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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The distribution and abundance of nematodes (especially the plant parasites) in the arid region of South Australia / by J.M. Nobbs

Nobbs, J. M. (Jacqueline Mary) January 1987 (has links)
Includes bibliography / ii, 84 leaves, [7] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Pathology, 1987
42

The effects of copper and zinc on seven species of Atriplex

Weinstein, Jeffrey Michael January 1980 (has links)
No description available.
43

Phytostabilization Potential of the Klondyke Mine Tailings Site and its Associated Microbial Community

Mendez, Monica Orozco January 2007 (has links)
Phytostabilization is an emerging technology for the remediation of mine tailings sites. In arid and semiarid environments, mine tailings disposal sites are a major source of environmental pollution as they are subject to eolian dispersion and water erosion. Mine tailings are acidic to neutral, high in metal content, and nutrient poor. Furthermore, these sites remain unvegetated even after decades of no additional mining activity. In arid and semiarid regions, climatic variables such as high winds, salinity, and drought exacerbate the problem. The Klondyke mine tailings site is a model site for studying plant establishment in mine tailings within semiarid regions. It was a lead and zinc ore- processing operation from 1948 to 1958 and is similar in physicochemical characteristics to other acidic pyritic mine tailings.In a greenhouse study, a native drought tolerant halophyte, Atriplex lentiformis (Torr.) S. Wats., was evaluated for its potential as a phytostabilization candidate in compost-amended tailings from the Klondyke site. Germination, plant growth, and metal uptake of A. lentiformis were examined, and the microbial community was monitored by enumeration of autotrophic iron- and sulfur-oxidizing bacteria as well as heterotrophic bacteria. Results demonstrated that with 10 to 15% compost addition, growth of A. lentiformis was not affected and shoot metal concentrations were generally not a concern for foraging animals. Furthermore, the heterotrophic bacterial community is severely stressed but recovers with compost addition and successful plant growth. Therefore, A. lentiformis is a good candidate for phytostabilization of mine tailings with compost amendments.Poor revegetation of mine tailings has been attributed to the microbial community involved in acidifying tailings; however, no thorough microbial studies have been conducted. The second study characterizes the bacterial community of the Klondyke site and compares it to an offsite control sample. Results demonstrate that the heterotrophic community is indicative of soil health as it has a positive relationship with pH, phylotype richness, and diversity. Also, the mine tailings contain an unexplored diversity of acidophiles that are important in maintaining acidity and thus, metal bioavailability. Therefore, the bacterial community in mine tailings should be monitored in phytostabilization studies to evaluate restoration.
44

Spatial variation in the population dynamics of Atriplex vesicaria under sheep grazing / by Leigh P. Hunt.

Hunt Leigh P. (Leigh Philip) January 1995 (has links)
Bibliography: leaves 159-176. / x, 176, [61] leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1995
45

Carcass and eating quality of sheep grazing saltbush based saline pasture systems

k.pearce@murdoch.edu.au, Kelly L Pearce January 2006 (has links)
Forage halophytes such as saltbush (Atriplex spp) are being widely used to revegetate Australian saline land and can also provide a medium quality fodder source. There is widespread anecdotal evidence that sheep grazing on saltbush are leaner, tastier and juicer. This thesis investigated the potential to produce a high quality carcass with improved eating quality from grazing sheep on saltbush on saline land. The first experimental chapter in this thesis details an animal house experiment investigating the carcass, eating and wool quality and physiological responses of sheep ingesting a 60:40 dried saltbush (Atriplex nummularia):barley grain (S+B), ration verses a 33:25:42 lupin grain:barley grain:oaten hay ration (Control, C) for 10 weeks prior to commercial slaughter (Chapter 4). Subsequently, two field experiments were conducted to examine the effects of grazing saltbush on saline land compared to dry senesced pasture on carcass and eating quality of lambs (Goomalling 2003) and hoggets (Wickepin 2004) (both chapter 6) for 14 weeks. Both chapters demonstrated that the ingestion of saltbush resulted in significantly less fat and in the 2 field experiments the ingestion of saltbush resulted in more lean on the carcass compared to sheep grazing a stubble/pasture (control) ration. These are positive findings for processors as costs of fat denudation are high so the lower the fat content and for farmers because less fat is deposited on the carcass per unit of liveweight gain. The decreased deposition of fat was attributed to the higher protein:energy ratio available for production, secondary compounds in saltbush and lower circulating insulin and higher growth hormone of the S+B fed sheep compared to the control fed sheep. Further work is needed to determine if these beneficial improvements in carcass composition can be achieved without compromising animal production. The long term grazing of saltbush did not result in commercially desirable hot carcass weights unless the sheep were supplemented with a high energy source such as barley. The low growth rates are attributed to a decreased availability of energy substrates, low feed intake and increased energy output of sheep fed high salt diets. The low energy intake of the S+B fed sheep also resulted in an a significantly lower percentage of unsaturated fat and unchanged levels of saturated fat in the fat depots compared to the C treatment. Consumer taste tests conducted on meat from experiments in both chapter 4 and 6 indicated no difference between the treatments for any of the eating quality traits assessed. This can be considered a positive result as sheep can be finished on saltbush without any detriment to eating quality. High vitamin E levels in the meat may have also prevented the development of rancid flavours and aroma. It can be speculated that saltbush does not impart beneficial flavour and aroma volatiles as previously thought; instead the high vitamin E levels inhibit off-flavour and aroma development compared to meat from sheep grazed on dry pasture. The long term ingestion of saltbush also resulted in significantly lower urine specific gravity (USG), muscle dry matter and higher urine weights suggesting that the saltbush fed sheep had a better hydration status compared to control fed sheep. However, this finding did not correspond with higher hot carcass weight or dressing percentages. The increases in muscle fluid content of the saltbush fed sheep were attributed to changes in body composition. The saltbush fed sheep had a higher lean and lower fat content which corresponded with a greater body fluid content as found in the animal house study. Under conditions where the body composition of sheep remains the same, the use of short term strategic feeding of components of saltbush was investigated (mimicked in the form of salt and betaine) to reduce dehydration and subsequent reductions in carcass weight and dressing percentages (Chapter 7). Salt and or betaine were fed for 1 week either prior to a 48 h period of water deprivation or prior to 48 h commercial slaughter process where water was available in lairage from 24-48 h. Under both scenarios the diets did not result in improved dressing percentages, hot carcass weights, muscle dry matter or muscle weights. The ingestion of high salt diet prior to slaughter, did increase fluid retention in the extracellular spaces prior to slaughter however by 48 h both groups were at a similar physiological and therefore similar hydration status. Therefore similar levels of fluid were present in the muscles and no difference in carcass weight or dressing percentage could be expected. An important observation from the second experiment was that the high salt group drunk more water than the low salt fed sheep but the low salt group consumed fluid in lairage also. The low salt fed sheep may have been encouraged to drink water after observing the frequent drinking patterns of the high salt group. This thesis has also shown that saltbush contains high levels of vitamin E (á-tocopherol) (193 mg/kg dry matter). As a result the concentration of á-tocopherol in plasma, liver and muscle of the saltbush fed sheep was elevated compared to those grazing dry pasture. The high muscle concentrations of vitamin E in the saltbush-grazed sheep resulted in improved meat colour stability. The high vitamin E levels did not influence the drip and cooking loss of the meat despite a decrease in the muscle dry matter of the meat. The browning of meat and increased drip loss results in large losses to the meat industry due to value deterioration at the supermarket. There is also great potential for the high vitamin E content in saltbush to be used for the prevention of nutritional myopathy instead of using expensive and labour intensive synthetic supplements. In conclusion, this thesis has provided an insight into the carcass and eating quality of sheep grazed on saltbush based saline pasture systems. The most significant findings were that
46

Nutritive value for goats of Atriplex species grown with hypersaline water

Wiley, Susan Taft. January 1982 (has links) (PDF)
Thesis (M.S. Animal Sciences)--University of Arizona, 1982. / Includes bibliographical references (leaves 38-41).
47

Effect of type and level of carbohydrate supplementation on intake and digestibility of Atriplex nummularia cv. De Kock by sheep

Du Toit, C. J. L. January 2006 (has links)
Thesis (M. Sc.(Agric.))( Animal Science)--University of Pretoria, 2006. / Includes bibliographical references. Available on the Internet via the World Wide Web.
48

Fitorremediação de um neossolo flúvico sódico salino de Pernambuco com Atriplex nummularia Lindl

SOUZA, Edivan Rodrigues de 26 April 2010 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2016-07-06T13:11:51Z No. of bitstreams: 1 Edivan Rodrigues de Souza (1).pdf: 935002 bytes, checksum: 814ab3406904eb74d9b9815203ca58d6 (MD5) / Made available in DSpace on 2016-07-06T13:11:51Z (GMT). No. of bitstreams: 1 Edivan Rodrigues de Souza (1).pdf: 935002 bytes, checksum: 814ab3406904eb74d9b9815203ca58d6 (MD5) Previous issue date: 2010-04-26 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Due to environmental and economic impacts of salinity and sodicity in soils, forms of recovery of theses soils contribute to improving the productivity and sustainability of farming systems and techniques for recovering theses soils is phytoremediation, using efficient plants at extracting of salts from soils. This study aims to evaluate the growth, production and extraction of salts by Atriplex nummularia grown on saline-sodic soil under water stress conditions, to compare soil properties before and after their cultivation, and to evaluate the osmotic potential of soil solution and morphoanatomy of vesicular cells accumulation of salts. The experiment was carried out in a greenhouse for 134 days, by growing Atriplex nummularia in pots with 20 kg of saline sodic with four levels of soil moisture (35, 55, 75 and 95% of field capacity) with a control (soil without plant). The experiment was performed in a randomized block with eight replications. The height, diameter and yield of dry leaf, stem and root were sensitive to soil moisture, and humidity corresponding to 75 and 95% of field capacity which resulted in better results. The vesicular cells of Atriplex nummularia were sensitive to variations in water content in soil. The variables of the exchangeable cations (Ca2+,Mg2+, K+, sum of bases) and total organic carbon remained stable between the beginning and end of the experiment in all treatments, while Na+ and exchangeable sodium percentage decreased after cultivation of the plant. In the soil solution the dynamics of the elements was evidenced by observing increases in Ca2+ Mg2+, Na+, Cl- and osmotic potential at the end of the cycle. The measurement of osmotic potential can be indicated as a good attribute for evaluating responses to treatments with hidric stress and saline water in plant and soil. The high concentrations of Ca2+, Mg2+, K+, and especially Na+ and Cl- in leaves of Atriplex nummularia, associated with high dry matter production characterizes this species as plant phytoextraction of salts. / Devido aos impactos ambientais e econômicos da salinidade e sodicidade em solos, formas de recuperação desses solos contribuem sobremaneira para a melhoria da produtividade e sustentabilidade dos sistemas agrícolas e uma das técnicas de recuperação destes solos é a fitorremediação, com a utilização de plantas eficientes na extração de sais dos solos. Este trabalho teve como objetivo avaliar o crescimento, a produção e extração de sais pela Atriplex nummularia Lindl. cultivada em solo salino sódico sob condições de estresse hídrico, comparar propriedades do solo antes e após seu cultivo, além de avaliar o potencial osmótico da solução do solo e das folhas e analisar a morfoanatomia das células vesiculares acumuladoras de sais. O experimento foi desenvolvido em casa de vegetação durante 134 dias, cultivando-se Atriplex nummularia em vasos com 20 kg de solo salino sódico em quatro níveis de umidade (35, 55, 75 e 95% da capacidade de campo), com um tratamento controle (sem cultivo), montados em blocos casualizados, com oito repetições. A altura, o diâmetro e as produções de massa seca de folha, caule e raiz foram sensíveis à umidade do solo, sendo as umidades correspondentes a 75 e 95% da capacidade de campo as que possibilitaram os melhores resultados. As células vesiculares de Atriplex nummularia foram sensíveis a variações do teor de água no solo. As variáveis do complexo sortivo do solo (Ca2+, Mg2+, K+, soma de bases) e o carbono orgânico total permaneceram estáveis entre o início e final do experimento em todos os tratamentos, enquanto o Na+ e a percentagem de sódio trocável diminuíram após o cultivo da planta. Na solução do solo a dinâmica dos elementos foi evidenciada, observando aumentos de Ca2+, Mg2+, Na+, Cl- e potencial osmótico ao final do ciclo. A medida de potencial osmótico pode ser indicada como um bom atributo para avaliar as respostas de tratamentos com estesse hídrico e água salina em planta e solo. As altas concentrações de Ca2+, Mg2+, K+ e, especialmente Na+ e Cl- nas folhas de Atriplex nummularia, associadas à elevada produção de massa seca caracteriza esta espécie como planta fitoextratora de sais.
49

Bactérias halotolerantes associadas a plantas de atriplex nummularia L. e sua inoculação em mudas

SILVA, Flaviana Gonçalves da 11 July 2014 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-12-14T18:24:04Z No. of bitstreams: 1 Flaviana Goncalves da Silva.pdf: 1354445 bytes, checksum: 5abe875dd282d6291759e442aef4933a (MD5) / Made available in DSpace on 2016-12-14T18:24:04Z (GMT). No. of bitstreams: 1 Flaviana Goncalves da Silva.pdf: 1354445 bytes, checksum: 5abe875dd282d6291759e442aef4933a (MD5) Previous issue date: 2014-07-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Salinity is a limiting factor for agriculture and a frequent problem in arid and semi-arid region which rainfall is low and poorly distributed. In these areas most of plants can not grow due soils unprotected and become degraded with time. The use of bacteria with plant growth promoting and tolerance to salt stress may indicate biotechnological alternative that allows the use of plants associated with these microorganisms as inoculants may provide beneficial effects on soil-plant interaction. The cultivation of Atriplex nummularia L. has been conducted in order revegetate soils, promoting the improvement of their physical and chemical properties as a phytoremediation technique of salinized soils. In order to isolate and select bacteria promoter of plant growth associated with Atriplex nummularia L. plants cultivated in two experiments were carried out in the Pernambuco state and evaluated the effects of its inoculation in Atriplex plants grown in greenhouse. The population density of the bacteria was determined and then the same were tested in respect to plant growth promotion in vitro solubilization of inorganic phosphate (SFI), biological nitrogen fixation (BNF), synthesis of indole acetic acid (IAA), exopolysaccharides production (EPS) and quorum sensing molecule. Some bacteria to plant inoculation Atriplex grown in a protected environment were also selected in order to analyses content of chlorophyll a, b and total; stomatal conductance (gs); leaf temperature; green matter, dry and total fractional parts (root, stem and leaf) of plants; content and levels of sodium, potassium, calcium and magnesium; total nitrogen, crude protein of leaves and total organic carbon. Through the insulation, it was obtained 107 halotolerant bacterial isolates with positive results to plant growth promotion. Regarding the content of chlorophyll a, b and total, stomatal conductance and crude protein in plants, there was no effect of treatments. Inoculation with halotolerant bacteria and plant growth promoters influenced total nitrogen and total organic carbon in plants of Atriplex. Therefore, there are halotolerant bacteria associated with Atriplex plants able to solubilize inorganic phosphate, N2 fixation, IAA production, EPS and quorum sensing molecule, with the possibility of these micro-organisms contribute positively to plant growth. Bacterial isolates are promising on vegetative and nutritional development of Atriplex. However, it requires further explore the effect of bacterial inoculants associated with halophytes, giving improved conditions for phytoremediation process of salinized soils. / A salinidade constitui um fator limitante à agricultura e tem se tornado um problema frequente em áreas sob clima árido e semiárido, onde as precipitações são reduzidas e mal distribuídas. Nessas áreas, a maioria das plantas não consegue se desenvolver, por isso, os solos ficam desprotegidos e tornam-se degradados com o tempo. A utilização de bactérias promotoras de crescimento vegetal com tolerância ao estresse salino pode indicar alternativa biotecnológica que possibilite o uso de plantas associadas a esses micro-organismos como inoculantes, podendo proporcionar efeitos benéficos na interação solo-planta. O cultivo da Atriplex nummularia L. tem sido realizado com o objetivo de revegetar estes solos, promovendo a melhoria de suas propriedades físicas e químicas, como técnica de fitorremediação de solos afetados por sais. Com isso, objetivou-se isolar e selecionar bactérias promotoras de crescimento vegetal associadas às plantas de Atriplex nummularia L. cultivadas em dois experimentos instalados no estado de Pernambuco e avaliar os efeitos da inoculação destas bactérias em plantas de Atriplex cultivadas em ambiente protegido. Foi determinada a densidade populacional das bactérias e em seguida as mesmas foram testadas quanto às características de promoção de crescimento vegetal in vitro: solubilização de fosfato inorgânico (SFI), fixação biológica de nitrogênio (FBN), síntese de ácido indol acético (AIA), produção de exopolissacarídeo (EPS) e molécula quorum sensing. Foram também selecionadas algumas bactérias para inoculação em plantas de Atriplex cultivadas em ambiente protegido, analisando-se nas plantas, aspectos como teor de clorofila a, b e total; condutância estomática (gs); temperatura foliar; fitomassa verde, seca e total das partes fracionadas (raiz, caule e folha) das plantas; conteúdos e teores de sódio, potássio, cálcio e magnésio; nitrogênio total, proteína bruta de folhas e carbono orgânico total. Por meio do isolamento, foi possível obter 107 isolados bacterianos halotolerantes, com resultados positivos quanto às características de promoção de crescimento vegetal. Em relação ao teor de clorofila a, b e total, condutância estomática e proteína bruta nas plantas, não houve efeito dos tratamentos aplicados. A inoculação com bactérias halotolerantes e promotoras de crescimento vegetal influenciou o nitrogênio total e carbono orgânico total em plantas de Atriplex. Portanto, é possível afirmar que existem bactérias halotolerantes associadas às plantas de Atriplex, capazes de solubilizar fosfato inorgânico; fixar N2; produzir AIA, EPS e molécula quorum sensing, havendo a possibilidade destes micro-organismos, quando associados às plantas, contribuírem de forma positiva em relação à promoção de crescimento vegetal. Os isolados bacterianos são promissores no desenvolvimento vegetativo e nutritivo da Atriplex. No entanto, necessita-se explorar melhor o efeito dos inoculantes bacterianos associados às plantas halófitas, dando condições para melhoria no processo de fitorremediação de solos salinos.
50

Avaliação nutricional e função renal de ovinos alimentados com feno de erva-sal (Atriplex nummularia L) e farelo de milho em substituição a palma forrageira (Opuntia Ficus-indica Mill)

ARAÚJO, Renaldo Fernandes Sales da Silva 17 February 2009 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-05-16T14:10:58Z No. of bitstreams: 1 Renaldo Fernandes Sales da Silva Araujo.pdf: 391694 bytes, checksum: 33d0d79be3abbae93ed9fd9f54acb1ad (MD5) / Made available in DSpace on 2017-05-16T14:10:58Z (GMT). No. of bitstreams: 1 Renaldo Fernandes Sales da Silva Araujo.pdf: 391694 bytes, checksum: 33d0d79be3abbae93ed9fd9f54acb1ad (MD5) Previous issue date: 2009-02-17 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Twenty sheep were used, adults, whole, without defined racial pattern, with medium alive weight of 19 kg. The animals were housed in individual stalls, provided of feeding, drinking fountain and saltcellar. The experimental period had 15 days for adaptation the facilities and evaluation of the physiologic conditions of the animals and 30 days for consumption evaluation, digestibility and renal function. The treatments consisted of the cacut substitution for atriplex hay and corn bran in the levels of hay of 0,0; 14,3; 30,5; 57,2 and 82,7%. The diets were offered twice a day (9:00 and 15:00 hours), in form of complete ration, being adjusted daily in function of the consumption of the previous day, allowing surpluses of 20%. During the collection period samples of the victuals were removed, of the water, of the surpluses, of the feces, of the urine and blood of the animals. The completely randomized design with five diets and four repetitions for treatment. The consumption of DM, NDF, CP and OM was influenced by the substitution of the cactus it forages for atriplex hay. There was not significant difference of weight earnings among the animals distributed in the experimental diets. The absorption and the retention of K depend on the concentrations of the Na in the diet. Diets composed exclusively of palm and soy needs a suplementação of In Na the.. Diets composed exclusively of cacut and soy needs a supplement of Na. Sheep fed by diets composed by cactus or atriplex as voluminous exclusive, he doesn't have difference in the urine production. / Foram utilizados vinte carneiros, adultos, inteiros, sem padrão racial definido, com peso vivo médio de 19 kg. Os animais foram alojados em baias individuais, providas de comedouro, bebedouro e saleiro. O período experimental teve 15 dias para adaptação as instalações e avaliação das condições fisiológicas dos animais e 30 dias para avaliação de consumo, digestibilidade e função renal. Os tratamentos consistiram da substituição de palma por feno de atriplex e farelo de milho (FAFM) nos níveis de feno de 0,0; 14,3; 30,5; 57,2 e 82,7%. As dietas foram oferecidas duas vezes ao dia (9:00 e 15:00 horas), em forma de ração completa, sendo ajustada diariamente em função do consumo do dia anterior, permitindo sobras de 20%. Durante o período de coleta foram retiradas amostras dos alimentos, da água, das sobras, das fezes, da urina e sangue dos animais. O delineamento experimental utilizado foi inteiramente casualizado, com cinco dietas e quatro repetições por tratamento. O consumo de matéria seca, fibra em detergente neutro, proteína bruta e matéria orgânica foram influenciados pela substituição da palma forrageia por feno de atriplex e farelo de milho. Não houve diferença significativa de ganho de peso entre os animais distribuídos na dietasexperimentais. A absorção e a retenção de K dependem das concentrações de Na na dieta. Dietas composta exclusivamente de palma e soja necessita de uma suplementação de Na. Ovinos alimentados com dietas compostas por palma ou atriplex como volumoso exclusivo não tem diferença na produção de urina.

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