa N. Nimah May 1972

Model For Estimating Soil Water Flow, Water Content, Evapotranspiration And Root Extraction, Musa N. Nimah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A mathematical model was developed to predict water content profiles, evapotranspiration, water flow from or to the water table, root extraction and root water potential at the surface as functions of time under unsteady state conditions.

The model was tested in the field at The Hullinger Farm near Vernal, Utah, in 1970 and 1971. Comparison of water content-depth profiles show excellent agreement at the end of a 9- day run in 1970 on oats seeded to alfalfa. In 1971 with alfalfa as the crop, the data show best agreement, between predicted and computed water content-depth profiles, 48 hours after any …


Xenobiotic Detoxication Potential And Drug Induced Changes In Carbaryl Toxicity In The Alfalfa Leafcutter Bee, Megachile Rotundata (Febricius), Richard M. Lee May 1972

Xenobiotic Detoxication Potential And Drug Induced Changes In Carbaryl Toxicity In The Alfalfa Leafcutter Bee, Megachile Rotundata (Febricius), Richard M. Lee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The alfalfa leafcutter bee, Megachile rotundata, one of the most important pollinators of alfalfa, generally became more susceptible to carbaryl as the adults aged. LD50 values for carbaryl toxicity were 240,166, 109, and 51 μg carbaryl/gram for the 1, 2, 3, and 4 days-old adult male bees. For the female bees, these were 245 , 551, 289, and 262 μg car-baryl/ gram. Lipid content and microsomal enzyme activity (measured by EPN detoxication in vitro) decreased in both sexes as the bees aged.

Synergist ratios, defined as the ratio of the LD50 of carbaryl alone …


Inorganic Mercury Uptake And Mercury Tolerance Demonstrated By Several Species Of Algae, Daniel S. Filip May 1972

Inorganic Mercury Uptake And Mercury Tolerance Demonstrated By Several Species Of Algae, Daniel S. Filip

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The inhibition by low concentrations of inorganic mercury has been established for several species of freshwater algae, and a method has been developed to determine mercury levels in algal cells, having good precision at levels as low as one hundred parts per billion.

Rapid sorption of inorganic mercury by glassware was minimized by using heavy algal cultures and short term incubations. The rates and extent of mercury uptake by three species of freshwater green algae were delineated under laboratory conditions. Replicate mercury containing cultures yielded slightly different mercury concentrations upon analysis due to analytical errors and glass sorption. Therefore, percent …


Xanthium Strumarium L.: Extraction And Assay Of Floral Promotive Principles And Additional Investigations Into Inhibition Of Flowering, David D. Gibby May 1972

Xanthium Strumarium L.: Extraction And Assay Of Floral Promotive Principles And Additional Investigations Into Inhibition Of Flowering, David D. Gibby

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

New techniques in extraction and assay of florigenic substances were tested. Initial response to the buffer-PVP extracts proved promising, but after several successful experiments, results could not be duplicated. Possible reasons for the failure are discussed.

A long-day inhibitory effect, demonstrated earlier by Gibby and Salisbury (25), was further investigated. Experiments with 14C-labled assimilates disproved the hypothesis that the inhibition is a result of assimilate translocation. Other experiments pointed to the probability of phytochrome involvement as well as protein synthesis as part of the inhibitory process. The nature of inhibition was ascribed to a localized inhibitory condition, probably a …


Spermiogenesis In Two Male-Sterile Third-Chromosome Mutants Of Drosophila Melanogaster, Richard F. Wilkinson May 1972

Spermiogenesis In Two Male-Sterile Third-Chromosome Mutants Of Drosophila Melanogaster, Richard F. Wilkinson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An ultrastructural study of sperm differentiation was made on two male-sterile mutants of Drosophila melanogaster. The mutations were induced on the third chromosome with the monoalkylating agent ethyl methanesulfonate and were maintained in stock cultures over a balancer chromosome using a system of multiple inversions. The stages of sperm differentiation, a most dramatic form of cellular differentiation, were then studied at the electron microscope level to determine the effect of the mutations on sperm structure and to correlate those changes with normal sperm development.

Studies of the genetic control of cellular differentiation have been hampered by difficulties in devising …


The Effects Of Age And Induction On Cockroach Mixed Function Oxidase Activity And Cell Morphology, Richard L. Turnquist May 1972

The Effects Of Age And Induction On Cockroach Mixed Function Oxidase Activity And Cell Morphology, Richard L. Turnquist

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Female American cockroaches showed definite age-dependent changes in levels of activity of the microsomal mixed function oxidase chain. Cytochrome P-450 levels, EPN-detoxication, and p-nitroanisole O-demethylation activities were very low in young adult insects but increased steadily reaching a peak at about 100 days in fat body and at about 90 days in midgut and hindgut. The activities then declined rapidly reaching levels of young insects at about 130 to 140 days of age. NADPH-NT-reductase activity was high in young insects and declined during the first few weeks of adult life. This activity too showed a peak at about …


Population Ecology Of Uinta Ground Squirrels, Norman A. Slade May 1972

Population Ecology Of Uinta Ground Squirrels, Norman A. Slade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The behavior and ecology of Uinta ground squirrels (Spermophilus armatus) at the Utah State University Forestry Field Station northeast of Logan, Utah were studied from 1964-1971 to determine the role of behavior in population regulation. From 1965 to 1968, data were collected to establish population norms. In 1968, the population density was reduced experimentally to help elucidate regulatory processes. This paper compares the dynamics of the population before and after the population reduction.

Before the density reduction, juvenile survival was lower than that of yearlings and adults. The disappearance of juveniles was associated with their tendency to disperse …


The Effect Of Heat Treatment Of Fresh Frozen Vells On Rennin Extractability, Leesther Mifflin Holm May 1972

The Effect Of Heat Treatment Of Fresh Frozen Vells On Rennin Extractability, Leesther Mifflin Holm

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A procedure was developed for the extraction of rennet from fresh frozen vells. Frozen vells were minced in a Model VCM-25 Hobart Vertical Cutter/Mixer. Dry sodium chloride was added until the salt concentration in the moisture of the tissue was 10%. Salted tissue was placed in galvanized steel cells and heated in a water bath to 49, 54, 57 and 60 C for 0, 15, 30, 45 and 60 minutes. The heated tissue was dried to about 4% moisture at ambient temperature with the aid of an electric fan. The dried salted tissue was extracted with a sodium chloride solution …


Some Aspects Of Conditioning Behavior In Rainbow Trout, Salmo Gairdneri, Reed E. Harris May 1972

Some Aspects Of Conditioning Behavior In Rainbow Trout, Salmo Gairdneri, Reed E. Harris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Effects of exercise, social facilitation, and delayed conditioning after vi exercise on the learning behavior of 5 to 6-inch rainbow trout, Salmo gairdneri, was measured in a conditioned avoidance response apparatus. The conditioning schedule contained an intertrial interval between alternate presentations of conditioned (light) and unconditioned (shock) stimuli. This randomization eliminated learning losses found in a previous study. Mean percentage avoidance, the measurement of learning, did not decrease significantly during conditioning trials. Exercised fish learned avoidance better than did non-exercised fish. Mean percentage avoidance for fish exercised at 0.5 ft/sec was 66.3; at 1.0 ft/ sec, 1.5 ft/sec, and …


Tissue Mineral Imbalances In Cattle With Brisket Disease, Patricia H. Field May 1972

Tissue Mineral Imbalances In Cattle With Brisket Disease, Patricia H. Field

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Twenty four cattle, six each of healthy cows and calves, and cows and calves with brisket disease, were obtained, examined and slaughtered. The concentrations of calcium, chloride, cobalt, copper, iron, magnesium, molybdenum, phosphorus, potassium, sodium and zinc; and percent absolute dry matter and percent ash were determined in tissues selected from the following: cardiac, hepatic, renal, osseous, whole blood and blood serum. In addition, certain physical and biological parameters were recorded for each animal. The results were analyzed as a 2 x 2 factorial, segregating the effects of age and brisket disease, and the age-disease interaction.

The following statistically significant …


Plant Adaptation To Cold I. Chlorophyll Ii. Minerals, Peter Rosen May 1972

Plant Adaptation To Cold I. Chlorophyll Ii. Minerals, Peter Rosen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A number of montane herbs in northern Utah typically form flower buds beneath the snow cover and flower either through it or immediately after its recession. Two of these species, one naturally occurring, Claytonia lanceolata, and one cultivated bulb, Galanthus nivalis, were investigated for their response to this stress environment.

Snow depth patterns, chlorophyll content of tissues, and plants grown in light-tight boxes, suggest that light passing through the snow to reach plants growing underneath is not critically involved in the timing of their developmental cycles or in their ability to endure this low temperature environment.

Ability to endure stress …


Comparison Of Tensiometer And Climatological Methods For Estimating Soil Moisture Depletion And Scheduling Irrigation For Potatoes, Thayne B. Wiser May 1972

Comparison Of Tensiometer And Climatological Methods For Estimating Soil Moisture Depletion And Scheduling Irrigation For Potatoes, Thayne B. Wiser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis was to compare the tensiometer and climatic methods of scheduling irrigation of potatoes under field conditions. Tensiometers were placed in a 160 acre field to maintain the crop within the optimum moisture range and schedule irrigations. An automatic solid set system was used to apply water to the potato crop. Instrumentation was used to determine daily input for the climatological method. Daily evapotranspiration (Et) was computed and Et (tensiometer) was compared with Et (climatic). The results showed total variation of the climatic method from the tensiometer method of .62 inches or less than 5 per …


An Analysis Of Flock Organization In Black-Capped Chickadees, John Ivan Mosher May 1972

An Analysis Of Flock Organization In Black-Capped Chickadees, John Ivan Mosher

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An analysis was made of individual behavior and flock organization among 33 color-banded Black-capped Chickadees (Parus atricapillus) on a woodland tract in wester New York State, from December 1967 to June 1970. Also, three of these flocks were confined at various periods for an average aviary tenure of 26 days. From these observations I concluded that the hierarchy and interindividual relationship of a flock remain as observed in the field; testosterone propionate causes an increase in injected subordinate bird's activity; but did not effect a change in its rank.

From the observations in the aviary, it was found …


Low Temperature Germination Of Tomato Seeds, Dawn M. Gatherum May 1972

Low Temperature Germination Of Tomato Seeds, Dawn M. Gatherum

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to determine the pattern of inheritance of low temperature germination of tomato. This was accomplished by crossing a tomato (P.I. 341988) that germinates at a low temperature (10 C) with a commercial mechanical harvest cultivar (VF 145-B-7879). The parents, F1, F2, and F3 progenies were tested for low temperature germination responses at 10 C for 15 days. The results show that a single recessive gene is responsible for the low temperature germination character.

Also, a study of the seed coat thickness of the tomatoes VF 145-B-7879 and P.I. 341988 was …


Effects Of Several Solutes And Water Stress On Succinic Dehydrogenase Activity, Rex Alton Richards May 1972

Effects Of Several Solutes And Water Stress On Succinic Dehydrogenase Activity, Rex Alton Richards

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The influence of the concentration of several solutes on the activity of succinic dehydrogenases from acetone powders of several species was studied spectrophotometrically. The plants used were: Cauliflower (Brassica oleracea var. botrytis, L.) sugarbeet (Beta vugaris, L.) sunflower (Helianthus annus, L.), Halogeton glomeratus (M. Bieb) C.A. Mey., and Samphire (Salicornia rubra, A. Nels.). Sodium chloride, potassium chloride, mannitol, sucrose, glycerol, glucose, and Hoagland's solution, at increasing concentrations, were used.

Decreased (more negative) osmotic potential produced by sodium chloride, potassium chloride, and Hoagland's solution resulted in a slight increase in enzyme activity at low …


The Action Of Antibiotics And Antimetabolites On The Tobacco Mosaic Virus Infection Process In Bean Leaves, Virendra Nayyar May 1972

The Action Of Antibiotics And Antimetabolites On The Tobacco Mosaic Virus Infection Process In Bean Leaves, Virendra Nayyar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The action of 28 antibiotics and antimetabolites at varying concentrations was studied in coincidence with the bioassay of tobacco mosaic virus on detached bean leaves by using an ultrasonic method of inoculation developed by Lamborn, Cochran and Chidester.1 All tested chemicals were classified, in regard to the virus infection process, as inhibitory or stimulatory and their optimal concentrations in the inoculum were determined. Of the 28 antibiotics and antimetabolites studied, eight were found to stimulate while twenty inhibited TMV infection in bean leaves. From the results of these experiments, an attempt was made to characterize the nature of the …


Reproduction And Hematology Of The Cache Elk Herd, Thomas B. Follis May 1972

Reproduction And Hematology Of The Cache Elk Herd, Thomas B. Follis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The initial three years of a 10-year reproductive study of elk involved three major phases. A fourth was added because of convenience. Objective 1 was to ascertain pregnancy rates in yearling and mature elk by rectal palpation, associate these rates with subsequent fall cow/calf ratios, and to test concurrently an ultrasonic fetal heart detector. Rectally observed anatomical changes in gravid uteri of cattle were directly applicable to elk. Ultrasonic detections of pregnancies in elk and deer were unsuccessful.

Pregnancy rates in the 1969-70 winter of 100 and 0 percent, respectively, for 19 adult and five yearling elk were associated with …


Population Biology Of The Black-Tailed Jackrabbit (Lepus Californicus) In Northern Utah, L. Charles Stoddart May 1972

Population Biology Of The Black-Tailed Jackrabbit (Lepus Californicus) In Northern Utah, L. Charles Stoddart

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Population biology of the black-tailed jackrabbit population on a 250-square-mile area in Curlew Valley, northern Utah, was studied from 1962-70. During this period the fall population density index increased from 40.0 in 1962, to 60.6 in 1963, decreased progressively to a low of 21.2 in 1967, then increased the following 3 years to a high of 185.0 in 1970.

Breeding was synchronous with four conception periods each year; in some years a fifth conception period was evident. The first conception period occurred about the last half of January; other periods followed at 40-day intervals indicating a 40-day gestation period and …


Present Livestock Feed Balance, Projected Feed Requirement And Potential For The State Of Utah, Roberto Savelli C. May 1972

Present Livestock Feed Balance, Projected Feed Requirement And Potential For The State Of Utah, Roberto Savelli C.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objectives of this thesis were to estimate the present livestock feed balance and project livestock feed requirements and balances to 1980 for the State of Utah.

Present feed production was obtained from published data. Livestock feed requirements were calculated using factors published in Livestock-Feed Relationships, a publication of the United States Department of Agriculture.

The projections of feed requirements to 1980 were made by projecting livestock numbers based on a least squares analysis of past trends. Utilizing the projected numbers permits calculation of the feed requirements.

Feed production in 1980 was obtained by projecting past feed production and by …


Canopy Structure And Phenology Of Alpine Tundra Vegetation, Marcee Fareed May 1972

Canopy Structure And Phenology Of Alpine Tundra Vegetation, Marcee Fareed

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An inclined point frame was used to measure leaf area indices in an alpine tundra Kobresia stand and Deschampsia meadow on Niwot Ridge, Colorado. Measurements were made throughout the summer of 1971 at various heights in the canopy and for each species in the two communities. Maximum leaf area indices of 2.2 and 2.0 occurred in the Kobresia and Deschampsia sites, respectively. The Kobresia site was characterized by a single dominant species, Kobresia myosuroides, and a predominance of vegetation within 2.5 cm of mean ground level. The Deschampsia site had no single dominant species. The region of maximum foliage …