Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-05-12T16:53:39Z No. of bitstreams: 1 texto completo.pdf: 788309 bytes, checksum: 525e980e1f7503355a2db04d96f1d5f0 (MD5) / Made available in DSpace on 2017-05-12T16:53:39Z (GMT). No. of bitstreams: 1 texto completo.pdf: 788309 bytes, checksum: 525e980e1f7503355a2db04d96f1d5f0 (MD5) Previous issue date: 2004-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos de concentrações de paclobutrazol (PBZ) e ácido giberélico (AG3) sobre o desenvolvimento de plantas de limoeiro ‘Volkameriano’. O trabalho foi desenvolvido em casa de vegetação no Departamento de Fitotecnia da Universidade Federal de Viçosa, Minas Gerais, Brasil, de julho de 2002 a março de 2003. O experimento foi montado em esquema fatorial 4 X 2, sendo quatro concentrações de PBZ (0, 75, 150 e 225 mg do i.a. planta-1) e duas de AG3 (0 e 20 mg do i.a. L-1), no delineamento em blocos casualizados, com quatro repetições, tendo cinco plantas por unidade experimental. Para execução do experimento foram usadas plantas de limoeiro ‘Volkameriano’ com seis meses de idade e, aproximadamente, 32 cm de altura, em recipientes de 2,5 dm2. O PBZ foi aplicado na forma de solução, sobre o substrato, em dose única, com volume de 50 mL por recipiente. O ácido giberélico foi aplicado em quatro pulverizações com intervalos de dez dias, direcionado às folhas das plantas. Aos 50 dias após o início da aplicação dos tratamentos foram avaliadas a massa da matéria fresca, massa da matéria seca, comprimento de caule e de entrenós, diâmetro de caule, número de folhas, área foliar e unidades SPAD. Concentrações crescentes de PBZ reduziram o comprimento de caule, o comprimento médio dos entrenós, e a massa da matéria seca do total de raízes. O AG3 reverteu parcialmente os efeitos do PBZ para comprimento do caule e de entrenós. Para a massa da matéria seca do total de raízes a maior redução foi na presença de AG3, que agiu como inibidor do crescimento das raízes. As concentrações crescentes de PBZ aumentaram a massa foliar relativa, tanto na presença como na ausência de AG3. Na ausência de AG3, o aumento das concentrações de PBZ, aumentou a massa foliar específica, as unidades SPAD e a relação raiz/parte aérea, enquanto na presença de AG3 não houve efeito das concentrações de PBZ. Na ausência de AG3 concentrações crescentes de PBZ reduziram a área foliar e a massa da matéria seca do total da planta. A presença do AG3 reverteu esse efeito. O número de folhas não foi influenciado pelas concentrações crescentes de PBZ, mas a presença de AG3 aumentou o número de folhas. Para a variável diâmetro de caule verificou-se comportamento quadrático em função das concentrações de PBZ na presença de AG3, com máximo de 0,973 cm na concentração de 90,0 mg planta-1. O aumento das concentrações de PBZ, na ausência de AG3, apresentou comportamento de forma quadrática para os valores de massa da matéria seca de folhas, caule; portanto, da parte aérea, como também para a massa caulinar específica. A concentração estimada de PBZ que mais reduziu a massa da -1 matéria seca para folha foi -1 175,28 mg planta ; para caule, foi 181,39 mg planta ; para a parte aérea, foi 193,08 mg planta-1; e a maior redução de massa caulinar específica, foi para a concentração de 160,0 mg planta-1; na presença de AG3 não houve efeito de PBZ em nenhuma das características citadas. / This work was carried out to evaluate the effects of concentrations of paclobutrazol (PBZ) and giberellic acid (AG3) on the development of ‘Volkameriano’ lemon plants under greenhouse conditions at the Department of Plant Sciences of the Universidade Federal de Viçosa, Minas Gerais, Brazil, from July 2002 to March 2003. The experiment was arranged in a 4 X 2 factorial scheme, with four concentrations of PBZ (0, 75, 150 and 225 mg of i.a. plant-1) and two concentrations of AG3 (0 and 20 mg of i.a. L-1), in a randomized block design with four repetitions and 5 plants per experimental unit. Six-month-old ‘Volkameriano’ lemon plants, approximately 32 cm high, sown in 2.5 dm recipients were used. A single dose of PBZ solution was applied on the substrate, 50 mL volume per container. Giberellic acid was applied on the plant leaves four times at ten day-intervals. Fresh matter mass, dry matter mass, stem and internode length, stem diameter, number of leaves, leaf area and SPAD units were evaluated fifty days after the start of the treatment application. Increasing PBZ concentrations reduced stem length, average inter node length, and dry matter mass of the root total. AG3 partially reversed the PBZ effects for stem and internode length. For dry matter mass of the root total, the greatest reduction occurred in the presence of AG3, which acted as inhibitor of root growth. Increasing concentrations of PBZ increased the relative leaf mass, both in the presence and absence of AG3. In the absence of AG3, increased PBZ concentrations increased specific leaf mass, SPAD units, and the root/aerial part ratio, while in the presence of AG3 there was no effect of PBZ concentrations. In the absence of AG3, the increasing concentrations of PBZ reduced the leaf area and dry matter mass of the plant total. AG3 presence reversed this effect. The number of leaves was not influenced by increasing PBZ concentrations but the presence of AG3 increased the number of leaves. For the variable stem diameter, a quadratic behavior was verified as a result of PBZ concentrations in the presence of AG3, with a maximum of 0.973 cm at a concentration of 90.0 mg plant-1.Increased PBZ concentration in the absence of AG3 presented a quadratic behavior for the values of leaf and stem dry matter mass, i.e., the aerial part, as well as for the specific stem mass. The estimated PBZ concentration that reduced leaf dry matter mass the most was 175.28 mg plant-1; for the stem, 181.39 mg plant-1; for the aerial part, 193.08 mg plant-1; and the greatest reduction of specific stem mass was for the concentration of 160.0 mg plant-1; no PBZ effect on any of the characteristics cited was found in the presence of AG3.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2015-12-04T16:39:26Z No. of bitstreams: 1 texto completo.pdf: 938207 bytes, checksum: edad6a0ebef524fe413d5c98f09c4bed (MD5) / Made available in DSpace on 2015-12-04T16:39:26Z (GMT). No. of bitstreams: 1 texto completo.pdf: 938207 bytes, checksum: edad6a0ebef524fe413d5c98f09c4bed (MD5) Previous issue date: 2015-07-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O cultivo de pimenteiras como planta ornamental de vaso e corte tem se expandido consideravelmente no Brasil e no mundo. Foi realizado um experimento durante a produção de pimentas ornamentais envasadas com o objetivo de avaliar o efeito do paclobutrazol no crescimento e qualidade ornamental de duas variedades comerciais de pimentas (Iracema Biquinho Vermelha e Bode Amarela), e em dois acessos do banco de germoplasma da Universidade Federal da Paraíba (2334PB e 2345PB). Outros cinco experimentos pós-colheita utilizando pimenteiras ornamentais de corte foram realizados. Quatro deles utilizando as cultivares ‘Rio Light Orange’ e ‘Cappa Rond Red’: 1- estágio de desenvolvimento e procedimentos na colheita, 2- duração e procedimentos do armazenamento a frio, 3-sensibilidade ao etileno e compostos anti- etileno, 4-tratamentos de desfolhação. O quinto experimento foi conduzido utilizando 10 cultivares de pimenteiras ornamentais, ‘Tall Round Yellow’, ‘Stromboli’, ‘Rooster’, ‘Rio Yellow’, ‘Rio Light Orange’, ‘On Top Round Orange’, ‘On Top Round Black’, ‘Cappa Round Red’, ‘Back Pearl’ e a cultivar 441525 da Universidade de Cornell, visando obter respostas pós-colheita a preservativos florais de hidratação e manutenção. No experimento de produção das pimenteiras envasadas, a utilização da concentração de 20 mg L-1 de paclobutrazol na variedade comercial Bode Amarela, e nas plantas do acesso 2345PB resultaram em plantas com altura adequada a finalidade de ornamentação, sem alterar as características dos frutos e sem apresentar sintomas de fitotoxidade. Nos experimentos pós-colheita, a vida de vaso de hastes da cultivar ‘Rio Light Orange’ foi prolongada quando colhidas com frutos parcialmente maduros. O estágio de desenvolvimento do fruto na colheita não afetou a vida de vaso da cultivar ‘Cappa Round Red’. Nas duas cultivares, quando colhidas e mantidas em água, as hastes mostraram menor incidência de murcha da folhagem. O armazenamento a frio, em água, foi tolerado por até uma semana pela cultivar ‘Rio Light Orange’ e por até duas semanas pela cultivar ‘Cappa Round Red’. Essas cultivares não responderam ao etileno exógeno na concentração de 1.0 μL L-1 for 16h, e agentes anti-etileno tiveram mínimo efeito nas características pós-colheita. Os tratamentos de desfolhação aplicados nesse estudo não mostraram clara resposta, portanto, não é possível fazer nenhuma recomendação quanto a remover com sucesso a folhagem de pimentas ornamentais sem reduzir a vida de vaso. Uso de solução de manutenção, independentemente do uso prévio de solução de hidratação, prolongou a vida de vaso das pimentas ornamentais ‘Black Pearl’, ‘Rooster’ e ‘Stromboli’. Em geral, o uso de solução de hidratação ou reduziu ou não teve efeito na vida de vaso e portanto, não deve ser usado. Além disso, uso de solução de manutenção manteve a folhagem túrgida por mais tempo. A vida de vaso das pimentas ornamentais ‘Rio Light Orange’ e ‘Cappa Round Red’ pode ser prolongada seguindo apropriados procedimentos de manuseio pós-colheita. O uso de solução de manutenção pode ser benéfico para à vida de vaso e a qualidade da folhagem de várias cultivares de pimentas testadas nesse estudo. / The peppers growth as a pot ornamental plant has been expanded considerably in Brazil and in the world. An experiment was conducted during the production of potted ornamental peppers in order to evaluate the effect of paclobutrazol in the growth and ornamental quality of two commercial varieties of peppers (Iracema Biquinho Vermelha and Bode Amarela), and in two accesses of the germoplasm bank of Federal University of Paraíba (2334PB and 2345PB). Other five postharvest experiments using cut ornamental peppers were conducted. Four of them using the cultivars ‘Rio Light Orange’ and ‘Cappa Round Red’: 1-harvest stage and procedures, 2-cold storage and duration, ethylene sensitivity and anti-ethylene compounds, 4-defoliation treatments. The fifth experiment was conducted using 10 varieties of ornamental pepper, ‘Tall Round Yellow’, ‘Stromboli’, ‘Rooster’, ‘Rio Yellow’, ‘Rio Light Orange’, ‘On Top Round Orange’, ‘On Top Round Black’, ‘Cappa Round Red’, ‘Back Pearl’ and the cultivar 441525 from Cornell University to identify postharvest responses to commercial hydrator and holding floral preservatives. In the ornamental pepper production, the use of paclobutrazol 20 ppm concentration in the commercial variety Bode Amarela and in the access 2345PB resulted in plants with suitable height for the purpose of ornamentation without changing the characteristics of fruits and without phytotoxicity symptoms. In the postharvest experiments, vase life of ‘Rio Light Orange’ stems was extended when harvested with fruits partially mature. The stage of development of the fruits at harvest did not affect the vase life of the cultivar 'Cappa Round Red'. In both cultivars, when harvested and kept in water, stems showed less incidence of wilted foliage. Cold storage, in water, was tolerated for up to one week for the cultivar ‘Rio Light Orange’ and for up to two weeks for the cultivar ‘Cappa Round Red’. These cultivars did not respond to exogenous ethylene at a concentration of 1.0 uL L-1 for 16h and anti-ethylene agents had minimal effect on postharvest characteristics. Defoliation treatments applied in this study did not show a clear response and therefore it is not possible make any recommendations on how to successfully remove the foliage of ornamental peppers without reducing vase life. The use of a holding solution, regardless of prior use of a hydrator solution increased vase life of ‘Black Pearl’, ‘Rooster’ and ‘Stromboli’ ornamental peppers. In general, use of a commercial hydrator either reduced or had no effect on vase life and thus, should not be used. Moreover, use of a holding solution kept the foliage turgid longer. Vase life of ‘Rio Light Orange’ and ‘Cappa Round Red’ ornamental peppers can be extended following proper postharvest handling procedures and the use of a holding solution can be beneficial on vase life and in the foliage quality of many cultivars of peppers tested in this study.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2015-12-14T14:36:12Z No. of bitstreams: 1 texto completo.pdf: 901400 bytes, checksum: 9f06efc542dae099167e6908ab50fbe2 (MD5) / Made available in DSpace on 2015-12-14T14:36:12Z (GMT). No. of bitstreams: 1 texto completo.pdf: 901400 bytes, checksum: 9f06efc542dae099167e6908ab50fbe2 (MD5) Previous issue date: 2010-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A aplicação da maioria dos retardantes de crescimento, como paclobutrazol e daminozide, em espécies ornamentais, bloqueia etapas da via de biossíntese das giberelinas. O uso desses retardantes tem se revelado uma metodologia adequada para a manipulação da arquitetura de plantas de maior porte cultivadas em vasos, sem diminuição da produtividade. Objetivou-se com este estudo avaliar a produção, qualidade floral e os efeitos fisiológicos de cultivares de roseira (Yellow Terrazza® e Shiny Terrazza®) cultivadas em vaso em função da aplicação no substrato de doses de paclobutrazol (0; 0,5; 1,0; 1,5 e 2,0 mg/vaso); e detectar as alterações anatômicas quantitativas e os teores de clorofila das folhas de cultivares de roseira (Yellow Terrazza® e Red White Terrazza®) cultivadas em vaso em função da pulverização de doses de paclobutrazol (0, 40, 60, 80 mg L-1) em um experimento, e de doses de daminozide (0, 2000, 4000, 6000, 8000 mg L-1) em outro. Os experimentos foram conduzidos em casa de vegetação e os tratamentos dispostos em esquema fatorial (cultivares x doses dos retardantes), em delineamento de blocos casualizados. Os dados foram submetidos à análise de variância e ajustadas equações de regressão para o efeito das doses dos retardantes com uso de variáveis indicadoras (Dummy). Nas cultivares Yellow Terrazza® e Shiny Terrazza®, com o aumento da dose de paclobutrazol aplicado no substrato, houve redução da produção de matéria seca da parte aérea e de folhas, área foliar, altura das plantas, altura do botão e diâmetro floral, e incremento da fotossíntese, transpiração, condutância estomática, teor de clorofila total e longevidade floral. Com aplicação foliar de paclobutrazol e daminozide, as cultivares Yellow Terrazza® e Red White Terrazza® apresentaram plasticidade anatômica da lâmina foliar. As maiores alterações foram observadas no tecido parenquimático. O aumento da dose pulverizada de paclobutrazol e daminozide para ambas cultivares promoveu mudanças na proporção dos tecidos, aumentando a espessura da lâmina foliar, mesofilo e dos parênquimas paliçádico e lacunoso, além dos teores de clorofila. A aplicação via substrato de paclobutrazol foi eficiente em reduzir a altura, conferindo relação harmoniosa entre a planta e o vaso, sem causar sintomas de toxidez. Sugere-se a aplicação no substrato de 2 mg/vaso de paclobutrazol para Yellow Terrazza® e Shiny Terrazza® cultivadas em vasos. / The application of most growth retardants such as paclobutrazol and daminozide in ornamental species, blocks steps in the gibberellins biosynthesis. The use of these growth retardants have been shown to be a suitable method for manipulating the architecture of large size plants grown in pots, without reducing productivity. The objective of this study was to evaluate the production, flower quality and physiological effects of rose cultivars (Yellow Terrazza® and Shiny Terrazza®) grown in pots in function of paclobutrazol doses (0, 0.5, 1.0, 1.5 and 2.0 mg/pot) applied in drench; and detect quantitative anatomical and the chlorophyll content of leaves of rose cultivars (Yellow Terrazza® and Red White Terrazza®) grown in pots in function of the spraying of paclobutrazol doses (0, 40, 60, 80 mg L-1) and daminozide doses (0, 2000, 4000, 6000, 8000 mg L-1). The experiments were conducted in a greenhouse and the treatments were arranged in a factorial scheme (genotype x retardant doses) in a randomized block design. Data were subjected to analysis of variance and regression equations were adjusted for the effect of retardant doses with the use of Dummy variables. In the cultivars Yellow Terrazza® and Shiny Terrazza®, the increasing of paclobutrazol doses applied in drench decreased the shoot and leaf dry matter production, leaf area, plant height, height and flower diameter also increased photosynthesis, transpiration, stomatal conductance, chlorophyll content and flower longevity. With foliar application of paclobutrazol and daminozide, cultivars Yellow Terrazza® and Red White Terrazza® showed leaf anatomical plasticity. The larger alterations were observed in the parenchyma tissue. Increasing the paclobutrazol and daminozide doses sprayed for both cultivars promoted changes in the proportion of tissues by increasing the leaf, mesophyll, palisade and spongy parenchyma thickness also chlorophyll content. The application of paclobutrazol in drench was effective in reducing the height, giving a harmonious relationship between plant and pot, without phytotoxicity. We suggest the application of 2 mg/pot of paclobutrazol in drench to potted Yellow Terrazza® and Shiny Terrazza® cultivars.

Made available in DSpace on 2014-06-11T19:32:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-11-07Bitstream added on 2014-06-13T20:04:01Z : No. of bitstreams: 1 mouco_mac_dr_botfca.pdf: 976151 bytes, checksum: 028a98e349191bffef5f2b0e8c7d42fa (MD5) / Outra / A mangicultura na região semi-árida destaca-se no cenário nacional não só pela expansão da área cultivada, volume de produção, altos rendimentos e qualidade do fruto produzido, mas também pela possibilidade de produção durante todo o ano devido às condições climáticas e às tecnologias para o manejo do crescimento vegetativo e da floração, com uso da irrigação, podas e utilização de reguladores vegetais. O paclobutrazol aplicado ao solo é utilizado no manejo da produção da mangueira na maioria dos pomares. Entretanto, há a necessidade de identificar outros reguladores vegetais que ofereçam a eficiência no manejo de produção das diferentes cultivares e que possam ser aplicados via foliar, de forma a minimizar os riscos de resíduo no solo e da aplicação de quantidades inadequadas ao longo dos anos. Assim, este trabalho teve como objetivo avaliar o efeito de reguladores vegetais aplicados via foliar quanto à eficiência no manejo da floração das cultivares Tommy Atkins e Kent, com maior precisão na recomendação da dose e menores riscos de contaminação da planta e do solo, permitindo o escalonamento da produção da mangueira. Os experimentos foram conduzidos na região do Vale do Rio São Francisco, em casa de vegetação, na Embrapa SemiÁrido e em condições de campo, nas Fazendas Frutavi e Andorinhas, localizadas no município de Petrolina, PE, entre outubro de 2005 e julho de 2008. Foram avaliados três reguladores vegetais aplicados via foliar: prohexadione-Ca, etil-trinexapac e cloreto de chlormequat, em duas doses, sendo estes comparados ao paclobutrazol aplicado ao solo, em delineamento de blocos ao acaso, com quatro repetições e duas plantas por parcela. Para a comparação do efeito dos tratamentos, registraram-se dados relativos à brotação vegetativa (percentagem e comprimento dos ramos), emissão de panículas (percentagem e comprimento),... / The mango crop within the semi-arid region stands out in the national scenario due to the expansion of the planted area, the production quantity, high yields and quality of the fruit produced, as well as to the possibility of all-year production due to climatic conditions and technologies that allow the management of plant growth and blossom, through irrigation, pruning and use of plant growth regulators. Paclobutrazol applied to the soil is used for the production management of mango in most of the orchards. However, it is necessary to identify other vegetal regulators that might be efficient for the production management of different cultivars and might be applied to the leaves, so as to minimize the risk of residues in the soil and inadequate application quantities over several years. Therefore, the present paper has the purpose to evaluate the effect of plant growth regulators that can be applied to the leaves, regarding their efficiency for the blossom management of the cultivars Tommy Atkins and Kent, allowing off season mango production with higher precision in dosage recommendation and lesser contamination risk for the plant and the soil. The experiments were carried out in the area of the São Francisco river valley, under green-house conditions at Embrapa Semi-Àrido, and under field conditions on the farms Frutavi and Andorinhas, both located in the municipality of Petrolina, Pernambuco state, from October 2005 to July 2008. Three plant growth regulators, sprayed to the leaves, were evaluated: prohexadione-Ca, trinexapac-ethyl and chlomequat cloride, applied in two dosages, and compared to paclobutrazol applied to the soil, using a randomized blocks design, with four replications and two plants per plot. In order to compare the effects of the treatment, data were recorded related to vegetative growth (percentage and length of the shoots), ...(Complete abstract, click electronic access below)

Moringa oleifera Lam. is a tree with great potential as it is fast growing and drought tolerant. Amongst the tree’s multitude of benefits, it can also be used to produce a biodiesel fuel. However, prior to the establishment of commercial plantations, all cultivation aspects of this promising tree have to be understood. Temperature is a significant climatic factor influencing both geographical plant distribution and growth, and since M. oleifera trees are naturally found in tropical climates around the world, the extent of their adaptability to cooler climates was the main objective of this study. Trees were cultivated from seed and germinated in a controlled greenhouse environment at the Experimental Farm of the University of Pretoria. After germination, 50% of the seedlings were hardened-off by placing them outside under ambient growing temperatures, while the rest remained inside the greenhouse. With trial commencement, 132 of both the hardened and non-hardened seedlings were planted into 10 ℓ plastic bags and randomly placed into three temperature-controlled greenhouses, each with a different fluctuating night/day temperature regime namely; 10/20°C ± 2°C, 15/25°C ± 2°C and 20/30°C ± 2°C. In addition, half the trees within each temperature regime were treated with the growth regulator paclobutrazol to determine its effect on growth/flowering at different temperatures. During the 224-day trial period, biweekly measurements of tree height, stem diameter and leaf area estimates of each individual tree within all three temperature regimes were taken. Despite germination percentages being slightly higher at the low 10/20°C regime, the MGT, germination rate, uniformity and seedling growth were superior at the higher 20/30°C regime. The temperature induced seed dormancy at the 20/30°C regime, could be overcome by an incubation period at lower temperatures, as fewer instances of seed dormancy were observed at the 10/20°C regime. The increase in temperature resulted in significant (P≤0.05) growth rate increases of over 650% between the 10/20°C and 20/30°C and 250% between the 10/20°C and 15/25°C night/day temperature regimes. In addition, the 20/30°C temperature treatment, although fluctuative, consistently had the highest leaf area over the entire trial period. Hardening-off of trees during the seedling stage, significantly (P≤0.05) increased the final tree height by 3.09X, 1.44X and 1.23X, compared to their non hardened-off counterparts under the 10/20°C, 15/25°C and 20/30°C temperature regimes respectively. Leaf thickness decreased by a significant (P≤0.05) 43.1% with increase in temperature between the 10/20°C and 20/30°C regime, mostly due to a thinner mesophyll layer. The efficacy of paclobutrazol on M. oleifera growth was found to be temperature dependant, reducing growth at 10/20°C, while increasing growth at both the higher 15/25°C and 20/30°C regimes. Flowering however remained unaffected by paclobutrazol. The highest instances of flowering and pollen viability were observed at the 15/25°C regime. The absence of inflorescence induction at the 20/30°C regime was responsible for the reduced flowering, signifying the necessity of vernalization prior to flowering. Even though all the results confirm the preference of M. oleifera trees towards a tropical climate, satisfactory growth with possibly improved flowering during the hot summer months in certain sub-tropical climates is achievable. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted

As giberelinas (GAs) são bem conhecidas pelo seu papel no alongamento do caule, germinação de sementes, desenvolvimento dos frutos e florescimento em plantas de dia longo. Apesar de boa parte das plantas de interesse agronômico não possuírem resposta fotoperiódica, há poucos estudos sob a possibilidade dessa classe hormonal estar envolvida em processos de florescimento e frutificação em plantas de dia neutro, como é o caso do tomateiro. O principal objetivo do trabalho foi avaliar a importância da via de indução por giberelina para o crescimento vegetativo e reprodutivo em Solanum lycopersicum cv Micro-tom (MT). Para tal, foram utilizados tratamentos exógenos com GA ou um inibidor de sua síntese, paclobutrazol (paclo), em diferentes estágios do desenvolvimento de MT. Os mutantes pro e gib3, os quais são supersensíveis e deficientes a GA, respectivamente, também foram utilizados para análises comparativas. Avaliou-se o tempo para 50% das plantas apresentarem botões florais visíveis a olho nu, tempo para antese, altura e número de entrenós na antese, número de frutos, massa média e total dos frutos e brix. O tratamento com 5 aplicações de paclo ao longo do ciclo levou a uma extensão do desenvolvimento vegetativo, com um atraso significativo na floração. No tratamento que recebeu aplicação de paclo 16 dias após semeadura, mesmo com a planta apresentando uma redução na altura, houve um restabelecimento de seu desenvolvimento reprodutivo, tornando este superior ao controle em termos de tamanho do fruto. Para o tratamento com aplicação de GA aos 16 dias, obteve-se um aumento no brix comparado ao controle. Por outro lado, o mutante procera, por possuir um crescimento vegetativo (altura e número de entrenós na antese) bem superior ao controle MT, teve seu crescimento reprodutivo prejudicado. Estes resultados nos levaram a concluir que embora GA possa induzir diretamente o florescimento e a frutificação de tomateiro, ela também pode reprimir esses processos, provavelmente deslocando o dreno para o crescimento vegetativo. Sendo assim, tanto a aplicação de GA quanto de paclo, se feitas em determinado estágio do desenvolvimento, podem melhorar a qualidade do fruto de tomateiro, aumentando o tamanho dos frutos ou o brix. / The gibberellins (GAs) are well known for their roles in stem elongation, seed germination, fruit development and flowering induction in long day plants. Despite the fact that many plants of agronomic interest do not respond to photoperiod, there are few studies about the possibility of this hormonal class to be involved in the process of flowering and fruit formation in photoperiod-insensitive plants, such as tomato. The main objective of this study was to evaluate the importance of the GA induction pathway for the vegetative and reproductive growth of Solanum lycopersicum cv Micro-Tom (MT). To accomplish this, we performed exogenous application of GA, or an inhibitor of its biosynthesis, paclobutrazol (paclo), at different stages of MT development. The mutants pro and gib3, which are hypersensitive and deficient in GA, respectively, were also used for comparative analysis. It was evaluated the time spent for 50% of plants presenting visible flower buds, the time to anthesis, plant height and the number of internodes at anthesis, number of fruits, total and individual fruit weight and fruit brix. The treatment that received five paclo applications during the life cycle presented stunted vegetative growth, which also reflected in a significant flowering delay. In the treatment that received paclo at 16th day after sowing, there was a reduction in plant height, but its reproductive development was resumed yielding fruit size superior to the control. Conversely, the treatment that received GA at 16th presented fruits with higher brix, compared to the control. Furthermore, the mutant pro, which had a vegetative growth higher than the control (in terms of plant height and number of internodes at anthesis), showed a reduced reproductive growth. These results drove us to the conclusion that although GA can directly induce flower and fruit development in tomato, it also can arrest these processes, probably redirecting the sink for vegetative growth. Thus, both GA and paclo applications, if made in a certain stage of plant development, can improve the quality of tomato fruit, increasing fruit size or brix.

Orientador: Elizabdeth Orika Ono / Banca: João Domingos Rodrigues / Banca: Sarita Leonel / Banca: Regina Celi Cavestré Coneglian / Banca: Valtemir Gonçalves Ribeiro / Resumo: A mangicultura na região semi-árida destaca-se no cenário nacional não só pela expansão da área cultivada, volume de produção, altos rendimentos e qualidade do fruto produzido, mas também pela possibilidade de produção durante todo o ano devido às condições climáticas e às tecnologias para o manejo do crescimento vegetativo e da floração, com uso da irrigação, podas e utilização de reguladores vegetais. O paclobutrazol aplicado ao solo é utilizado no manejo da produção da mangueira na maioria dos pomares. Entretanto, há a necessidade de identificar outros reguladores vegetais que ofereçam a eficiência no manejo de produção das diferentes cultivares e que possam ser aplicados via foliar, de forma a minimizar os riscos de resíduo no solo e da aplicação de quantidades inadequadas ao longo dos anos. Assim, este trabalho teve como objetivo avaliar o efeito de reguladores vegetais aplicados via foliar quanto à eficiência no manejo da floração das cultivares Tommy Atkins e Kent, com maior precisão na recomendação da dose e menores riscos de contaminação da planta e do solo, permitindo o escalonamento da produção da mangueira. Os experimentos foram conduzidos na região do Vale do Rio São Francisco, em casa de vegetação, na Embrapa SemiÁrido e em condições de campo, nas Fazendas Frutavi e Andorinhas, localizadas no município de Petrolina, PE, entre outubro de 2005 e julho de 2008. Foram avaliados três reguladores vegetais aplicados via foliar: prohexadione-Ca, etil-trinexapac e cloreto de chlormequat, em duas doses, sendo estes comparados ao paclobutrazol aplicado ao solo, em delineamento de blocos ao acaso, com quatro repetições e duas plantas por parcela. Para a comparação do efeito dos tratamentos, registraram-se dados relativos à brotação vegetativa (percentagem e comprimento dos ramos), emissão de panículas (percentagem e comprimento),...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The mango crop within the semi-arid region stands out in the national scenario due to the expansion of the planted area, the production quantity, high yields and quality of the fruit produced, as well as to the possibility of all-year production due to climatic conditions and technologies that allow the management of plant growth and blossom, through irrigation, pruning and use of plant growth regulators. Paclobutrazol applied to the soil is used for the production management of mango in most of the orchards. However, it is necessary to identify other vegetal regulators that might be efficient for the production management of different cultivars and might be applied to the leaves, so as to minimize the risk of residues in the soil and inadequate application quantities over several years. Therefore, the present paper has the purpose to evaluate the effect of plant growth regulators that can be applied to the leaves, regarding their efficiency for the blossom management of the cultivars Tommy Atkins and Kent, allowing off season mango production with higher precision in dosage recommendation and lesser contamination risk for the plant and the soil. The experiments were carried out in the area of the São Francisco river valley, under green-house conditions at Embrapa Semi-Àrido, and under field conditions on the farms Frutavi and Andorinhas, both located in the municipality of Petrolina, Pernambuco state, from October 2005 to July 2008. Three plant growth regulators, sprayed to the leaves, were evaluated: prohexadione-Ca, trinexapac-ethyl and chlomequat cloride, applied in two dosages, and compared to paclobutrazol applied to the soil, using a randomized blocks design, with four replications and two plants per plot. In order to compare the effects of the treatment, data were recorded related to vegetative growth (percentage and length of the shoots), ...(Complete abstract, click electronic access below) / Doutor

As giberelinas (GAs) são bem conhecidas pelo seu papel no alongamento do caule, germinação de sementes, desenvolvimento dos frutos e florescimento em plantas de dia longo. Apesar de boa parte das plantas de interesse agronômico não possuírem resposta fotoperiódica, há poucos estudos sob a possibilidade dessa classe hormonal estar envolvida em processos de florescimento e frutificação em plantas de dia neutro, como é o caso do tomateiro. O principal objetivo do trabalho foi avaliar a importância da via de indução por giberelina para o crescimento vegetativo e reprodutivo em Solanum lycopersicum cv Micro-tom (MT). Para tal, foram utilizados tratamentos exógenos com GA ou um inibidor de sua síntese, paclobutrazol (paclo), em diferentes estágios do desenvolvimento de MT. Os mutantes pro e gib3, os quais são supersensíveis e deficientes a GA, respectivamente, também foram utilizados para análises comparativas. Avaliou-se o tempo para 50% das plantas apresentarem botões florais visíveis a olho nu, tempo para antese, altura e número de entrenós na antese, número de frutos, massa média e total dos frutos e brix. O tratamento com 5 aplicações de paclo ao longo do ciclo levou a uma extensão do desenvolvimento vegetativo, com um atraso significativo na floração. No tratamento que recebeu aplicação de paclo 16 dias após semeadura, mesmo com a planta apresentando uma redução na altura, houve um restabelecimento de seu desenvolvimento reprodutivo, tornando este superior ao controle em termos de tamanho do fruto. Para o tratamento com aplicação de GA aos 16 dias, obteve-se um aumento no brix comparado ao controle. Por outro lado, o mutante procera, por possuir um crescimento vegetativo (altura e número de entrenós na antese) bem superior ao controle MT, teve seu crescimento reprodutivo prejudicado. Estes resultados nos levaram a concluir que embora GA possa induzir diretamente o florescimento e a frutificação de tomateiro, ela também pode reprimir esses processos, provavelmente deslocando o dreno para o crescimento vegetativo. Sendo assim, tanto a aplicação de GA quanto de paclo, se feitas em determinado estágio do desenvolvimento, podem melhorar a qualidade do fruto de tomateiro, aumentando o tamanho dos frutos ou o brix. / The gibberellins (GAs) are well known for their roles in stem elongation, seed germination, fruit development and flowering induction in long day plants. Despite the fact that many plants of agronomic interest do not respond to photoperiod, there are few studies about the possibility of this hormonal class to be involved in the process of flowering and fruit formation in photoperiod-insensitive plants, such as tomato. The main objective of this study was to evaluate the importance of the GA induction pathway for the vegetative and reproductive growth of Solanum lycopersicum cv Micro-Tom (MT). To accomplish this, we performed exogenous application of GA, or an inhibitor of its biosynthesis, paclobutrazol (paclo), at different stages of MT development. The mutants pro and gib3, which are hypersensitive and deficient in GA, respectively, were also used for comparative analysis. It was evaluated the time spent for 50% of plants presenting visible flower buds, the time to anthesis, plant height and the number of internodes at anthesis, number of fruits, total and individual fruit weight and fruit brix. The treatment that received five paclo applications during the life cycle presented stunted vegetative growth, which also reflected in a significant flowering delay. In the treatment that received paclo at 16th day after sowing, there was a reduction in plant height, but its reproductive development was resumed yielding fruit size superior to the control. Conversely, the treatment that received GA at 16th presented fruits with higher brix, compared to the control. Furthermore, the mutant pro, which had a vegetative growth higher than the control (in terms of plant height and number of internodes at anthesis), showed a reduced reproductive growth. These results drove us to the conclusion that although GA can directly induce flower and fruit development in tomato, it also can arrest these processes, probably redirecting the sink for vegetative growth. Thus, both GA and paclo applications, if made in a certain stage of plant development, can improve the quality of tomato fruit, increasing fruit size or brix.

Although mango (Mangifera indica L.) has been studied for many years, numerous problems still elude researchers. The objectives of the current trials were to study the effects of some cultural practices (fruit thinning, panicle/ bud/ renewal/ post-harvest pruning) and chemicals (Corasil.E, potassium nitrate/urea, paclobutrazol) on various vegetative, floral, yield and quality parameters. The study meant to address problems of both South African and Ethiopian mango growers. The thinning (on ‘Sensation’) and pruning (on ‘Tommy Atkins’ and ‘Keitt’) experiments were conducted for two seasons (2001-2003) at Bavaria Fruit Estate in South Africa. Effects of Paclobutrazol and Potassium nitrate were studied on ‘Tommy Atkins’ during 2002-2003 season at Upper Awash Agro-industry Enterprise in Ethiopia. Complementary effects of paclobutrazol and potassium nitrate on floral induction were studied in growth chamber experiments at the experimental farm of University of Pretoria on ‘Tommy Atkins’ and ‘Keitt’ mango. Where fruit on ‘Sensation’ were thinned to one and two fruit per panicle, a significant increase was obtained for most of the fruit quantitative parameters. The treatments where one fruit and two fruit per panicle were retained and 50% panicles removed, produced a significant increase in size of the fruit, fruit qualitative parameters and fruit retention percentage. Corasil.E produced very small sized fruit with a considerable percentage of “mules” (fruit without seed). Trees subjected to severe thinning intensities showed earlier revival of starch reserves and better vegetative growth. Applications of paclobutrazol (1- (4-chlorophenyl) –4,4-dimethyl-2- (1,2,4- triazol-1-yl) pentan-3-ol) at rates of 5.50 and 8.25 g a.i. per tree, both as a soil drench and spray applications, on ‘Tommy Atkins’ mango were effective in suppressing vegetative growth as compared to the control. Consequently, the trees from these treatments had higher total non-structural carbohydrate in their shoots before flowering which led to higher results of percentages of shoots flowering, number of panicles produced, percentages of hermaphrodite flowers, yield and quality of the fruit. Trees that received panicle pruning (during full bloom) treatment at the point of apical bud attachment, were observed to be induced for synchronized re-flowering and also attained more fruit per panicle. On the other hand, trees on which renewal pruning (early in the season) and post-harvest pruning (especially for early cultivars) treatments were applied, have been observed for the development of an adequate number of productive inflorescences. Post-harvest pruning treatments also resulted in greater vegetative growth on both cultivars. The responses to pruning treatments were greater especially in ‘Tommy Atkins’ than ‘Keitt’. The trend for the interaction of duration and chemicals in Tommy Atkins and Keitt mango cultivars revealed the possible floral induction complementary effect of PBZ after the trees were induced only for 15 days at 10/15 oC temperature. Higher potassium nitrate concentrations especially in combination with urea (5 litre solution of 4% KNO3+0.5 g urea tree-1 and 5 litres of 4% KNO3+1 g urea tree-1 ) produced higher results for most of the flowering and yield parameters in ‘Tommy Atkins’. / Thesis (DPhil (Horticulture))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted

High temperature limit successful potato cultivation in the lowlands of tropical regions. One effect of high temperature may be an increase in gibberellin activity that is inhibitory to tuberization. Paclobutrazol blocks gibberellin biosynthesis and reduces its level in the plant. The effect of paclobutrazol on potato was examined under non-inductive conditions in a greenhouse and under field conditions in the hot tropical lowlands of eastern Ethiopia. Paclobutrazol was applied as a foliar spray or soil drench at rates equivalent to 0, 2, 3, and 4 kg a. i. per ha. Paclobutrazol increased chlorophyll a and b content, and photosynthetic efficiency, enhanced early tuber initiation, delayed physiological maturity, and increased tuber fresh mass, dry matter content, specific gravity and crude protein content. It reduced the number of tubers per plant and extended the tuber dormancy period. Paclobutrazol reduced shoot growth, and plant height, and increased the partitioning of assimilates to the tubers while reducing assimilate supply to the leaves, stems, roots and stolons. Stomatal conductance and the rate of transpiration were reduced. In addition, paclobutrazol treatment increased tuber N, Ca and Fe content while reducing P, K and Mg content. Growth analyses indicated that paclobutrazol decreased leaf area index, crop growth rate, and total biomass production. It increased specific leaf weight, tuber growth rate, net assimilation rate, and partitioning coefficient (harvest index). Microscopic observations showed that leaves of treated plants developed thicker epicuticular wax layers. The epidermal, palisade and spongy mesophyll cells were larger. It increased the thickness of the cortex and the size of vascular bundles and pith cells of the stem. It also increased the width of the cortex and favoured the formation of more secondary xylem vessels, resulting in thicker roots. Deposition of starch grains in the stem pith cells, and cortical cells of the stem and root, were stimulated in response to paclobutrazol treatment. In most instances the method of application did not affect the efficiency of paclobutrazol. The effect of cultivar and reproductive growth on growth, photosynthetic efficiency, water relations, dry matter production, tuber yield and quality of potato was also the subject of investigation. Non-flowering, flowering and fruiting plants of cultivars Al-624, Al-436, CIP-388453-3(A) and CIP-388453-3(B) were evaluated under field conditions of a sub-humid tropical highland of eastern Ethiopia. Cultivars exhibited differences with respect to leaf stomatal conductance, rate of transpiration, net photosynthesis, biomass production and allocation, tuber yield, tuber size distribution, specific gravity, dry matter content and nutrient composition. Fruiting plants had higher leaf stomatal conductance, and higher rates of transpiration and photosynthesis rates. The leaf area index, tuber growth rate, and partitioning coefficient (harvest index) of the fruiting plants were reduced, but crop growth rates and net assimilation rates were higher. Without affecting total dry matter production, fruit development reduced the amount partitioned to the leaves, stems, roots, and tubers. Fruit development reduced total and marketable tuber mass and tuber numbers. The effect of MCPA and paclobutrazol were studied under greenhouse and field conditions. Single foliar sprays were applied during the early and full bud development stages at rates of 0, 250, 500, and 750 g a.i. ha-1. Both MCPA and paclobutrazol greatly reduced the number of flowers and completely inhibited berry set. MCPA did not affect the number, yield, dry matter content and specific gravity of tubers. Without affecting the number of tubers, paclobutrazol increased tuber yield, dry matter content and specific gravity. / Thesis (DPhil (Horticultural Science))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted