No description available.

Salinity problems seriously affect agricultural production by reducing crop yield and arable land. The evaluation of potato genotypes (Solanum spp.) for their salinity (NaCl) tolerance in conventional field trials is time consuming and labour intensive. The results are often confounded by many field and environmental variations. In vitro bioassays can overcome some of these difficulties by providing faster, more convenient and dependable methods for screening and selection of salt tolerant potato genotypes. The objective of this research was to develop in vitro bioassay methods for screening and selection of salt tolerant potato. Under in vitro NaCl stress conditions, seed germination, early seedling growth, and single-node cutting bioassays were used to evaluate salinity tolerance. The selected genotypes were further tested with three in vitro bioassays (single-node cuttings, root tip segments, and microtuberization). The rankings of potato cultivar salinity tolerance were similar in these bioassays. The single-node cutting bioassay was recommended because it was simpler to perform than the root tip segment and microtuberization bioassays and did not exclude certain genotypes as did the microtuberization bioassay. The in vitro bioassay rankings were compared with yield ranking in field lysimeters. In both the in vitro and in vivo saline stress experiments, cvs. Kennebec and Russet Burbank were more salt tolerant than Norland. The tubers and microtubers harvested from previous experiments were tested in the greenhouse to investigate salinity carry-over effect for seed tuber production. There was no apparent residual carry-over effect found. Microtuber yield increase in the presence of low NaCl concentration was induced primarily by specific ion (Na+), and not osmotic effects. This research clearly indicated that in vitro bioassays are relatively simple, rapid, convenient, repeatable, and agree with the field lysimeter results. They can be used to substitute for f

Thesis (Ph.D.)--Ohio University, November, 2007. / Title from PDF t.p. Includes bibliographical references.

Thesis (Ph. D.)--Texas State University--San Marcos, 2009. / Vita. Includes bibliographic references (leaves 19-24, 46-50, 69-74, 97-101,127-131, 141-144). Also available on microfilm.

Thesis (M.S.)--Ohio University, March, 2010. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until October 1, 2010. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 63-65)

No description available.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2017-08-16T21:51:48Z No. of bitstreams: 1 VERS?O FINAL Sammya.pdf: 1907132 bytes, checksum: 1e1a59eb9dfae60b28627c832c9019fa (MD5) / Made available in DSpace on 2017-08-16T21:51:48Z (GMT). No. of bitstreams: 1 VERS?O FINAL Sammya.pdf: 1907132 bytes, checksum: 1e1a59eb9dfae60b28627c832c9019fa (MD5) Previous issue date: 2017-04-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The species Vatairea macrocarpa (Benth.) Ducke is typical of Brazil, popularly known as maleiteira, angelim-do-cerrado and bitter, and is popularly used to treat various pathologies. The present study had as objective to evaluate the chemical chemistry, a toxicity and biological potential of extracts of leaves and stem of V. macrocarpa. The extracts were obtained by maceration in methanol.The chemical composition was analyzed by Thin Layer Chromatography (TLC). Phenoliccompounds, flavonoid and antioxidant activity tests were performed using the diphenylpicrilhydrazyl radical sequestration method (DPPH) and the ?-carotene / linoleic acid co-oxidation method. The acute toxicity test and the motor coordination evaluation were performed by the rota-rod test, as well as the tests for the evaluation of the anti-inflammatory activity (carrageenan-induced paw edema) and analgesic (acetic acid, formalin and hot plate). In the extracts the presence of flavonoids, steroids, terpenes, coumarins, saponins and absence of alkaloids were identified. The content of phenolic compounds and flavonoids were determined and both extracts presented antioxidant activity in both methods. No toxic signs were observed for both extracts at the fixed dose of 300 mg / kg or changes in the motor coordination of the animals at the doses tested. Both the stem and the leaves showed antinociceptive and anti-inflammatory activity in the tests performed. In view of the promising results presented by this species it is necessary to continue the studies with the same in order to isolate and identify substances and elucidate their mechanisms of action regarding the anti-inflammatory and analgesic activities. / A esp?cie Vatairea macrocarpa (Benth.) Ducke ? t?pica do Brasil, conhecida popularmente como maleiteira, angelim-do-cerrado e amargoso, e ? utilizada popularmente para tratamento diversas patologias. O presente estudo teve como objetivo avaliar a composi??o qu?mica, a toxicidade e o potencial biol?gico dos extratos brutos das folhas e do caule de V. macrocarpa. Os extratos foram obtidos atrav?s da macera??o em metanol. A composi??o qu?mica foi analisadaatrav?s da Cromatografia em Camada Delgada (CCD) e testes de determina??o de fen?licos e flavonoides. A avalia??o da atividade antioxidante foi realizada atrav?s do m?todo de sequestro de radical difenilpicrilhidrazila (DPPH) e do m?todo de co-oxida??o do ?-caroteno/?cido linoleico. Testes in vivo de toxicidade aguda e a avalia??o da coordena??o motora pelo teste rota rod, al?mdos testes para a avalia??o da atividade anti-inflamat?ria (edema da pata induzida por carragenina) e analg?sica (?cido ac?tico, formalina e placa quente) foram realizados. Nos extratos foi identificada a presen?a de compostos fen?licos, esteroides, terpenos, cumarinas, saponinas e aus?ncia de alcaloides. Foi determinado o teor de compostos fen?licos e flavonoides e ambos os extratos apresentaram atividade antioxidante nos dois m?todos.N?o foi verificado sinais t?xicos por ambos os extratos na dose fixa de 300 mg/Kg, nem altera??es na coordena??o motora dos animais nas doses testadas.Tanto o caule quanto as folhas demonstraram atividade antinociceptiva e anti-inflamat?ria nos testes realizados. Diante dos resultados promissores apresentados por essa esp?cie deve-se continuar os estudos a fim de isolar e identificar subst?ncias, bem como elucidar seus mecanismos de a??o quanto ?s atividades anti-inflamat?ria e analg?sica.

The Russian wheat aphid, Diuraphis noxia is one of the most destructive exotic invaders of South Africa, capable of reducing individual wheat plant yields by up to 90%. Entomopathogenic fungi are important natural mortality factors associated with this aphid in its Eurasian endemic habitats as well as in the United States and Canada; their impact often exceeding that of predators and parasitoids. The principal objectives of this study included (1) baseline characterization of the aphid-pathogenic flora associated with aphids from South Africa, with special reference to six common cereal aphids, (2) quantification of the comparative impact of the different fungal species on the cereal-aphid complex in three different wheat producing regions of South Africa, (3) field evaluation of the Hyphomycete Beauveria bassiana against D. noxia on resistant wheat, (4) screening of six fungicides for their potential usage in managing entomophthoralean epizootics within greenhouse rearings of the Russian wheat aphid, and (5) development and evaluation of a novel bioassay protocol for screening entomopathogenic Hyphomycetes against D. noxia. A total of nine species of fungi known to infect and kill aphid hosts were collected, including the six entomophthoraleans, Pandora neoaphidis, Conidiobolus thromboides, Conidiobolus obscurus, Entomophthora planchoniana, Conidiobolus coronatus and Neozygites fresenii, and three Hyphomycetes, Beauveria bassiana, Verticillium lecanii, and Paecilomyces farinosus. The former four entomophthoraleans are considered first reports from this country. For the first time, morphological characteristics of these nine South African-collected species are visually depicted and techniques for their isolation and in vitro culture discussed. Seven species of fungi were recorded from D. noxia, of which P. neoaphidis was the most important, causing up to 50% mortality during the late season under dryland conditions in the summer-rainfall region. Mycoses at epizootic levels, together with the large diversity of fungal species recorded from this host, indicated a high level of susceptibility to fungal infection. In contrast, infection of the oat aphid Rhopalosiphum padi remained < 5% despite favourable numbers of hosts and apparently suitable environmental conditions. This phenomenon strongly suggests some level of low susceptibility to fungal infection in this species. Under irrigated conditions m KwaZulu-Natal, the rose-gram aphid Metopolophium dirhodum was the predominant aphid but remained below economical injury levels. Field surveys revealed that this aphid was effectively targeted by P. neoaphidis and C. obscurus, and findings suggest that in some areas of South Africa entomophthoralean fungi effectively suppress this aphid, negating the need for insecticide applications. On average, ca. 61% control of D. noxia on resistant wheat was observed following an application of B. bassiana (5 x 10¹³ conidia per hectare) during the early flag-leaf stage of the wheat. Efficacy of B. bassiana applications on younger plants appeared to be influenced by the level of aphid activity, possibly explained by secondary pick-up of inoculum by D. noxia. These findings accentuate the importance of understanding the tritrophic relationship between host plant, pest and pathogen. The fungicides copper oxychloride, mancozeb + oxadixyl, captab + metalaxyl, bittertanol, iprodione, and mancozeb at a rate of 0.1% active ingredient moderately to strongly inhibited C. thromboides vegetative growth (mean inhibition 81.1 %). Mancozeb at concentrations of 10.0, 2.0, 1.25, 0.5, 0.08, and 0.016% was further evaluated in vitro. The fungus growth cut-off point, midway between 1.25 and 2.0% mancozeb, was calculated and a rate of 1.625% active ingredient per litre of water was used to decontaminate the fungus-infected D. noxia cultures. A novel bioassay protocol was developed, employing live host plants for rearing aphids post inoculation. Using this design against D. noxia, an average LC₅₀ estimate of 85 conidia per mm² for B. bassiana strain GHA was calculated. Control mortality was restricted to levels below 4%. The data indicated high precision due to an average coefficient of variation for slope of less than 20%, and an average chi-squared value of 5.46 ± 2.74 (n = 10 assays). The design will accommodate the use of cereal aphid species other than D. noxia, while live host plants will facilitate tritrophic studies on the effect of host-plant resistance on fungus-induced mortality of D. noxia. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.