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McCoy, Mark Christopher. "The effects of phytohormones on growth and artemisinin production in hairy root cultures of artemisia annua l." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0529103-162012/.
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Feys, Bart Julienne Frans. "Towards positional cloning of COI1, an arabidopsis gene controlling the response to coronatine and methyl jasmonate." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317974.
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Zhang, Xunzhong. "Influence of Plant Growth Regulators on Turfgrass Growth, Antioxidant Status, and Drought Tolerance." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30739.
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A series of studies were conducted to examine the antioxidant status, drought and disease tolerance, and growth response to foliar application of soluble seaweed (Ascophyllum nodosum) extracts (SE) and humic acid (HA; 25% active HA or 2.9% active HA) in tall fescue (Festuca arundinacea Schreb), Kentucky bluegrass (Poa pratensis L.) and creeping bentgrass (Agrostis palusttis Huds.) grown under low (-0.5 MPa) and high (-0.03 MPa) soil moisture environments.
Foliar application of humic acid (2.9 % active HA) at 23.7 and 47.4 l/ha improved leaf water status, shoot and root development in tall fescue, Kentucky bluegrass and creeping bentgrass grown under drought. Humic acid (2.9% active HA) at 15.5 l/ha or SE at 326 g/ha significantly reduced dollarspot incidence and improved turf quality in creeping bentgrass.
Drought stress induced an increase of antioxidants alpha-tocopherol and ascorbic acid concentrations in the three turfgrass species. In the experiment with Kentucky bluegrass, drought stress increased beta-carotene concentration, but did not significantly influence superoxide dismutase (SOD) activity.
Foliar application of humic acid (25% active HA) at 5 l/ha and/or SE at 326 g/ha consistently enhanced alpha-tocopherol and ascorbic acid concentrations, leaf water status, and growth in the three cool-season turfgrass species grown under low and high soil moisture environments. In the experiment with Kentucky bluegrass, application of HA at 5 l/ha plus SE at 326 g/ha also increased beta-carotene content and SOD activity under low and high soil moisture environments. There were close positive correlations between the antioxidant status and shoot or root growth in the three turfgrass species regardless of soil moisture levels.
The antioxidant SOD activity, photosynthetic capacity in terms of Fvm690, and chlorophyll content in terms of Fm730/Fm690 exhibited a seasonal fluctuation in endophyte [Neotiphodium coenophialum (Morgan Jones and Gams) Glenn, Bacon, Price and Hanlin] -free and endophyte-infected tall fescue. Application of SE enhanced SOD activity, photosynthetic capacity, and chlorophyll content in tall fescue, especially at 4 weeks after SE treatment. The SOD activity, photosynthetic capacity and chlorophyll content were not significantly influenced by the endophyte infection. A close positive correlation between SOD and photosynthetic capacity during the summer was found in endophyte-free and endophyte-infected tall fescue.Ph. D.
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Santos, Valdinei Moreira dos. "Agrochemicals on growth and hormonal relations of \'Micro-Tom\' and Arabidopsis roots under water deficit conditions." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-06012017-171318/.
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The increasing concerns launched by debates about climate changes added to the uncontrolled growth of world population have opened a market to natural inputs for a more sustainable agriculture. Taking those concerns together, it is very important to think in advance in terms of finding solutions to increase the food production, with improved quality and in a supposed changing environment. Natural substances such as seaweed biostimulants are coming up as inputs for crops yield and abiotic stress tolerance enhancement with increasing use in agriculture. In this scene, it is important to understand effects and mode of action of these substances on plant physiology to permit the development of consistent products and guarantee the delivery of solutions to growers that assist them in solving their needs. Therefore, this research was carried out aiming to understand the role of agrochemicals (classical plant growth regulators and seaweed biostimulants) on root development and hormonal relations of tomato \'Micro-Tom\' and Arabidopsis under water deficit conditions. Ascophyllum nodosum extracts (ANE) ability to stimulate endogenous hormonal responses in conditions of drought and osmotic stress was tested. We carried out experiments with two plant models: one is classically used in plant science studies and the other, a crop-like plant model whose scientific findings can be applied for several crops. We used tomato hormonal mutants and reporter lines grown in conditions of drought stress to study the effects of plant growth regulators and seaweed extracts on root growth and hormonal responses, respectively. Additionally, we tested in vitro the effects of these substances on root growth of Arabidopsis seedlings under osmotic stress conditions. The root development of tomato and Arabidopsis was negatively affected by the presence of water deficit caused by drought and osmotic stress, respectively. Gibberellins biosynthesis inhibitors only affected the root growth of gibberellin-deficient mutant (gib-3). Extracts of the same seaweed presented different effects on root growth of Arabidopsis seedlings and hormonal responsiveness in roots of tomato, possibly due to variability in their compositions. ANE A and B show opposite effects on root growth. ANE A promotes root growth, whereas ANE B shows inhibitory effects. These substances seem to have little influence on auxin responses in roots, however, they alter the balance between abscisic acid and ethylene under drought conditions. The standardization of the composition of seaweed extracts complemented with studies on their physiological and molecular effects in crops is crucial for the establishment of these agricultural inputs as one of the solutions for current and future requirements of food production.As crescentes preocupações oriundas a partir dos atuais debates sobre mudanças climáticas somadas ao descontrolado crescimento da população mundial têm dado espaço para o uso de insumos agrícolas naturais, objetivando sustentabilidade na agricultura. Diante de tais preocupações, é importante pensar antecipadamente e encontrar maneiras de aumentar a produção e a qualidade de alimentos, em um ambiente de supostas mudanças climáticas. Substâncias naturais, como bioestimulantes à base de alga, estão ganhando relevância como melhoradores da produtividade e tolerância a estresses abióticos com crescentes usos na agricultura. Diante desse cenário, é importante compreender os efeitos e modos de ação dessas substâncias na fisiologia das plantas para permitir o desenvolvimento de produtos consistentes e garantir aos produtores soluções que atendam às suas necessidades. Portanto, este estudo foi realizado com o objetivo de entender o papel de agroquímicos (reguladores vegetais clássicos e biostimulantes à base da alga) sobre o desenvolvimento radicular e relações hormonais do tomateiro \'Micro-Tom\' e Arabidopsis sob condições de estresse hídrico. Foi testada a habilidade de extratos Ascophyllum nodosum (ANE) em estimular respostas hormonais em condições de seca e estresse osmótico. Foram realizados experimentos com duas plantas-modelo: Arabidopsis que é largamente utilizada em estudos científicos de plantas e o tomateiro \'Micro-Tom\', uma planta-modelo mais adequada para estudos aplicados à agricultura sob condições tropicais. Foram utilizados mutantes hormonais e linhas-repórter de tomate cultivadas em condições de seca para o estudo dos efeitos dos reguladores vegetias e extratos de alga no crescimento radicular e respostas hormonais, respectivamente. Além disso, foram testados in vitro os efeitos dessas substâncias no crescimento radicular de plântulas de Arabidopsis em condições de estresse osmótico. O desenvolvimento radicular do tomateiro e Arabidopsis foi negativamente afetado pela ocorrência do déficit hídrico causado por seca e estresse osmótico, respectivamente. Inibidores de giberelinas afetaram apenas o crescimento radicular do mutante com baixo nível endógeno giberelinas (gib-3). Extratos da mesma espécie de alga apresentaram diferentes efeitos no crescimento radicular de plântulas de Arabidopsis e resposta hormonal em raízes de tomateiro. ANE A e B aprensenta efeitos opostos no desenvolvimento de raízes. ANE A promove o crescimento radicular enquanto ANE A inibe. ANEs pouco influenciam as respostas auxínicas, contudo, essas substâncias alteram o balanço entre entre ácido abscísico e etileno sob condições de estresse hídrico por seca. A padronização da composição de extratos de alga somada aos estudos sobre os seus efeitos fisiológicos e moleculares em culturas é crucial para o estabelecimento desses insumos agrícolas como uma das soluções para as necessidades atuais e futuras da produção de alimentos.
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Binder, Bradley Fletcher. "The chemistry and biology of insect growth regulators from plants in the genus Nama (Hydrophyllaceae)." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184795.
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A strategy for the discovery of new insect growth regulators from arid lands plants was developed. Plant genera with a history of toxicity, medicinal use, or incorporation in native american cultures were selected. Forty-five species from twenty-one families were collected, extracted, and tested for biological activity on the large milkweed bug, Oncopeltus fasciatus. Eight extracts were toxic and the extract of Nama hispidum (Hydrophyllaceae) caused nymphs to undergo precocious metamorphosis to an adult. The active component of N. hispidum was precocene II (6,7-dimethoxy-2,2-dimethyl chromene). Nine Nama species, representing four of the five sections in the genus were gathered from Hawaii, California, Nevada, Arizona, New Mexico, and the Dominican Republic. In addition to the insect anti-hormone, precocene II (PII), present in N. hispidum, N. rothrockii contained at least two different insect juvenile hormone mimics, and N. sandwicense contained insect anti-hormone and insect juvenile hormone mimics. Fifth instar larvae of Heliothis zea were used as model insects to distinguish between post-ingestive intoxication and feeding deterrency during exposure to PII. Larvae fed artificial diet with PII were deterred from eating, and had retarded weight gain, growth, and development. Insects grown on diet with PII consumed less food, could not digest the food, or convert ingested food to body mass. in vivo radiotracer studies with the nutrient, ¹⁴C linoleic acid, show a lower rate of transport and incorporation of radioactivity into fat body tissue. A change in the midgut epithelial cells from PII resulted in reduced transport efficiency and retarded larval growth and development. Scanning electron microscopy of the midgut epithelia indicated that cytotoxic damage is induced by PII. Observed changes in the midgut epithelial cells are consistent with a destructive alkylation of cell structures by PII.
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Mendes, Luciane de Siqueira. "Efeitos de ethephon e giberelina no desenvolvimento inicial e em alguns parâmetros tecnológicos da cana-de-açúcar." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-11022011-090813/.
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A cana-de-açúcar é uma das principais e dos mais antigos cultivos do Brasil, ocupando lugar de destaque na economia do país devido à produção de açúcar e etanol. Atualmente, São Paulo é o principal estado produtor, impulsionando a economia brasileira devido as suas grandes áreas plantadas. O uso de reguladores vegetais vem se tornando uma prática rotineira, objetivando maximizar o potencial produtivo das culturas, promovendo melhorias na qualidade, otimizando os resultados agroindustriais e econômicos. Giberelina é um hormônio conhecido como promotor de crescimento e alongamento das plantas. O ethephon é um maturador vegetal muito utilizado na cultura da cana, promovendo a liberação de etileno quando em contato com o tecido vegetal. O objetivo do trabalho foi estudar a eficácia dos reguladores vegetais giberelina (GA) e ethephon (CEPA) aplicados em diferentes fases do desenvolvimento inicial, na morfologia e aspectos tecnológicos da cana-de-açúcar. Para isso foram efetuados quatro experimentos. As concentrações aplicadas de GA (0; 10; 25; 50 e 75 mg L-1) e CEPA (0; 225; 450; 900 e 1000 mg L-1), foram iguais nos dois primeiros experimentos. O primeiro experimento foi realizado no Horto Experimental do Departamento de Ciências Biológicas da ESALQ/USP, com a pulverização dos toletes, com dez repetições e o segundo foi realizado na Estação Experimental da Syngenta em Holambra com a pulverização de plantas jovens (na soqueira), com quatro repetições, sendo que os parâmetros biométricos foram avaliados quinzenalmente até aos 90 dias após o plantio (DAP). O terceiro experimento foi efetuado em casa de vegetação no Horto Experimental do Departamento de Ciências Biológicas da ESALQ/USP, sendo que para a avaliação dos parâmetros tecnológicos no início do desenvolvimento, pulverizaram-se toletes com GA 50 mg L-1 e CEPA 900 mg L-1 além do controle, utilizando-se de cinco repetições. As amostras foram coletadas e congeladas, para posteriores análises tecnológicas. No quarto experimento, avaliou-se a aplicação dos reguladores vegetais in vitro, onde se aplicou GA (0; 2,5; 5,0; 7,5 e 10 mg L-1) e CEPA (0; 25; 50; 100; 200 mg L-1), com 5 repetições. Os resultados foram submetidos a análise de variância pelo teste F, e comparados pelo teste de Tukey à 5% de probabilidade. No primeiro experimento, a aplicação de GA nos toletes reduziu de forma geral o desenvovimento inicial das plantas, enquanto os tratamentos com CEPA apresentaram resultados promissores ao desenvolvimento inicial, quando os parâmetros avaliados foram os perfilhos. No segundo experimento, a aplicação de GA em soqueira aumentou a altura da planta, sendo que CEPA retardou a altura das plantas e incrementou o número de perfilhos. No terceiro experimento, nas avaliações tecnológicas, GA e CEPA afetaram temporariamente os teores de açúcares totais produzidos nas folhas. No colmo, CEPA e GA afetaram de forma geral os parâmetros tecnológicos, reduzindo as atividades das invertases e os açúcares redutores e totais e No quarto experimento, a aplicação in vitro de GA, reduziu o número de perfilhos, enquanto aplicação de CEPA incrementou o número de perfilhos e reduziu a altura das plantas.Sugarcane is one of the major and oldest crops in Brazil, taking a prominent place in the economy because of the production of sugar and ethanol. Currently, Sao Paulo is the main producing state, boosting the Brazilian economy due to its large planted areas. The use of plant regulators has become a routine practice, aiming to maximize the yield potential of crops, improving quality, optimizing results for the agroindustry and economy. Gibberellin is a plant hormone known as a regulator of plant growth and elongation. Ethephon is a growth regulator widely used in maturing sugarcane cultivation, allowing the release of ethylene when in contact with the plant tissue. This work aimed to evaluate the effectiveness of plant regulators gibberellin (GA) and ethephon (CEPA), applied at different stages of early development, on the morphology and technological aspects of sugarcane. To that end, four experiments were performed. The concentrations of GA (0; 10; 25; 50 and 75 mg L-1) and CEPA (0; 225; 450; 900 and 1000 mg L-1), were equal in the first two experiments. The first experiment was conducted in the Experimental Garden of the Department of Biological Sciences, ESALQ / USP, by spraying of cuttings, with ten repetitions. The second was conducted at Syngenta\'s experimental station in Holambra, by spraying the young plants (at stumps) with four replicates, and biometric parameters were measured fortnightly until 90 days after planting (DAP). The third experiment was conducted in a greenhouse at the Experimental Garden of the Department of Biological Sciences, ESALQ / USP, and for the evaluation of technological parameters in early development, cuttings were sprayed with GA 50 mg L-1 and CEPA 900 mg L-1 besides the control, using five replicates. Samples were collected and frozen for later technological analysis. In the fourth experiment, the application of plant regulators in vitro was evaluated, where GA (0; 2.5; 5.0; 7.5 and 10 mg L-1) and CEPA (0; 25; 50; 100; 200 mg L-1) were applied with five replicates. The results were submitted to variance analysis by F test and compared by Tukey test at 5% probability. In the first experiment, the application of GA reduced, in general terms, the initial development of plants whereas treatments with CEPA had promising results in early development, regarding the tillering. In the second experiment, the application of GA increased plant height, while the CEPA retarded plant height and increased the number of tillers. In the third experiment in technological assessments, GA and CEPA temporarily affected the contents of total sugars in the leaves. In the stem, GA and CEPA affected, in general, technological parameters, reducing the activities of invertase as well as those of the reducing and total sugars. In the fourth experiment, the application of GA in vitro decreased the number of tillers, while the treatment with CEPA increased the number of tillers and delayed the plant height.
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Monteiro, Giselle Gomes. "Desenvolvimento de micorrizas arbusculares em mutantes hormonais de tomateiro (Lycopersicon esculentum cv Micro-Tom)." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-17032011-104351/.
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Os hormônios vegetais etileno e ABA são possíveis reguladores chave do desenvolvimento das micorrizas arbusculares (MAs). O primeiro objetivo deste trabalho foi avaliar o desenvolvimento da MA em mutantes superprodutores e insensíveis ao etileno (epinastic e Never ripe, respectivamente) e verificar se enzimas relacionadas ao sistema de defesa vegetal são reguladas diferencialmente pelo etileno durante o desenvolvimento da simbiose A colonização de raízes de epinastic (epi) por G. clarum foi significativamente reduzida quando comparada com Micro-Tom (MT), além disso, a funcionalidade da simbiose, demonstrada pelo acúmulo de transcritos de LePT4, foi fortemente reduzida quando comparada com MT. Por outro lado, o padrão de colonização e funcionalidade da simbiose no mutante Nr não diferiu de MT. Indução no acúmulo de transcritos de genes que codificam quitinases e enzimas relacionadas ao estresse oxidativo foi observada no mutante epi, enquanto o acúmulo de transcritos de uma -1,3-glucanase foi fortemente induzido no mutante Nr. O segundo objetivo foi verificar se a colonização reduzida observada em mutantes deficientes em ABA é dependente da produção do etileno. Para tanto, mutantes que diferem na deficiência de ABA e produzem diferentes quantidades de etileno (notabilis e sitiens) e o mutante epi foram inoculados com G. clarum e tratados com aminoethoxivinilglicina (AVG), um inibidor de etileno. A colonização intrarradicular de G. clarum nos mutantes epi e notabilis (not) foi significativamente reduzida quando comparada com MT, sendo que o mutante sitiens (sit) foi o menos susceptível à colonização em relação aos demais genótipos. A aplicação de AVG a 10 µM restaurou completamente a colonização em epi, mas não nos mutantes deficientes em ABA. O acúmulo de transcritos de LePT4 confirmou os resultados de colonização. Os genes que codificam enzimas chave na biossíntese do etileno, LeACS2 e LeACO4, foram regulados positivamente pela inoculação com G. clarum, e a restauração do desenvolvimento da MA observada em epi que recebeu AVG, provavelmente envolveu ACC oxidase (LeACO4). O acúmulo de transcritos dos genes que codificam ACC oxidase (LeACO1 e LeACO4) foi induzido significativamente em sit, mostrando que a superprodução de etileno observada neste mutante pode envolver a regulação da ACC oxidase. Por fim, indução no acúmulo de transcritos do gene LeNCED foi observada em todos os genótipos micorrizados e em raízes de epi que receberam AVG, demonstrando que LeNCED é regulado positivamente pela inoculação com G. clarum e que o etileno regula a expressão deste gene. Os resultados demonstram que etileno e ABA estão envolvidos na regulação do desenvolvimento de MA e que etileno modula a expressão de genes relacionados ao sistema de defesa vegetal permitindo o estabelecimento de uma simbiose funcional.The plant hormones ethylene and ABA are probably key developmental regulators of arbuscular mycorrhizae (AM). The first objective of this work was to evaluate the development of MA in overproducing and insensitive mutants to ethylene (epinastic and Never ripe, respectively) and verify if enzymes related to plant defense system are differentially regulated by ethylene during the symbiosis development. The colonization of epinastic (epi) roots by G. clarum was significantly reduced when compared with Micro-Tom (MT), moreover, the functionality of the symbiosis as demonstrated by transcripts accumulation of LePT4, was strongly reduced when compared with MT. Still, the pattern of colonization and functionality of the symbiosis in the Nr mutant did not differ from MT. Induction in the transcripts accumulation of genes encoding chitinase and enzymes related to oxidative stress was observed in epi mutant, whereas transcripts accumulation of -1, 3-glucanase was strongly induced in the Nr mutant. The second objective was to determine whether the reduced colonization observed in mutants deficient in ABA is dependent on ethylene production. For this purpose, mutants that differ in ABA deficiency and produce different amounts of ethylene (notabilis and sitiens) and the epi mutant were inoculated with G. clarum and treated with an ethylene inhibitor called aminoethoxivinilglicin (AVG). The intraradical colonization of G. clarum in epi and notabilis (not) mutants was significantly reduced when compared with MT and sitiens mutant was less susceptible to colonization in comparison with other genotypes. The application of AVG to 10 µM completely restored the colonization in the epi but not in mutants deficient in ABA. The transcripts accumulation of LePT4 confirmed the results of colonization. The genes that encode key enzymes in the biosynthesis of ethylene, LeACS2 and LeACO4, were positively regulated by inoculation with G. clarum and the restoration in the development of MA observed in epi which received AVG probably involved ACC oxidase (LeACO4). Transcripts accumulation of genes that encode ACC oxidase (LeACO1 and LeACO4) were induced significantly in sit showing that overproduction of ethylene in this mutant can involve ACC oxidase. Finally, the induction in the accumulation of gene transcripts LeNCED was observed in all genotypes and mycorrhizal roots of epi which received AVG demonstrating that LeNCED is regulated positively by the inoculation with G. clarum and that ethylene regulates the expression of this gene. Results show that ethylene and ABA are involved in regulating of MA development and ethylene modulates the expression of genes related to the plant defense system allowing the establishment and functionality of the symbiosis.
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Childerhouse, Emma. "The effect of a natural plant extract and synthetic plant growth regulators on growth, quality and endogenous hormones of Actinidia chinensis and Actinidia deliciosa fruit : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Horticultural Science at Massey University, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1052.
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Kiwifruit are of huge economic importance for New Zealand representing 29 percent of total horticultural exports. Fruit size is the biggest determinant of what consumers are willing to pay, and there is also a positive relationship between consumer preference for flavour and percentage dry matter. The two main cultivars exported from New Zealand are Actinidia chinensis ‘Hort 16A’ (gold kiwifruit) and A. deliciosa ‘Hayward’ (green kiwifruit). Under current commercial practice the only product allowed for use on kiwifruit to increase fruit size in New Zealand is Benefit®. Benefit® has been shown to induce different results when applied to A. chinensis and A. deliciosa, whereas synthetic plant growth regulators such as the cytokinin-like substance N-(2- chloro-4-pyridyl)-N’-phenylurea (CPPU) have been found to promote similar increases in fresh weight of fruit in both cultivars. Final fruit size is determined by both cell division and cell enlargement. It was been shown that fresh weight can be increased in both of the major Actinidia cultivars even though their physiology differs. Hormonal control of fruit size in relation to cell division and cell enlargement phases of fruit growth was studied in both A. chinensis and A. deliciosa. CPPU was applied to both cultivars in a growth response experiment where fruit were collected throughout the growing season. The objective of this experiment was to create growth curves, to compare and contrast the effect on A. chinensis and A. deliciosa, and to provide material for hormone analysis. Application of CPPU was found to significantly increase the fresh weight of both A. chinensis and A. deliciosa fruit (46.98 and 31.34 g increases respectively), and alter the ratio of inner and outer pericarps of A. chinensis fruit. CPPU and Benefit® were applied individually and together to both cultivars. It was found that only A. chinesis fruit were affected by the application of Benefit®; fresh weight was increased by 26.38 g, and percentage dry matter was significantly reduced. There was a statistically significant (p < 0.05) interaction between CPPU and Benefit® when applied to A. chinensis. 3,5,6-trichloro-2-pyridyloxyacetic acid (3,5,6-TPA) was applied to A. deliciosa on two application dates at three concentrations and was found to decrease fresh weight of fruit, but significantly increase percentage dry matter regardless of application date or concentration. Lastly CPPU and 1-naphthalene acetic acid (NAA) were applied to A. deliciosa at two application dates and in all combinations. Application date affected the response to both a low concentration of CPPU and NAA. A synergistic interaction was observed when CPPU was applied early plus NAA late (CPPU early (4.53 g increase) plus NAA late (13.29 g) < CPPU early plus NAA late (33.85 g). Finally endogenous hormone content was studied. Methods were developed and tested for the simultaneous analysis of both indole-3-acetic acid (IAA) and cytokinins. Freeze dried fruit were purified using Waters Sep-pak® cartridges and Oasis® columns then IAA was quantified by high pressure liquid chromatography. Preliminary results indicate a correlation between application of CPPU and endogenous IAA, high concentrations of IAA correlated well with periods of rapid fruit growth particularly for CPPU treated fruit.
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Westerlund, Stephanie. "Measuring juvenile hormone and ecdysteroid titers in insect haemolymph simultaneously by LC-MS the basis for determining the effectiveness of plant-derived alkaloids as insect growth regulators /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972100164.
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Dall'Orto, Luigi Tancredi Campo. "Auxinas e tipos de estacas no enraizamento de Camellia sinensis." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-21092011-104432/.
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Com o objetivo de avaliar a influência de cultivares, tipos de estacas de Camellia sinensis e doses de ácido indolbutírico no enraizamento de estacas, dois experimentos foram conduzidos em casa de vegetação, no delineamento experimental em blocos ao acaso com 16 tratamentos, no esquema fatorial 2 x 2 x 4, ou seja, tipos de estaca (herbácea e lenhosa), cultivares (Camellia sinensis IAC 259 e Yabukita) e quatro doses de ácido indolbutírico (AIB) (0, 30, 60 e 90 mg L-1), com quatro repetições. Cada repetição foi composta por 20 estacas da porção mediana dos ramos das plantas matrizes, coletadas em duas épocas do ano (verão e inverno). As estacas foram cortadas em bisel e mantidas com uma gema e uma folha inteira, com 5 a 7 cm de comprimento. A região basal das estacas recebeu ou não tratamento com ácido indolbutírico (AIB), através da imersão de 2,5 cm da base em solução aquosa do produto por 24 horas. Posteriormente, elas foram colocadas em bandejas de isopor de 72 células contendo vermiculita de grânulos médios. As estacas herbáceas apresentaram maior porcentagem de enraizamento com a aplicação de AIB comparada às estacas lenhosas, sendo que as estacas coletadas no período do verão apresentaram maior porcentagem de enraizamento em menor espaço de tempo, quando comparadas com as estacas coletadas no período do inverno. Estacas da cultivar Yabukita apresentaram maior potencial de enraizamento em relação às estacas da cultivar IAC 259. As concentrações recomendadas de AIB para o enraizamento de estacas de Camellia sinensis variaram de 56 a 83 mg L-1 em função da cultivar.Aiming to evaluate the influence of Camellia sinensis cultivars, types of cuttings and doses of IBA on rooting, two experiments have been conducted in a green house in the experimental design in blocks randomized with 16 treatments, arranged in a 2 x 2 x 4, that is, cutting types (herbaceous and woody), cultivars (Camellia sinensis \'IAC 259\' and \'Yabukita\') and four doses of butyric acid (IBA) (0, 30, 60 and 90 mg L -1) with four replications. Each replication consisted of 20 cuttings from the middle portion of the branches from the mother plants, collected in two seasons (summer and winter). The cuttings were cut in bevel and maintained with a bud and a leaf, with 5-7 cm long. The basal cuttings have received or not treatment with indol butyric acid (IBA) by immersion of 2.5 cm from the base in an aqueous solution of the product for 24 hours. Later, they have been placed in trays with 72 cells containing medium granules of vermiculite. Herbaceous cuttings have presented higher percentages of rooting with IBA application compared to hardwood cuttings, and cuttings collected in summer have showed the highest percentage of rooting in the shortest time compared with the cuttings collected in winter. Yabukita cultivars cuttings had higher rooting potential in relation to the IAC 259 cuttings. IBA level to the rooting of Camellia sinensis varied from 56 to 83 mg L-1 according to cultivars
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Baynham, Mark Kevin. "Gibberellin plant growth hormones." Thesis, University of Sussex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328329.
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Lima, Luara Cistina de. "Bioestimulante e fertilizantes foliares no cultivo de Brachiaria híbrida." Universidade Federal de Uberlândia, 2016. https://repositorio.ufu.br/handle/123456789/17854.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorBioestimulantes proporcionam incrementos no desenvolvimento vegetal quando aplicados isolados ou em associação com outros produtos. Todavia poucos estudos abordam aspectos vegetativos e produtivos relacionados à aplicação desses em gramíneas forrageiras. Diante disso, o presente trabalho teve como objetivo o estudo das respostas de gramíneas submetidas à aplicação de Bioestimulantes e fertilização foliar. Instalou-se dois experimentos individuais, utilizando a Brachiaria híbrida Convert HD364, na Fazenda Capim Branco, pertencente à Universidade Federal de Uberlândia. O primeiro experimento foi conduzido em delineamento em blocos casualizados, com seis tratamentos e quatro repetições. Os tratamentos foram doses de bioestimulantes (0,25; 0,5; 0,75; 1,00 e 1,25 L ha-1 em cada aplicação) e a testemunha que constou-se da ausência de aplicação do Bioestimulante. O segundo experimento foi conduzido em delineamento inteiramente casualizados, com 7 tratamentos e 3 repetições. Os tratamentos utilizados foram: testemunha (ausência de adubação), aplicação de 30 Kg ha-1 de N (ureia); 30 Kg ha-1 de N (ureia) + 3,0 L ha-1 de Mastermins® Pastagem; 30 Kg ha-1 de N (ureia) + 3,0 L ha-1 de Starter®; 30 Kg ha-1 de N (ureia) + 0,5 L ha-1 de Bioestimulante; 30 Kg ha-1 de N (ureia) + 3,0 L ha-1 de Mastermins® Pastagem + 0,5 L ha-1 de Bioestimulante; 30 Kg ha-1 de N (ureia) + 3,0 L ha-1 de Starter® + 0,5 L ha-1 de Bioestimulante, aplicados em cada ciclo, após o corte. Para os dois experimentos utilizou-se os tratos culturais recomendados para a Brachiaria híbrida Convert. As avaliações realizadas foram: produção de forragem, valor nutritivo (PB, FDN e FDA), massa de raízes e análise foliar para teores de nutrientes. Realizou-se o teste de Regressão para o primeiro experimento e o teste de Tukey a 0,05 de significância para o segundo experimento. Para o primeiro experimento, concluiu que o bioestimulante promove aumento no acúmulo de MS e na taxa de acúmulo de forragem, folhas e colmos de Brachiaria híbrida, redução no percentual de material morto e na relação de F:C Brachiaria híbrida e não interfere nos teores de N, K, P, Ca, Mg, S, B, Cu, Fe, Mn e Zn, o acúmulo de K, P, Ca, Mg, S, B, Cu, Fe, Mn e Zn, o acúmulo de MS e a taxa de acúmulo de material morto, a densidade de raízes, e percentual de folha e as concentrações de FDA, FDN e PB de Brachiaria híbrida Convert HD364, a partir dos resultados encontrados recomenda-se a dose de 1,25 L ha-1 de bioestimulante para Brachiaria híbrida Convert HD364 e para o segundo experimento, concluiu que Starter N® associado ao bioestimulante e ureia promove maior acúmulo de MS de forragem. Starter N® associado a ureia, Mastermins Pastagens® associado a ureia e bioestimulante e Starter N® associado a ureia e ao bioestimulante promovem aumentos no acúmulo de MS de folhas e de colmos. Starter® associado a ureia, Mastermins Pastagens® associado a ureia, Mastermins Pastagens® associado a ureia e ao bioestimulante e Starter® associado a ureia e ao bioestimulante promove aumento no acúmulo de MS de material morto. Mastermins Pastagens® associado a ureia e ao bioestimulante e Starter® associado a ureia e ao bioestimulante promove aumento na taxa de acúmulo de folha. Starter® associado a ureia, Mastermins Pastagens® associado a ureia e ao bioestimulante e Starter® associado a ureia e ao bioestimulante promove aumento taxa de acúmulo de colmo.
Bioestimulants provide increments in plant development when applied alone or in combination with other products. However, few studies address aspects vegetative and productive, related to the application of these in forage grasses. In addition, the objective of this work was to study the responses of grasses, submitted the application of bioestimulants and fertilization. It was installed two experiments, using the Brachiaria hybrid Convert HD364, on the Capim Branco Farm, belonging to the Federal University of Uberlândia. The first experiment was conducted in randomized blocks with six treatments and four replications. The treatments were doses of biostimulation (0.25; 0.5; 0.75; 1.00 and 1.25 L ha-1 in each application) and the witness who appeared to be the lack of application of bioestimulant. The second experiment was conducted in a completely randomized block design, with seven treatments and three replications. The treatments were: control (absence of fertilization), application of 30 kg ha-1 N (urea); 30 kg ha-1 N (urea) + 3.0 L ha-1 of Mastermins® Pasture; 30 kg ha-1 N (urea) + 3.0 L ha-1 of Starter®; 30 kg ha-1 N (urea) + 0.5 L ha-1 bioestimulant; 30 kg ha-1 N (urea) + 3.0 L ha-1 of Mastermins® Pasture + 0.5 L ha-1 bioestimulant; 30 kg ha-1 N (urea) + 3.0 L ha-1 of Starter® + 0.5 L ha-1 of bioestimulant, applied in each cycle, after the cut. The evaluations were forage production, nutritive value (CP, NDF and ADF), and root mass and leaf analysis for nutrient content. There was a regression testing for the first experiment and the Tukey test at 0.05 significance for the second experiment. For the first experiment, concluded that the bioestimulant promotes an increase in the accumulation of MS and the rate of accumulation of grass, leaves and stems of Brachiaria hybrid, a reduction in the percentage of dead material and in relation to F:C Brachiaria hybrid and does not interfere in the contents of N, K, P, Ca, Mg, S, B, Cu, Fe, Mn and Zn, the accumulation of K, P, Ca, Mg, S, B, Cu, Fe, Mn and Zn, the accumulation of MS and the rate of accumulation of dead material, the density of roots, and percentage of leaf and the concentrations of ADF, NDF and PB, from the results it is recommended that the dose of 1.25 L ha-1 bioestimulant for Brachiaria hybrid, Convert HD364. For the second experiment, concluded that Starter N® associated with the bioestimulant and urea promotes greater accumulation of MS of forage. Starter N® associated with urea, Mastermins Pastureland® associated with urea and biostimulating and Starter N® associated with urea and the bioestimulant promote increases in accumulation of MS from leaves and stems. Starter® associated with urea, Mastermins Pastureland® associated with urea, Mastermins Pastureland® associated with urea and the bioestimulant and Starter® associated with urea and the bioestimulant promotes an increase in the accumulation of MS of dead material. Mastermins Pastureland® associated with urea and the bioestimulant and Starter® associated with urea and the bioestimulant promotes an increase in the rate of accumulation of leaf. Starter® associated with urea, Mastermins Pastureland® associated with urea and the bioestimulant and Starter® associated with urea and the bioestimulant promotes increased rate of accumulation of stalk rot.
Dissertação (Mestrado)
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Oliver, J. F. "The effects of plant growth regulators and plant parasitic nematodes on cereal root growth." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233539.
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Johnson, Robert Jean. "Plant growth regulators : an alternative to frequent mowing /." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA232051.
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Thesis (M.S. in Management)--Naval Postgraduate School, June 1990.Thesis Advisor(s): Carrick, Pual M. "June 1990." Description based on signature page. DTIC Identifier(s): Plant growth regulators, growth indicators. Author(s) subject terms: Plant growth regulators, growth indicators. Includes bibliographical references (p. 39-40). Also available online.
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Soomro, M. H. "The effects of plant parasitic nematodes and plant growth regulators on root growth of graminacious plants." Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378682.
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Christensen, Cynthia Lehua Warnock. "The effect of plant growth regulators on the growth of Closterium moniliferum." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/3968.
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Physiologic responses to Gibberellic Acid (GA), I-Naphthalene Acetic Acid (NAA), Benzylaminopurine (BAP), and Abscisic Acid (ABA). suggest that Oosterium monilfferum has the ability to utilize these plant growth factors. The growth promoters NAA and GA both increased growth when added to the media. The cell division regulator BAP (a synthetic cytokinin). also had a promotive effect on growth. Abscisic acid was found to be inhibitive to growth.
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Norton, E. R., L. J. Clark, H. Borrego, and Bryan Ellsworth. "Evaluation of Two Plant Growth Regulators from LT Biosysn." College of Agriculture, University of Arizona (Tucson, AZ), 2005. http://hdl.handle.net/10150/198160.
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A single field study was conducted during the 2004 cotton growing season at the University of Arizona Safford Agricultural Center to evaluate the effect of two plant growth regulators (PGRs) manufactured by LT Biosyn Inc. on the growth, development, yield, and fiber quality of cotton grown in the southeastern region of the state. This test was designed as a follow up study to work that was performed in 2003 on a grower cooperator site that demonstrated positive lint yield responses to the use of one of the PGRs used in this project. This was an eight treatment test involving the application of two PGRs, HappyGroTM (HG) and MegaGroTM (MG). The two formulations are intended to have different effects on plant growth and development. The HG formulation is a kinetin based product designed to enhance cell division and differentiation. The MG formulation is designed to enhance root growth early in the season. Several treatment combinations were designed to investigate varying scenarios of application of these two products alone and in conjunction with each other. The test included a control and each treatment was replicated four times in a randomized complete block design. Plant measurements were collected throughout the season to look for differences in plant growth and development. Lint yield was estimated by harvesting the entire plot and weighing the seedcotton with a weigh wagon equipped with load cells. Sub samples were collected for fiber quality and percent lint determinations. Plant measurements revealed extremely high fruit retention levels throughout the entire season with end of season levels near 75%. This high fruit retention resulted in very low vigor. Under these conditions, while lint yield was extremely high for this region (1300-1600 lbs. lint per acre), no statistical differences were observed among treatments. Fiber quality measurements also revealed no significant differences.
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Temple-Smith, Kay Elizabeth. "The mode of action of novel plant growth regulators." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317880.
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Fuentes, Hector D., of Western Sydney Hawkesbury University, of Science Technology and Environment College, and of Science Food and Horticulture School. "Studies in the use of plant growth regulators on phytoremediation." THESIS_CSTE_SFH_Fuentes_H.xml, 2001. http://handle.uws.edu.au:8081/1959.7/112.
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Phytoremediation is a relatively new technology that uses plants for the clean up of contaminated soils.Its low cost, simplicity and environmentally friendly approach make this technology a viable option for remediation but the main drawback is that it must be considered as long term alternative given its slow speed. This work is the first to report the use of Plant Growth Regulators(PGR)to enhance the performance of phytoremediation so that less time is needed for remediation.Soil samples were taken from a heavy metal contaminated, abandoned mine site for plant growth trials. A clean soil was also analysed and used for reference.Trials were carried out by growing corn in the contaminated soils and using various concentrations of IBA and NAA together with soil amedments to see if these could increase the accumulation of Zn, Mn, Cu, Bb and Fe in corn. Several further tests were conducted and results noted.Doctor of Philosophy (PhD)
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Fuentes, Hector David. "Studies in the use of plant growth regulators on phytoremediation /." View thesis View thesis, 2001. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030505.150607/index.html.
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Thesis (Ph.D.) -- University of Western Sydney, Macarthur, 2001.A thesis presented to the University of Western Sydney, in partial fulfillment of the requirements for the degree of Doctor of Philosophy, December, 2001. Bibliography : leaves 163-173.
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Tickes, B., and M. J. Ottman. "Evaluation of Plant Growth Regulators on Wheat in Arizona, 1987." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/200841.
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Plant growth regulators are applied to small grains to decrease lodging which can adversely affect crop growth and yield. Wheat is intensively managed in Arizona, and lodging can be a problem. Chlormequat and ethephon were applied at various rates and times in six studies in 1987 to evaluate their use on Arizona's semi -dwarf cultivars with respect to lodging plant height, yield components and grain yield The results indicated that growth regulators applied at the recommended rates and times may decrease plant height and decrease kernel weight. However, the influence of growth regulator treatments on tiller number, head number, kernel number, and grain yield was not demonstrated. The ambiguous results obtained suggest our efforts need to be directed toward documenting the extent of lodging in the state, studying the effects of lodging and predicting when lodging will occur.
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Attaha, Ali H. Mohamad. "Effects of some plant growth regulators on productivity of strawberries." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252892.
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Helps, I. M. "The synthesis of plant growth regulators via alkyne hexacarbonyldicobalt complexes." Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381126.
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Magnitskiy, Stanislav V. "Controlling seedling height by treating seeds with plant growth regulators." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1101741472.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xix, 157 p.; also includes graphics. Includes bibliographical references (p. 147-157).
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Augustyn-Gradkowska, E. "Stereocontrolled synthesis of plant growth regulators, abscisic acid and xanthoxin." Thesis, London Metropolitan University, 1985. http://repository.londonmet.ac.uk/3314/.
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The project is concerned with the total synthesis of plant growth regulators related to abscisic acid (ABA). The biological activity of these plant growth regulators, ABA and Xanthoxin, and their derivatives is influenced by the stereochemistry of the double bond system in the side chain, the 2Z,4E-isomers being most potent.
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Sheridan, Norman P. "The interaction of plant growth regulators with cell membrane constituents." Thesis, Kingston University, 1986. http://eprints.kingston.ac.uk/20346/.
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The thesis describes the interaction of auxins with membrane fractions prepared from etiolated epicotyl tissue of ‘Pisum Sativum’ seedling. The interaction of auxins with phospholipids was also examined. Two classes of high affinity binding tissue sites were found in the growing region of the epicotyl tissue. Kinetic analysis of the data resulted in dissociation constant values of: K[sub]1=2.2x 10[sup]-7 M, n[sub]1=1.8x10[sup]-10 moles/g fresh wt; K[sub]2=11x10[sup]-7M, n[sub]2=3x10[sup]-10 moles/g fresh wt. These sites were not found in the non-growing region of the pea epicotyl suggesting that they may be involved in the growth process. From the competition studies reported here, it would appear that site 2 showed greater auxin specificity than site 1 and this could be considered a candidate as an auxin receptor. Sucrose gradient fractionation techniques were employed to further separate the two binding sites and it was shown that site 2 binding was associated with fractions rich in plasma membrane while site 1 was associated with the endoplasmic reticulum. Separation of the solubilized sites by gel permeation methods indicated an apparent molecular weight of 42,000 daltons. IAA was shown to complex with the polar head group region of phospholipids, in CDCl[sub]3, although the strength of the complex was rather low (Kd=1.9x10[sup]-2 Molal). The strength of binding was influenced by the polar head groups of the phospholipids, but did not appear to be affected by the fatty acyl chain length. The physiological significances of such interactions are discussed.
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Weir, A. J. "#alpha#-ketogutarate dependent gibberellin hydroxylases and plant growth regultion." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233760.
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Yuan, Kun Wysocka-Diller Joanna Singh Narendra K. "Functional and genetic analysis of plant transcription factors involved in the plant growth under various environmental conditions." Auburn, Ala, 2008. http://repo.lib.auburn.edu/2007%20Fall%20Dissertations/Yuan_Kun_37.pdf.
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Wright, Glenn C. "Use of Plant Growth Regulators for Improving Lemon Fruit Size - 2005." College of Agriculture, University of Arizona (Tucson, AZ), 2005. http://hdl.handle.net/10150/198104.
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Lemons were treated with several plant growth regulators for the 2005-06 season, with the hope of improving fruit size. These PGR’s included CropSet, Accel, Maxim, Messenger and MT350. Although there were some increases in yield, these were just trends, and were not statistically significant. Similarly, there was no improvement in fruit size with application of the treatment
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Bariola, Louis A. "Using Plant Growth Regulators to Control Pink Bollworms and Boll Weevils." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219781.
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Wright, Glenn C. "Use of Plant Growth Regulators for Improving Lemon Fruit Size - 2006." College of Agriculture, University of Arizona (Tucson, AZ), 2007. http://hdl.handle.net/10150/223662.
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Lemons were treated with several plant growth regulators for the 2006-07 season, with the hope of improving fruit size. These PGR’s included Bluestim, Accel, Maxim and MT1350. Although there were some increases in yield, these were just trends, and were not statistically significant. Similarly, there was no improvement in fruit size with application of the treatments.
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Dhansay, Mohamed Afzal. "Synthesis and metal binding properties of selected organophosphorus plant growth regulators." Thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/23201.
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Puglisi, Sadie Erica. "Use of Plant Growth Regulators to Increase Branching of Clematis Spp." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35000.
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Clematis spp. L. is a twining vine covered in showy blooms. Typical growth of hybrids is from the main leader, producing a thin, unbranched plant with one cyme. Apical dominance is released by cutting back the vine during production. Cutting back, or pinching, of a plant is labor intensive and compromises bloom for vegetative growth at time of sales. The purpose of this project was to eliminate manual pinching by treating young plants with chemical plant growth regulators (PGRs) that enhance branching without removal of the apical meristem. The first project evaluated the use of Atrimmec (dikegulac sodium), Fascination (BA+GA4+7), Florel (ethephon), and Dropp 50 (thidiazuron) on Clematis cultivars Ernest Markham, and Hagley Hybrid, and Clematis viticella 'Polish Spirit.' Plants treated with 800 mg·L-1 Atrimmec, or 800 or 1200 mg·L-1 Fascination experienced an increase in branch numbers. The second experiment manipulated the ratio of the components of Fascination, 6-BA and GA4+7, to reduce phytotoxicity experienced in the first experiment. The optimal ratio to enhance branching was 1:1, which is the stock solution for Fascination. All ratios produced phytotoxic symptoms. A third experiment tested lower rates of thidiazuron and added CPPU (forchlorfenuron) to the list of PGRs to test. The last experiment took the most effective PGR treatments, Atrimmec at 800 mg·L-1, and Fascination at 800 or 1200 mg·L-1, and compared them to the current production practices of pinching. Large flowering cultivars of clematis were used, including 'Comotesse de Bouchard,' 'Ernest Markham,' and 'Hagley Hybrid.' Atrimmec increased branch numbers and suppressed leader lengths without a mechanical pinch. Results from Fascination varied by cultivar.Master of Science
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Nasim, Muhammad. "Response of rice plants to plant growth regulators under saline conditions." Thesis, University of Aberdeen, 2003. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU164162.
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Responses of rice to plant growth regulators on germination and seedling growth under NaCl salinity were studied to identify possible means of increasing salinity tolerance. Gibberellic acid (GA) promoted germination processes and a-amylase activity and increased plumule but reduced radicle growth after emergence. GA partitioned more metabolites towards the plumule than the radicle. Chlormequat (CCC) showed no beneficial effects and abscisic acid (ABA) inhibited germination under saline conditions. Overall there was no large difference in the performance of three rice varieties, BR29, IR8 and Pokkali in germination. Artificially aged seeds showed increased sensitivity to salinity and GA produced similar effects on germination of artificially aged rice seeds as on unaged seeds. Seed pre-treatment with GA was as effective in promoting germination under saline conditions as applying GA in the germination media. GA with low Ca promoted germination and plumule growth as well as radicle growth. GA increased plant height and fresh weight of seedlings under saline conditions, however it did not show a large positive effect on rice seedlings. CCC had no beneficial effects on rice seedlings. ABA showed possible beneficial effects on rice seedlings as it reduced Na+ uptake and increased K+ and Ca2+ uptake. GA in combination with ABA appeared to adapt rice plants better to saline conditions. GA in combination with low Ca also promoted rice growth under saline conditions.
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Zhang, Yun-Heng. "Biochemistry and molecular biology of binding proteins for plant growth regulators." Thesis, De Montfort University, 2000. http://hdl.handle.net/2086/13254.
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Plant growth regulators have a vital role in plant growth and development. The cellular response to these regulators depends on the presence and the action of specific receptors. The plant growth regulators and their receptors act together in complexes which determine the final effects of the plant growth regulators. In the research reported here, emphasis has been given to the regulation of the activity of the receptors themselves. The regulation of the N-l-naphthylphthalamic acid (N~A) receptor through phosphorylation and dephosphorylation and the regulation of the auxin binding protein (ABP) through gene manipulation have been investigated. NPA, an auxin transport inhibitor, was found to bind specifically to a crude membrane preparation from sugar beet seedling leaf cell suspension cultures. The in vitro binding was optimal at pH 4.5 and 4?C. Binding parameters for NP A binding were determined by Scatchard analysis. The dissociation constant (Kd) and binding protein concentration were found to be 1.71 x 10-7 mol dm-3 and 220 pmoles g-I membrane protein respectively. It was found that the amount of specific 3H-NPA binding was significantly increased by adding Mg2+ A TP to the binding assay solution; treatment of membrane preparations with acid phosphatase, prior to the NP A binding assay, resulted in lower specific binding. A TP activation and phosphatase inactivation were culture stage dependent. Although a considerable effect could be detected when using cells from day 8 (representing the linear phase), the same treatment did not alter the binding if cells from day I (representing lag phase) or day 14 (representing the stationary phase) were used. These observations have strongly highlighted the possible involvement of a phosphorylation and dephosphorylation mechanism in vivo in the regulation of the activity of the NP A receptor. High phosphatase activity was found in the supernatant, but not in the membrane pellet, after 50,000 g centrifugation. The presence of a membrane-bound auxin receptor, ABP, was demonstrated by Scatchard analysis in sugar beet seedlings. The Kd value and the receptor concentration were found to be 2.15 x 10-6 mol dm-3 and 68 pmoles g-I membrane protein. The protein could be solubilised either with the detergent Triton X-I 00 or by acetone-washing, with a recovery of about 40%. An acetone-solubilised ABP preparation could be partially purified by DEAE-Sephacel ion exchange chromatography, NAA-linked AH-Sepharose 4B affmity chromatography or Sephadex G-200 gel filtration. The recovery after any of these chromatographic treatments was very low so that successive chromatography for further purification was unsuccessful. The low level of detectable binding after purification resulted mainly from the low abundance of ABP in the plant material. Non-radioactive labelling and detection techniques were used to show that an ABP-probe hybridized to sugar beet genomic DNA during dot blotting. The present study has indicated that receptor activity could be regulated by a phosphorylation and dephosphorylation mechanism in plants. The investigation has also suggested that the effect of plant growth regulators on plant development could be regulated through the manipulation of the expression of their receptor genes.
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Hood, L. R. "Multiple Plant Growth Regulator Use on Short Staple Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1993. http://hdl.handle.net/10150/209534.
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A field trial was initiated during the 1992 growing season to evaluate the activity of Cytokin and Piz applied alone or in combination to short staple cotton. The Cytokin treatment significantly increased lint yield over the other treatments. There were no statistically significant differences between the non-treated check and any other treatment. The Cytokin treatment increased lint yield an average of 81 pounds over the check plots. Fruit retention remained high throughout the season, indicating that Pix would not normally have been needed.
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Hood, L. R. "Multiple Plant Growth Regulator Use on Short Staple Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/210271.
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A field trial was conducted during the 1992 & 1993 growing seasons to evaluate the activity of Cytokin and Pic applied alone or in combination to short staple cotton. The Cytokin treatment significantly increased tint yield over the other treatments in 1992. There were no statistically significant seed cotton differences between the non - treated check and any treatment in 1993. Fruit retention remained high throughout 1992 and very high throughout the 1993 season. Under high fruiting conditions, use of a plant growth regulator would not normally be recommended.
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Tunio, Shamsuddin. "Effect on environment and plant growth regulators on the growth of different wheat genotypes." Thesis, Bangor University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293125.
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Alghamdi, Mohammed A. M. "Plant growth regulators effects on vegative growth, yield and yield components in winter wheat." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553077.
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Three glasshouse experiments and one field experiment were carried out to investigate the effect of the plant growth regulator on vegetative growth and yield components of reduced height isogenic lines of the wheat (Triticum aestivum L.) cultivar Mercia. The first experiment compared the growth regulator response of seven isogenic lines of Mercia. Subsequent experiments used four lines, (Mercia control, Rhtl Rht2, and Rht8). Two glasshouse experiments examined the responses under well watered and water stress conditions. The third glasshouse experiment examined rates and time of application under well watered conditions, whilst the field experiment had different rates of application. In all experiments growth regulators reduced plant height significantly in all lines. Growth regulator decreased total dry matter and grain yield with greatest reduction generally for the control and Rht8 lines. Rhtl was the least affected. There were few significant effects of growth regulator on gas exchange and chlorophyll fluorescence but the trend was for greater values with growth regulator. In the first glasshouse experiment, a rate of 2.0 1 ha-1 applied just before the third node detectable stage under non water stressed and water stressed conditions gave slight increases in yield of up to 14% except for line Rht10 which increased significantly in non-stressed conditions. In the second glasshouse experiment, a rate of 2.5 1 ha" applied at the start of stem elongation under 30% FC and 100% FC gave reductions in yield up to 16% for the growth regulator and 55% under water stress. In the field experiment, rates of 2.5 and 3.0 1 ha-1 applied at the start of stem elongation gave reductions in yield up to 20% mainly through individual seed weight. In the final glasshouse experiment, rates of 2.5 and 3.0 1 ha-l applied at 6 leaves unfolded and 1st node detectable both reduced grain yield.
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Snelson, Jonathan Bundy. "Plant Growth and Root Zone Management of Greenhouse Grown Succulents." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32398.
Full textAbstract:
Effects of media, soil moisture, fertility rate, and plant growth regulators on plant growth were investigated for 13 taxa of succulents.
Media: Liners were grown in five common greenhouse substrates: 80% peat, 60% bark + 30% peat moss, 80% pine bark/20% Permatil (v/v), 100% composted pine bark, or whole tree substrate until market ready. Overall, higher percentage bark mixes yielded smaller plants, with lower shoot dry weights, shoot heights and widths.
Soil Moisture: Liners were potted into a 60% bark/30% peat soilless potting mix. In group 1 , irrigation to container capacity occurred when volumetric soil moisture content fell below 30%, 20%, or 10%,. Group two (seven species) irrigation thresholds were shifted to 35%, 25%, and 15%. Effects of irrigation rate were significant in three of the 13 species studied, and those effects were species-specific.
Fertility Rate: Liners were potted into60% bark/30% peat substrate. Fertility reatments in group were 0, 50, 100, or 200 mg.L-1 nitrogen. Group 2 plants received treatments of 50, 150, 250, or 350 mg.L-1 nitrogen. Four of the 11 species studied were affected by nitrogen rate, with rates up to 200 mg.L-1 generally producing the largest plants.
PGRs: Seven species were potted into a 60% bark/30% peat substrate. Group one plants were treated with a foliar application of benzyladenine (Configure) at rates of 0, 400, 800, or 1600 mg.L-1. Group 2 plants were treated either BA at 0, 250, 500, or 1000 mg.L-1, dikegulac sodium (Augeo) at 400, 800, or 1600 mg.L-1, or a tank mix of 500 mg.L-1 Configure and 800 mg.L-1 Augeo. BA caused an increase in branches leaders or offsets in two species.Master of Science
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Deveson, M. R. "Effects of plant growth regulators on root growth and root/shoot integration in wheat (Triticum aestivum L.)." Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376235.
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Lombard, Petrus Johannes. "A biochemical study of budbreak and plant growth regulators in table grapes." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52617.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2002.ENGLISH ABSTRACT: The cultivation of table grapes in the warmer areas of South Africa, indeed worldwide, is complicated by rest breaking problems in spring due to delayed budbreak. In order to overcome these problems rest breaking agents, mainly hydrogen cyanamide, are applied. However, instead of alleviating the problem, additional problems such as uneven budbreak and reduced production are often induced. This study was initiated to further understand the physiological processes occurring during budbreak and how the application of hydrogen cyanamide influences these processes. The following aspects were investigated in this study: a. The effect of hydrogen cyanamide on tissue cytokinin (specifically zeatin riboside) levels of Sultanina table grape vines after application at different times before natural budbreak was studied over two seasons. In 1997, hydrogen cyanamide was applied at three weeks before induced budbreak and in 1998 at six weeks before induced budbreak. One year-old canes were sampled weekly after hydrogen cyanamide application, divided into distal and proximal sections, then further divided into buds, bark and wood tissues and the zeatin riboside (ZR) levels determined. A relatively high amount of chilling coupled to late hydrogen cyanamide application in 1997 led to a large effect on ZR release, but did not lead to significant shifting of the budbreak pattern. Zeatin riboside peaks were observed in buds, internode wood and bark of treated vines compared to control vines. The peaks were higher in distal portions compared to proximal portions in all tissues. The relatively lower chilling and earlier application of hydrogen cyanamide in 1998 had a larger effect on the budbreak pattern while the bud ZR peak was shifted earlier. The distal portion bud ZR . peak was again higher than the proximal portion bud ZR peak. In 1997, as sampling was not initiated early enough, bud ZR peaks were only observed after budbreak, while in 1998 bud ZR peaks were observed before and after budbreak. The effect of these ZR increases on the development of inflorescence primordia, subsequent bunch development and ultimately production, are discussed. b. Free xylem sap was sampled at cane and spur pruned lengths from unpruned canes of Sultanina from budswell until after budbreak in 1999 and from three table grape cultivars, i.e Sultanina, Alphonse Lavalleé and Sunred Seedless, in 2001 and ZR levels determined. The ZR levels in the buds of these three table grape cultivars, pruned to different cane lengths were also determined. One year old canes of these cultivars, were each pruned to long canes (14 buds) and short spurs (2 buds). The ZR content in buds of these canes at distal and proximal positions were determined weekly from budswell until after budbreak in 1999. Xylary ZR peaks occurred before 50% budbreak. Spur xylary ZR levels of all three cultivars followed a similar pattern, although at lower ZR levels than that of the canes. This is similar to previous studies on xylary ZR levels of apple shoots. The high levels of free ZR found in xylem sap at the distal portions of canes support the hypothesis of a cumulative ZR build-up effect as cane length increases. Spur pruning resulted in earlier budbreak and a higher final budbreak than cane pruning. The proximal portions of shoots, whether spur pruned or the proximal portions of canes, showed elevated ZR levels in all cultivars. This difference in ZR levels in bud tissue of different portions of the cane would suggest a difference in ZR consumption or turnover. The results of this study have important management implications for the cultivation of vines in warmer areas in which hydrogen cyanamide is used to alleviate budbreak problems.
AFRIKAANSE OPSOMMING: Die verbouing van tafeldruiwe in die warmer gebiede van Suid-Afrika, soos straks wêreldwyd, word bemoeilik deur rusbreekprobleme in die lente weens vertraagde bot. Rusbreekmiddels, meestal waterstofsiaanamied, word gevolglik toegedien om hierdie probleme te probeer oorkom. In plaas van opheffing van die probleem, veroorsaak hierdie toedienings somtyds addisionele probleme soos ongelyke bot en verlaagde produksie. Hierdie studie is aangepak om die fisiologiese prosesse wat tydens bot plaasvind, beter te verstaan, asook hoe die toediening van waterstofsiaanamied hierdie prosesse beïnvloed. Die volgende is in hierdie studie ondersoek: a. Die invloed van waterstofsiaanamied op lootweefsel sitokinien (naamlik zeatin ribosied, ZR) vlakke van 'n Sultanina tafeldruif wingerd is oor twee seisoene ondersoek na toediening op verskillende tye voor bot. Waterstofsiaanamied is in 1997 drie weke en in 1998 ses weke voor geïnduseerde bot toegedien. Een jaar oue lote is weekliks gemonster na waterstofsiaanamied toediening, verdeel in apikale en basale gedeeltes en verder verdeel in ogies, bas en houtweefsel en die ZR vlakke bepaal. Relatief hoër vlakke koue, gekoppel met later watersiaanamied toediening het in 1997 tot 'n groot effek op ZR vlakke gelei, maar het nie die botpatroon wesentlik verskuif nie. Zeatin ribosied pieke is waargeneem in ogies, internode hout en bas van behandelde wingerd in vergelyking met kontrole wingerd. Die pieke was hoër in apikale gedeeltes in vergelyking met basale gedeeltes in alle weefsels. Die relatief laer koue en vroeër toediening van waterstofsiaanamied in 1998 het 'n groter effek op die botpatroon gehad, terwyl die ogie ZR piek vroeër geskuif is. Die apikale gedeelte se ogie ZR piek was weereens hoër as die basale gedeelte se ogie ZR piek. Monstering was nie vroeg genoeg begin in 1997 nie, aangesien ogie ZR pieke slegs na bot waargeneem is, terwylogie ZR pieke in 1998 voor en na bot waargeneem is. Die effek van hierdie verhoging in ZR vlakke op die ontwikkeling van blom primordia, daaropvolgende tros ontwikkeling en uiteindelik produksie, is bespreek. b. Vry xileemsap is gemonster van langdraer en kortdraer gedeeltes van ongesnoeide lote van Sultanina vanaf ogieswel tot na bot in 1999 en vanaf drie tafeldruif kultivars, naamlik Sultanina, Alphonse lavalleé en Sunred Seedless, in 2001 en die ZR vlakke bepaal. Die ZR vlakke van ogies van hierdie drie kultivars, gesnoei tot verskillende lootlengtes is ook bepaal. Eenjarige lote van hierdie kultivars is gesnoei tot langdraers (14 ogies) en kortdraers (2 ogies). Die ZR vlakke in ogies geleë op apikale en basale gedeeltes van hierdie lote is weekliks in 1999 bepaal vanaf ogieswel tot na bot Xileemsap ZR pieke is waargeneem voor 50% bot. Kortdraer xileemsap ZR vlakke het 'n soortgelyke patroon as die langdraers gevolg vir al drie kultivars, alhoewel teen laer ZR vlakke as die langdraers. Hierdie waarneming is soortgelyk aan vorige studies op xileemsap ZR vlakke van appel lote. Die hoë ZR vlakke gevind in die xileemsap van die apikale gedeeltes van lote ondersteun die hipotese van 'n kumulatiewe opbou van ZR soos die lengte van die loot toeneem. Die snoei van lote as kortdraers het gelei tot vroeër bot en 'n hoër finale bot persentasie as die snoei van langdraers. Die basale gedeeltes van lote het verhoogde ZR vlakke in al drie kultivars getoon, onafhanklik van die feit dat dit vanaf die kortdraer of die basale gedeelte van 'n langdraer was. Hierdie verskil in ZR vlakke in ogie weefsel van verskillende gedeeltes van die loot impliseer 'n verskil in ZR verbruik of omset. The resultate van hierdie studie het belangrike bestuursimplikasies vir die verbouing van wingerd in warmer gebiede, waar waterstofsiaanamied gebruik word om botprobleme te oorkom.
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Abdul-Razak, Mubarak Ali. "INFLUENCE OF GROWTH REGULATORS AND FERTILIZERS ON COTTON YIELD AND PLANT BEHAVIOR." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/184196.
Full textAbstract:
The effect of the plant regulator Mepiquat chloride (PIXᵀᴹ) (1,1-dimethyl-piperidinium chloride), in the early flowering stage, and combinations with soil and foliar application of fertilizers was investigated through seven field experiments conducted in 1982 and 1983 at three University of Arizona experimental locations. Three upland cotton cultivars (Gossypium hirsutum L.), 'Deltapine 55', '61' and '62' were used. Cotton yield, boll properties, fiber properties, leaf chlorophyll content, plant height, plant partitioning and maturity were investigated. Petiole nitrate, leaf area index (LAI) and LAI interrelationship with yield were also included in this study. The use of PIX resulted in an increase in seed cotton yield and boll weight in one of the experiments, while fiber properties did not show any significant response to either PIX or fertilizers. PIX, however, had the tendency to enhance maturity by about 1 week. Use of PIX reduced plant height in all tested cultivars at all locations. The reduction in plant height ranged from 7 to 28% depending on the cultivar, location and the amount of PIX applied. The chlorophyll a and b content of leaves increased significantly as a result of PIX application in two of four tests, while their ratio decreased. Leaf area index between treatments were not significantly different except at one sampling date. In a regression study, however, yield was found to be related positively to LAI when soil and foliar application of fertilizer were added, while it was negative when PIX was applied. Neither PIX nor BALANCEᵀᴹ (1:18:18:1) application affected plant partitioning nor petiole nitrate concentration at most of the sampling dates.
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Rethwisch, Michael D., Michael D. Kruse, and Justin Parker. "Effects of Aerially Applied Plant Growth Regulators on Alfalfa Quality and Yields." College of Agriculture, University of Arizona (Tucson, AZ), 1996. http://hdl.handle.net/10150/202434.
Full textAbstract:
Plant growth regulators were aerially applied on April 26, 1996, to two alfalfa fields, one (Cibola) in its first year of production and the other field (CUF 101) in its third year. The first year field was approximately 50% through the cutting cycle and the third year field was approximately 30% through the cutting cycle when applications were made. No statistical differences were noted in hay tonnage the first cutting after application. Yield increases due to treatments were noted in the second cutting and maximum increases ranged from 277 -461 lbs of hay per acre. No yield or quality differences were noted the third cutting after application. The two fields differed in their response. The lowest rates of plant growth regulators produced higher yields in the first year field, but these treatment rates had greatly lowered hay quality the previous cutting. These effects were not noticed in the third year stand field. Increased hay tonnage was noted in the third year field from the 16 oz/acre rates, but was not evident in the first year field. Hay quality was usually highest in the check the first two cuttings after treatment. It is unknown if the differences noted between the two fields are due to different age of plants, variety and/or stage of growth when treatments were applied.
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Rethwisch, Michael D., Greg Hurtado, and Rosario Hurtado. "Comparison of Various Plant Growth Regulators on Pima S-7 Cotton Yields." College of Agriculture, University of Arizona (Tucson, AZ), 1996. http://hdl.handle.net/10150/210772.
Full textAbstract:
All plant growth regulators and nutritional products applied to Pima S-7 cotton during bloom economically increased lint yields, with increases ranging from 80 - 261 lbs. /acre. Greatest increase was noted with Boll-Set Plus, a product that contains raised levels of calcium and zinc. Cytokin and Boll -Set Plus significantly increased yields at one location. A lint yield increase of approximately 40 lbs/acre was noted when Tech-Flo Alpha was added to Cytokin. A single application of Foliar Triggrr resulted in equal yields as two applications of the Cytokin plus Tech-Flo Alpha.
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McCarthy, Timothy James. "Studies towards the total synthesis of (+)-ovalifoliene and other plant growth regulators." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314551.
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Grossman, Mara Celeste. "Use of Plant Growth Regulators to Improve Branching of Herbaceous Perennial Liners." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32830.
Full textAbstract:
The objective of this study is to evaluate the efficacy of PGRs to improve branching during
production of herbaceous perennial liners and finished plants. The effects of benzyladenine (BA)
on the branching and root and shoot growth of Agastache Clayt. Ex Gronov. 'Purple Hazeâ ,
Gaura lindheimeri Engelm. & A. Gray 'Siskiyou Pink', Lavandula à intermedia Emeric ex
Loisel. 'Provence', Leucanthemum à superbum (Bergmans ex J.W. Ingram) Bergmans ex Kent.
'Snowcap', and Salvia à sylvestris L. (pro sp.) 'May Night' was tested. Root dry weight was found
to be highly correlated to root volume and root surface area. In liners, all taxa except Salvia had
increased branching while all except Gaura had reduced rooting. Increased branching was not
evident in most taxa as finished plants. The effects of BA on Aster 'Professor Anton Kippenbergâ
(Symphyotrichum novi-belgii L.'Professor Anton Kippenburg'), Campanula punctata Lam.
'Cherry Bells,' Cosmos atrosanguineus (Hook) Voss., Verbena bonariensis L. 'Lollipop,'
Rosmarinus officinalis L.'Hill Hardy' and Veronica spicata L. â Goodness Grows.â was tested. BA
increased branching of three taxa as liners while roots were not affected. The addition of IBA did
not improve root growth in BA-treated plants. Dikegulac sodium and ethephon were evaluated as
branching enhancers in the same six perennials. Dikegulac increased branching of all except
Campanula while ethephon increased branching in Veronica and Verbena. The effects of
application time of BA on the branching of Agastache Clayton ex Gronov. â Tutti Fruttiâ and
Verbena bonariensis 'Lollipop' was evaluated with application of BA at 0, 7, 14, 17, 20 and 21
days after sticking (DAS); however growth was reduced in plants treated before rooting had
occurred. Agastache finished plants treated at 14 DAS had increased branching whereas
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branching was not affected in Verbena liners or finished plants. The effects of single or multiple
applications of BA and dikegulac sodium on Sedum spectabile Boreau â Autumn Joy,' Gaillardia
aristata Pursh â Gallo Red,â Phlox paniculata L. â Bright Eyes,â Nepeta racemosa Lam. â Walkerâ s
Low,â Delosperma NE Br. â Table Mountain,â and Achillea L. â Moonshineâ were evaluated. Two
applications of PGR was most effective at increasing branching in finished plants. High rates of
dikegulac sodium reduced growth in most plants studied while BA increased branches without
negatively affecting plant growth.Master of Science
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Zhou, Dongfang. "Using Plant Growth Regulators to Improve the Quality of Containerized Herbaceous Peony." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/98808.
Full textAbstract:
Herbaceous peonies (Paeonia lactiflora Pall.) are common perennials used both in gardens and the landscape as well as for cut flowers. Peonies require a chilling period to break dormancy but not for flower bud differentiation. For all studies discussed in this dissertation, two peony cultivars, Sarah Bernhardt and Inspecteur Lavergne, small (3–5 eye) crowns from Holland were potted in 3.8-L pots in mid-November of 2017 and 2018. Our overall objective was to determine if we could manipulate chilling time, along with application of gibberellic acid (GA3) and growth retardants, to produce marketable containerized peonies from a small crown in a single season (November to May).
We evaluated chilling, GA3 and a growth retardant (uniconazole; UNZ) under controlled chilling and greenhouse forcing conditions. All potted plants were held outdoors at Battlefield Farms (Rapidan, VA, 38˚ N) for 4 weeks [in 2017, 400 chilling units (CU) according to Fulton Chilling Model] or in a 10°C cooler for 5.5 weeks (in 2018, 400 CU) to root, then placed in a 5°C cooler for 3, 4 or 5 weeks (total 752, 869 or 986 CU). GA3 was applied as a 0 or 100 mg·L-1 drench at 250 ml/pot after the plants were moved into the Virginia Tech greenhouse (Blacksburg, VA, 37˚ N) for forcing. Uniconazole drenches were applied to each cultivar under each chilling treatment at 355 ml/pot at 0, 15, or 20 mg·L-1 at 7 days after the GA3 drench applications. Three weeks chilling at 5°C (752 CU total) provided sufficient chilling for 'Sarah Bernhardt' and 'Inspecteur Lavergne'. Application of GA3 reduced production time and resulted in a greater number of shoots, and, in three of the four studies, increased the number of flowering shoots in three of the four studies. Substrate drench application of 15 mg·L-1 UNZ prior to spring emergence reduced plant width moderately resulting in improved compactness of both cultivars.
We evaluated the effects of plant growth retardants applied with different methods at different stages of production on the growth and development of containerized peony under nursery conditions. All potted plants were placed in an unheated coldframe at the Virginia Tech Urban Horticulture Center (Blacksburg, VA, 37˚ N) for one month after potting to promote rooting and then were moved outdoors to a gravel pad to receive natural chilling from November to February. In 2017–18, substrate drenches of UNZ at 0, 15, 30 or 45 mg·L-1 or paclobutrazol (PBZ) at 0, 30, 60 or 90 mg·L-1 at 237 mL/pot were applied about 4 weeks after potting for both cultivars in mid-December 2017. In 2018–19, fall drenches of uniconazole at 0, 15, 30 or 45 mg·L-1 at 237 mL/pot were applied about 4 weeks after potting in mid-December 2018, or spring sprenches of uniconazole were applied at 0, 15, 30 or 45 mg·L-1 at 840 mL·m-2 in March 2019 after 50% shoot emergence for each cultivar. Plant growth retardant applications had little effect on plant growth of either cultivar, but treated plants were of a darker green color compared to the control plants. In addition, higher rates of uniconazole applied as a fall drench increased the number of flowering shoots of both cultivars and the percentage of plants flowering for 'Sarah Bernhardt' in the second season of the study where plants were more protected from spring freezes. Fall paclobutrazol drenches or spring uniconazole sprenches had little effect on flowering.
To determine the best timing for spring GA3 applications under nursery conditions, we applied three models based on natural chilling accumulation. The models were a modified Fulton Chilling Model (FCM) for herbaceous peonies, Blackberry Chilling Model 5 (BCM5) for blackberry, or a visual development model (VDM) which was 10% of plants showing shoot emergence in the spring. We choose 1,000 CU for the first two chilling models as the chilling required to break dormancy and promote normal plant growth and flowering. All plants were held in an unheated coldframe at the Virginia Tech Urban Horticulture Center for one month after potting to promote rooting, then were moved outdoors to a gravel pad to receive natural chilling over the winter months. Drenches of 0 or 100 mg·L-1 GA3 were applied at 250 mL/pot to each cultivar under each chilling model when the specific conditions were met. Due to greater winter injury in the 2017–18 season, results varied by year. In the 2017–18 season, GA3 applied according to BCM5 reduce days to emergence for both cultivars and reduce the plant width of 'Inspecteur Lavergne', and later application according to BCM5 and VDM reduced plant length and diameter of 'Sarah Bernhardt'. Reductions in plant size may have been due to greater winter injury due to the earlier emergence of GA3 treated plants. In the 2018–19 season, earlier GA3 drench applications tended to reduce days to emergence for both cultivars and the FCM application reduced days to bud for 'Inspecteur Lavergne', but GA3 drench applications had no effect on plant size. GA3 can be applied after chilling (1,000 CU) using a suitable chilling model such as FCM for peonies, or BCM5, or VDM, but GA3 had little effect on plant development under nursery conditions.
We also evaluated GA3 effects on peony bud differentiation and development during controlled chilling and early forcing, as well as effects on growth and flowering. All potted plants were held in a 10°C cooler for 5.5 weeks (400 CU) to root, then placed in a 5°C cooler for 4 weeks (total 869 CU). GA3 was applied at 0 or 100 mg·L-1 pre-chilling or post-chilling as a 250 ml/pot drench. Bud differentiation and development of excised buds were evaluated using a stereomicroscope at potting, after rooting (before chilling), after 1, 2, 3 or 4 weeks of chilling, and at 5, 10 or 15 days after the beginning of forcing. All buds were removed from the sample plants, measured for bud length and diameter, and dissected under a stereomicroscope to assess differentiation stages. Root dry weights and crown dry weights were also determined after rooting, after chilling, and at 15 days of forcing. Ten plants of each treatment were grown in the Virginia Tech greenhouse after chilling until flowering. GA3 applications did not advance the bud development stage because most of buds were already in the reproductive stages before dormancy, but GA3 enhanced bud elongation during chilling and the early forcing period. Our findings suggest that GA3 applications can reduce the time to emergence and flowering, as well as increase the numbers of shoots and flowering shoots. GA3 applied right after rooting in, prior to the chilling period, or before greenhouse forcing, resulted in earlier emergence and flowering with higher quality plants. However, earlier applications, pre-chilling, tended to produce plants with more shoots.
Overall, our experiments indicate that three weeks of chilling at 5°C (752 CU total) is a sufficient chilling regime for forcing 'Sarah Bernhardt' and 'Inspecteur Lavergne' peonies, and 1,000 CU of naturally accumulated chilling is sufficient for nursery production. GA3 applications can reduce the time to emergence and flowering, as well as increase the numbers of total shoots and flowering shoots. Timing of GA3 application is flexible; it can be applied right after rooting, before the chilling period, just before greenhouse forcing, or after shoots have begun to emerge. Plant growth retardant applications had a little effect on the growth of tested cultivars, but all plants treated with growth retardants are generally darker green in color. Additionally, growth retardant applications have some positive effects on flowering.Doctor of Philosophy
Herbaceous peonies (Paeonia lactiflora Pall.) are common perennials used both in gardens and the landscape as well as for cut flowers. Peonies require a chilling period to break dormancy but not for flower bud differentiation. For all studies, two peony cultivars, Sarah Bernhardt and Inspecteur Lavergne, 3 to 5 eye small crowns from Holland were potted in 3.8-L pots in mid November of 2017 and 2018. Our overall objective was to determine if we could manipulate chilling time, along with application of gibberellic acid (GA3) and growth retardants, to produce marketable containerized peonies from a small crown in a single season (November to May). We evaluated chilling, GA3 and a growth retardant (uniconazole) under controlled chilling and greenhouse forcing conditions. We evaluated the effects of plant growth retardants (uniconazole or paclobutrazol) applied with different methods (fall drenches or spring sprenches) at different stages of production on the growth and development of containerized peony under nursery conditions. To determine the best timing for spring GA3 applications under nursery conditions, we applied three models based on natural chilling accumulation. We also evaluated GA3 effects on peony bud differentiation and development during controlled chilling and early forcing, as well as growth and flowering. Overall, 3 weeks chilling at 5°C [752 chilling units (CU) total] is a sufficient chilling regime for forcing 'Sarah Bernhardt' and 'Inspecteur Lavergne' peonies, and 1000 CU naturally accumulated chilling is sufficient for nursery production. GA3 applications can reduce the time to emergence and flowering, as well as increase the numbers of shoots and flowering shoots. Timing of GA3 application is flexible, it can be applied right after rooting, after the chilling period, or after shoots have begun to emerge. Plant growth retardant applications had little effect on plant growth of either cultivar, but all plants treated with growth retardants were darker green in color. Additionally, growth retardant applications had some positive effects on flowering.
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Guan, Ming. "Steroids in plant development : effects and possible role of brassinosteroids and estrogens." Thesis, University of Exeter, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328469.
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Norton, E. R. "Scheduling Techniques for the Use of Pentia Plant Growth Regulator." College of Agriculture, University of Arizona (Tucson, AZ), 2005. http://hdl.handle.net/10150/198162.
Full textAbstract:
A single field study was conducted at the University of Arizona Safford Agricultural Center during the 2004 season to evaluate the utilization of a feedback technique that is based upon plant growth and development to schedule applications of the new plant growth regulator (PGR) from BASF, Pentia. A simple three treatment study was constructed consisting of a control treatment (no Pentia application), a scheduled treatment (application of 16 oz/acre at first bloom regardless of plant growth), and a feedback treatment (applications based upon plant growth and development). Application decisions on the feedback treatment were made using height to node ratios (HNR) as a measure of plant vigor. Treatment applications were made on the scheduled regime on 14 July with a one time 16 oz/acre application. The feedback regime received an application (16 oz/acre) of Pentia five days later on 19 July. An additional application (16 oz/acre) was made on the feedback treatment on 3 August due to continued high HNR levels. Significant differences in plant vigor were observed post application among the three treatments as measured by end of season HNR ratios. Yield results indicated positive lint yield response to Pentia application with both the scheduled and feedback treatment producing statistically higher yields than the control. Differences between the feedback and scheduled treatments were not statistically different however a slight yield increase was observed in the scheduled treatment. The second Pentia application made to the feedback treatment was not necessary. End of season HNR measurements indicate that the additional 16 oz/acre application suppressed growth to below the average baseline for HNR. These results indicate that potential positive response to PGR applications, specifically Pentia, under conditions of high vigor.