Orientador : William Henry Stubblebine / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-07-15T06:04:34Z (GMT). No. of bitstreams: 1 Santos_FlavioAntonioMaesdos_M.pdf: 9699526 bytes, checksum: 16cb0c5e1cf13b544e21260cee6607d1 (MD5) Previous issue date: 1983 / Resumo: Devido a sua importância na agricultura, plantas invasoras têm sido objeto de muitas pesquisas, sendo a maior parte voltada para a descoberta de métodos para o seu controle. A despeito disso, devido a sua grande disponibilidade, rápido desenvolvimento e rápida e fácil reprodução, são importantes em estudos de adaptação e evolução. Por ser uma planta bastante comum na região, sendo invasora de pastagens e lavouras e constituindo-se num grande problema em culturas de algodão, Acanthospermum hispidum DC. (Compositae) foi escolhida para o desenvolvimento deste estudo. Dados foram obtidos em 4 áreas na região de Campinas, SP, com os objetivos de: (1) descrever os padrões biológicos básicos de A. hispidum, uma planta invasora (comportamento de sementes, sistema de reprodução, alocação de recursos); (2) quantificar aspectos de dinâmica populacional desta espécie, que possam fornecer subsídios para o seu controle; e (3) proporcionar bases gerais para uma melhor compreensão das estratégias adaptativas de plantas invasoras na Região Neotropical. Os resultados indicaram que; (1) sementes de A. hispidum são fotoblásticas positivas; (2) a variação de temperatura parece seu um fator importante na germinação; (3) temperaturas baixas parecem induzir a dormência, enquanto que temperaturas muito altas levam à morte das sementes; (4) existem ciclos bem marcantes no comportamento de germinação em todas as populações de sementes, com picos de germinação deslocados para certas épocas do ano, independente de quando as sementes foram produzidas... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Because of their importance in agriculture, weeds have been the subject of much research mainly in order ro discover new control methods. In addition, they are readily available, grow quickly and reproduce abundantly and early, making them ideal material for studies of evolution and adaptation. Acanthosérmum hispidum DC. (Compositae) was selected for this study as it is a common plant in this region, being a weed of pastures and cultivated areas, especially in cotton plantations. Data were obtained from 4 areas in the region of Campinas, SP, in order to: (1) describe basic biological paters of A. hispidum (seed behavior, reproductive system, resource allocation); (2) quantify aspects of the populational dynamics of this species, which could contribute to its control; and (3) provide a general basis for a better understanding of the adaptive strategies of weeds in the Neotropical Region. The results indicate: (1) A. hispidum has positively photoblastic seeds; (2) temperature variation seems to be an important factor in seed germination; (3) low temperature kills the seeds; (4) the germination behavior has well defined cycles in all seed populations, with peaks of germinations occurring in certain periods of the year, independently of when the seed were produced; (5) it is probable that there is a mechanism of internal control, which reduces the probability of seed germination during some periods of the year, even under favorable conditions... Note: The complete abstract is available with the full electronic digital thesis or dissertations / Mestrado / Mestre em Ecologia

Competition studies with soybeans, Glycine max (L.) Merr. "Bragg." and sicklepod, Cassia obtusifolia L., were conducted at the Agricultural Research and Education Center of the University of Florida in Quincy, Florida. Two field experiments were established, one on May 22, 1975. and the other four weeks later, on June 19, 1975, to determine the competitive effects of various sicklepod densities and the influences of soybean row distances on weed dry matter, soybear plant characteristics, yield components and seed yield, and on soil nutrient content. Control, low, medium, and high sicklepod densities in the first experiment were O, 25,000, 53,000, and 77,000 p1ants/ha, respectively; while the second experiment presented control, low, medium, and high sicklepod densities of O, 36,000, 68,000, and 122,000 plants/ha, respectively. Three soybean row distance treatments were tested using a constant pattern of 90-, 60-, and 45-cm widths throughout the growing season. Three other treatments, evaluated in a variable patern, were initially seeded in 30-cm row widths. Five weeks after planting, an appropriate number of soybean rows were harvested from the 30"cm pattern to establish row distances of 90, 60, and 30-60 cm for the remainder of the season. ln the greenhouse a test was conducted to evaluate the effects af those variables on seed germination and seedling vigor for the next soybean generation. As a result of full-season sicklepod competition, soybean plants were less branched, set fewer leaves, and presented thinner stems as compared to the control. However, height of soybean plants was not affected by the presence of sicklepod. ln one of the two experiments, number of nodes decreased for soybeans under weed campetition. The yield components--number of pods; number of seeds, and seed yield per soybean plant--were all similarly reduced due to weed competition. Seeds per pod were decreased to a lesser extent. Soybean seed yields per unit area were significantly diminished by increasing levels af sicklepod ínfestation. While the control produced 3120 kg/ha, the sicklepod densities of 25,000, 53,000, and 77,000 plants/ha reduced seed yíelds 47, 65, and 73%, respectively. As soybean row distances decreased, number of branches, number of leaves, and stem diameter of soybeans decreased. However, the height of soybean plants increased with narrwing of row width. The components of seed yield--number of pods, number of seeds, and seed yield per soybean plant--diminished as row spacing was reduced. Maximum difference between row distances for these attributes was attained for soybean plants under weed-free conditions. Generally, as row width decreased, soybean seed yield per unit area increased. Specifically, soybear.s in 90-cm rows, either in constant or variable row pattern, yielded less than soybeans in 60- and 30-60-cm rows in the variable pattern. Soil contents of phosphorus, potassium, calcium, and magnesium were not affected by the various levels of sicklepod and soybean populalions. Neither the sicklepod densities nor the soybean row distances influenced seed germination and seedling vigor in the next soybean generation. Sicklepod was a strong competitor with soybeans at all density ranges investigated. Because sicklepod grows taller than soybeans during the reproductive stages of the crop, limited success can be reached by varying row spacing alone. However, this practice is considered an integral measure to complement other methods of sicklepod control. Compared to constant rows, the soybean cropping system using variable row spacings presents the choice of planting soybeans at close row spacings to provide early competition with weeds and the possibility of obtaining a forage crop after the first month of growth, without any decreases on the final seed yields.

Competition studies with soybeans, Glycine max (L.) Merr. "Bragg." and sicklepod, Cassia obtusifolia L., were conducted at the Agricultural Research and Education Center of the University of Florida in Quincy, Florida. Two field experiments were established, one on May 22, 1975. and the other four weeks later, on June 19, 1975, to determine the competitive effects of various sicklepod densities and the influences of soybean row distances on weed dry matter, soybear plant characteristics, yield components and seed yield, and on soil nutrient content. Control, low, medium, and high sicklepod densities in the first experiment were O, 25,000, 53,000, and 77,000 p1ants/ha, respectively; while the second experiment presented control, low, medium, and high sicklepod densities of O, 36,000, 68,000, and 122,000 plants/ha, respectively. Three soybean row distance treatments were tested using a constant pattern of 90-, 60-, and 45-cm widths throughout the growing season. Three other treatments, evaluated in a variable patern, were initially seeded in 30-cm row widths. Five weeks after planting, an appropriate number of soybean rows were harvested from the 30"cm pattern to establish row distances of 90, 60, and 30-60 cm for the remainder of the season. ln the greenhouse a test was conducted to evaluate the effects af those variables on seed germination and seedling vigor for the next soybean generation. As a result of full-season sicklepod competition, soybean plants were less branched, set fewer leaves, and presented thinner stems as compared to the control. However, height of soybean plants was not affected by the presence of sicklepod. ln one of the two experiments, number of nodes decreased for soybeans under weed campetition. The yield components--number of pods; number of seeds, and seed yield per soybean plant--were all similarly reduced due to weed competition. Seeds per pod were decreased to a lesser extent. Soybean seed yields per unit area were significantly diminished by increasing levels af sicklepod ínfestation. While the control produced 3120 kg/ha, the sicklepod densities of 25,000, 53,000, and 77,000 plants/ha reduced seed yíelds 47, 65, and 73%, respectively. As soybean row distances decreased, number of branches, number of leaves, and stem diameter of soybeans decreased. However, the height of soybean plants increased with narrwing of row width. The components of seed yield--number of pods, number of seeds, and seed yield per soybean plant--diminished as row spacing was reduced. Maximum difference between row distances for these attributes was attained for soybean plants under weed-free conditions. Generally, as row width decreased, soybean seed yield per unit area increased. Specifically, soybear.s in 90-cm rows, either in constant or variable row pattern, yielded less than soybeans in 60- and 30-60-cm rows in the variable pattern. Soil contents of phosphorus, potassium, calcium, and magnesium were not affected by the various levels of sicklepod and soybean populalions. Neither the sicklepod densities nor the soybean row distances influenced seed germination and seedling vigor in the next soybean generation. Sicklepod was a strong competitor with soybeans at all density ranges investigated. Because sicklepod grows taller than soybeans during the reproductive stages of the crop, limited success can be reached by varying row spacing alone. However, this practice is considered an integral measure to complement other methods of sicklepod control. Compared to constant rows, the soybean cropping system using variable row spacings presents the choice of planting soybeans at close row spacings to provide early competition with weeds and the possibility of obtaining a forage crop after the first month of growth, without any decreases on the final seed yields.

Competition studies with soybeans, Glycine max (L.) Merr. "Bragg." and sicklepod, Cassia obtusifolia L., were conducted at the Agricultural Research and Education Center of the University of Florida in Quincy, Florida. Two field experiments were established, one on May 22, 1975. and the other four weeks later, on June 19, 1975, to determine the competitive effects of various sicklepod densities and the influences of soybean row distances on weed dry matter, soybear plant characteristics, yield components and seed yield, and on soil nutrient content. Control, low, medium, and high sicklepod densities in the first experiment were O, 25,000, 53,000, and 77,000 p1ants/ha, respectively; while the second experiment presented control, low, medium, and high sicklepod densities of O, 36,000, 68,000, and 122,000 plants/ha, respectively. Three soybean row distance treatments were tested using a constant pattern of 90-, 60-, and 45-cm widths throughout the growing season. Three other treatments, evaluated in a variable patern, were initially seeded in 30-cm row widths. Five weeks after planting, an appropriate number of soybean rows were harvested from the 30"cm pattern to establish row distances of 90, 60, and 30-60 cm for the remainder of the season. ln the greenhouse a test was conducted to evaluate the effects af those variables on seed germination and seedling vigor for the next soybean generation. As a result of full-season sicklepod competition, soybean plants were less branched, set fewer leaves, and presented thinner stems as compared to the control. However, height of soybean plants was not affected by the presence of sicklepod. ln one of the two experiments, number of nodes decreased for soybeans under weed campetition. The yield components--number of pods; number of seeds, and seed yield per soybean plant--were all similarly reduced due to weed competition. Seeds per pod were decreased to a lesser extent. Soybean seed yields per unit area were significantly diminished by increasing levels af sicklepod ínfestation. While the control produced 3120 kg/ha, the sicklepod densities of 25,000, 53,000, and 77,000 plants/ha reduced seed yíelds 47, 65, and 73%, respectively. As soybean row distances decreased, number of branches, number of leaves, and stem diameter of soybeans decreased. However, the height of soybean plants increased with narrwing of row width. The components of seed yield--number of pods, number of seeds, and seed yield per soybean plant--diminished as row spacing was reduced. Maximum difference between row distances for these attributes was attained for soybean plants under weed-free conditions. Generally, as row width decreased, soybean seed yield per unit area increased. Specifically, soybear.s in 90-cm rows, either in constant or variable row pattern, yielded less than soybeans in 60- and 30-60-cm rows in the variable pattern. Soil contents of phosphorus, potassium, calcium, and magnesium were not affected by the various levels of sicklepod and soybean populalions. Neither the sicklepod densities nor the soybean row distances influenced seed germination and seedling vigor in the next soybean generation. Sicklepod was a strong competitor with soybeans at all density ranges investigated. Because sicklepod grows taller than soybeans during the reproductive stages of the crop, limited success can be reached by varying row spacing alone. However, this practice is considered an integral measure to complement other methods of sicklepod control. Compared to constant rows, the soybean cropping system using variable row spacings presents the choice of planting soybeans at close row spacings to provide early competition with weeds and the possibility of obtaining a forage crop after the first month of growth, without any decreases on the final seed yields.

Orientador: Marcelo da Costa Ferreira / Coorientador: Rafael Gomes Viana / Banca: Rone Batista de Oliveira / Banca; Mariluce Pascoina Nepomuceno / Resumo: O espalhamento das gotas sobre superfícies vegetais pode indicar eficiência na aplicação de herbicidas. Porém, o espalhamento de uma gota depende das características da calda fitossanitária, especificamente das propriedades físico-químicas e as suas interações com as superfícies onde as gotas se depositam. As propriedades físicas, como tensão superficial e ângulo de contato podem ser alteradas pela adição de adjuvantes ao tanque do pulverizador. Assim, o desenvolvimento de pesquisas que avaliem a interação dos herbicidas associados a adjuvantes é importante para a recomendação correta do adjuvante, uma vez que o adjuvante pode proporcionar maior espalhamento da gota sobre a superfície de diferentes espécies de plantas, e potencializar o controle. Nesse sentido foram realizados dois estudos, sendo o primeiro para avaliar a tensão superficial e o ângulo de contato em três espécies do gênero Sida. No segundo foi avaliado o ângulo de contato de seis espécies de plantas daninhas e a relação do ângulo com o controle de Lantana camara e Crotalaria incana, de ocorrência em pastagem, ambiente vastamente cultivado no Brasil, mas no qual são raros os trabalhos desta natureza. Concluiu-se que a adição do adjuvante lecitina ao herbicida aminopiralide + fluroxipir reduz o ângulo de contato das gotas sobre as superfícies adaxial e abaxial de Sida cordifolia e Sida glaziovii. E quanto menor ângulo de contato maior controle das espécies avaliadas. / Abstract: The spreading of the drops on plant surfaces may indicate the possible success in herbicide application. However, the spread of a drop depends on the characteristics of the spray solution, specifically the physicochemical properties and their interactions with the surfaces where the drops settle. Physical properties such as surface tension and contact angle can be altered by the addition of adjuvants to the spray tank. Thus, the development of research that evaluates the interaction of herbicides associated with adjuvants is important for the correct recommendation of the adjuvant, since the adjuvant can provide greater spreading of the drop on the surface of different species of plants, and potentiate the control. In this sense two studies were carried out, being the first to evaluate the surface tension and the contact angle in three species of the Sida genus. In the second, was evaluated the contact angle of six weed species and the angle relationship with the control of Lantana camara and Crotalaria incana, a pasture, an area widely cultivated in Brazil, but in which works of this nature are rare. It was concluded that the addition of the lecithin adjuvant to the aminopyralid herbicide + fluroxypyr reduces the contact angle of the drops on the adaxial and abaxial surfaces of Sida cordifolia and Sida glaziovii. And the lower the contact angle the greater the control of the evaluated species. / Mestre

Made available in DSpace on 2014-06-11T19:22:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-22Bitstream added on 2014-06-13T18:07:55Z : No. of bitstreams: 1 souza_gsf_me_botfca.pdf: 3983066 bytes, checksum: 0ecc95aedf49bb3a0b687a39cac24ced (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo do presente trabalho foi avaliar a influência de diferentes intervalos de chuva na eficiência de herbicidas aplicados em pós-emergência em quatro espécies de plantas daninhas: Ipomoea grandifolia, Senna obtusifolia, Brachiaria decumbens e Brachiaria plantaginea. O experimento foi conduzido em condições de casa-de-vegetação com uma planta por vaso, com capacidade de 2,5 L. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições, disposto em um esquema fatorial 7x8 (sete tratamentos químicos e oito intervalos de chuva) para as espécies dicotiledôneas e 6x8 (seis tratamentos herbicidas e oito intervalos de chuva) para as monocotiledôneas. Os tratamentos testados foram: glyphosate em cinco formulações comerciais (Roundup Original, Roundup WG, Roundup Transorb, Roundup Transorb R e Roundup Ultra) a 1.080 g e.a. ha-1, amonio-glufosinate a 400 g i.a. ha-1 e, apenas para as espécies dicotiledôneas utilizou-se o tratamento com 2,4-D a 1.000 g e.a. ha-1. A simulação de chuva de 20 mm foi realizada em oito intervalos de tempo após a aplicação dos herbicidas (15‟, 30‟, 1h, 2h, 4h, 6h, 8h e sem chuva). Foram realizadas avaliações visuais de controle das plantas aos 3, 7, 14, 21, 28 e 35 dias após a aplicação (DAA) para I. grandifolia,aos 3, 7, 14, 21 e 28 DAA para S. obtusifolia, aos 3, 7, 14 e 21 DAA para B. decumbens e aos 3, 7 e 14 DAA para B. plantaginea. Ao final do período de avaliação de cada espécie determinou-se a massa seca das plantas. Os resultados foram submetidos à análise de variância pelo Teste “F” e as médias dos tratamentos comparadas pelo teste de Tukey a 5% de probabilidade. Para plantas de I. grandifolia a ocorrência de chuvas após 15 minutos da aplicação do herbicida 2,4-D não afetou sua eficiência de controle, já os herbicidas amonio-glufosinate e glyphosate, em todas suas... / The aim of this study was to evaluate the influence of different intervals of rain in the efficiency of herbicides applied post-emergence in four weed species: Ipomoea grandifolia, Senna obtusifolia, Brachiaria decumbens and Brachiaria plantaginea. The experiment was conducted in conditions of green-house with one plant per pot, with a capacity of 2.5 L. The experiment was a completely randomized design with four replications, arranged in a 7x8 factorial arrangement (seven chemical treatments and eight intervals of rain) for dicotyledons and 6x8 (six and eight herbicide treatments rain intervals) for monocotyledons. The treatments were: glyphosate in five formulations (Roundup Original, Roundup WG, Transorb Roundup, Roundup and Roundup Ultra Transorb R) to 1080 g ae ha-1 ammonium-glufosinate at 400 g ai ha-1, and only for dicot species, we used treatment with 2,4-D and 1,000 g ha-1. The simulated rainfall of 20 mm was accomplished in eight intervals of time after herbicide application (15', 30', 1h, 2h, 4h, 6h, 8h and no rain). Visual evaluations of weed control at 3, 7, 14, 21, 28 and 35 days after application (DAA) for I. grandifolia, 3, 7, 14, 21 and 28 DAA for S. obtusifolia, 3, 7, 14 and 21 DAA for B. decumbens and at 3, 7 and 14 DAA for B. plantaginea. At the end of the trial period of each species determined the dry mass of plants. The results were subjected to analysis of variance test by F and the means were compared by Tukey test at 5% probability. For plants I. grandifolia to rainfall after 15 minutes of application of 2,4-D did not affect the efficiency of control because the herbicides glufosinate and glyphosate-ammonium, in all its formulations tested showed reduced efficiency of control when the occurrence of rainfall up to 8 hours after herbicide application and, with the exception of Roundup Original, all herbicides provided greater than 50% reductions in dry mass of ... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:22:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-18Bitstream added on 2014-06-13T19:48:23Z : No. of bitstreams: 1 castro_rm_me_botfca.pdf: 7107653 bytes, checksum: 61a50230ec66c506c741fa342395e15d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Clicar acesso eletrônico abaixo.

Made available in DSpace on 2014-06-11T19:22:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-18Bitstream added on 2014-06-13T19:07:31Z : No. of bitstreams: 1 silva_fml_me_botfca.pdf: 7467209 bytes, checksum: 3b7833c036cd2436cdc7636a5037a049 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Em cana-de-açúcar, a colheita sem queimada deixa sobre o solo uma espessa camada de palha que pode superar 20 toneladas por hectare e que intercepta grande parte do herbicida aplicado em pré-emergência, impedindo que este chegue até o solo onde irá atuar. Objetivou-se com este trabalho avaliar a eficácia do mesotrione aplicado em pré-emergência sobre palha de cana-de-açúcar em diferentes quantidades, períodos e intensidades de chuvas após a aplicação no controle de plantas daninhas. Para isso foram conduzidos 4 experimentos em casa-devegetação e um em campo. Os experimentos em casa-de-vegetação objetivaram avaliar a eficácia do herbicida mesotrione, com simulação de diferentes intervalos de chuva após a aplicação do herbicida, em associação com palha da cana-de-açúcar, sobre diferentes quantidades de palha e estimar a absorção foliar do herbicida mesotrione através do contato direto de plantas daninhas com a palha de cana-de-açúcar. O experimento conduzido em condições de campo objetivou avaliar a eficácia do herbicida mesotrione aplicado sobre diferentes quantidades de palha em comparação com o padrão de mercado hexazinone+diuron, no controle de quatro espécies de plantas daninhas (Brachiaria decumbens, Ipomoea grandifolia, Euphorbia heterophylla e Panicum maximum). Os resultados mostraram que o mesotrione controlou em pré-emergência E. heterophylla, I. grandifolia, Digitaria horizontalis, Sida rhombifolia e Commelina benghalensis, sendo os melhores resultados obtidos com o herbicida aplicado sobre a palha ou sobre o solo, porém, com subseqüente simulação de chuva. O controle das plantas daninhas por meio de absorção do herbicida pelo contato direto com a palha impregnada com o princípio ativo foi considerado satisfatório, com resultados de controle acima de 95%, chegando a 100 %, para a I. grandifolia, com simulação de orvalho; enquanto... / In sugar cane, harvesting without burning leaves on the ground a thick layer of straw that can exceed 20 tons per hectare which intercepts the herbicide applied pre-emergence, preventing it from reaching the soil where they will act . The objective of this work was to evaluate the efficacy of mesotrione applied pre-emergence on sugar cane straw in different amounts, periods and intensities of rainfall after application to control weeds. For this four experiments were conducted in greenhouse and one in field. The experiments in greenhouse aimed to evaluate the efficacy of the herbicide mesotrione, simulating different periods of rain after herbicide application, in combination with sugar cane straw, on different amounts of straw and to estimate the foliar uptake of the herbicide mesotrione through direct contact of weeds with the sugar cane straw. The experiment conducted under field conditions aimed to evaluate the efficacy of the herbicide mesotrione applied on different amounts of straw compared with the standard hexazinone+diuron for the control of four weed species (Brachiaria decumbens, Ipomoea grandifolia, Euphorbia heterophylla and Panicum maximum). The results showed that mesotrione controlled in pre-emergence E. heterophylla, I. grandifolia, Digitaria horizontalis, Sida rhombifolia and Commelina benghalensis, and the best results obtained with the herbicide applied on the straw or on the ground, but with subsequent rainfall simulation. The weed control through herbicide absorption by direct contact with the straw impregnated with the active principle was considered satisfactory, with results of controlled over 95% to 100% for I. grandifolia, with simulated dew, while E. heterophylla was not controlled by the herbicide. The weed control with the occurrence of rain 1 DAA showed the best results for the herbicide mesotrione than rain at 14 DAA, while for imazapic and hexazinone+diuron...(Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:22:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-17Bitstream added on 2014-06-13T19:07:34Z : No. of bitstreams: 1 araldi_r_me_botfca.pdf: 1046717 bytes, checksum: 963e0ad0fa13ae2bb75dff1726503432 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Para que ocorra o efetivo controle de plantas daninhas é preciso que o herbicida além de ser absorvido, translocado e redistribuído pelas plantas, chegue até o sítio de ação em quantidade suficiente para ser fitotóxico, ou seja, uma vez presente na célula, interfira nos processos vitais específicos da planta daninha. Como o amicarbazone é um herbicida inibidor da fotossíntese torna-se necessário que alcance os cloroplastos das células das folhas para atuar em seu sítio de ligação no fotossistema II. Como conseqüência da interrupção do transporte de elétrons no fotossistema II ocorre um incremento na fluorescência produzida, além da formação de radicais livres que levam a planta à morte. Ainda para o sucesso no controle químico de plantas daninhas na produção da cana-de-açúcar é importante a seletividade da cultura aos herbicidas. Há cultivares que apresentam respostas diferenciadas aos herbicidas, tendo como conseqüências freqüentes, problemas de fitotoxicidade, podendo ocasionar redução na produtividade do canavial para as cultivares mais sensíveis. Dessa forma, o objetivo deste trabalho foi avaliar a absorção e intoxicação de plantas daninhas e diferentes cultivares de cana-de-açúcar submetidas ao amicarbazone. O trabalho foi desenvolvido em quatro experimentos, sendo que o primeiro foi a verificação do consumo de água através da pesagem diária para Digitaria horizonthalis, Panicum maximum Jacq., Ipomoea grandifolia (Dammer) O’Donell, Ipomoea hederifolia L. e Brachiaria decumbens Stapf. e para as cultivares de cana-de-açúcar PO8862, SP80 3280 e RB83 5486, caracterizadas como sensível, intermediária e tolerante ao amicarbazone respectivamente. No segundo experimento foi quantificada a concentração do amicarbazone, imazapic, tebuthiuron e hexazinone em seiva de xilema das três cultivares de cana-de-açúcar e da Ipomoea grandifolia... / To allow for the effective control of weeds, it is necessary that the herbicide can be absorbed, translocated and redistributed to the plant reaches its site of action in sufficient quantity to be phytotoxic, i.e. once present in the cell, interfere with vital processes specific to the weed. How amicarbazone is a photosynthesis inhibitor herbicide is needed to reach the chloroplasts of leaf cells to act in its binding site in photosystem II. As a consequence of the interruption of electron transport in photosystem II is an increase in fluorescence produced, besides the formation of free radicals that lead to plant death. Even for success in the chemical control of weeds in the production of sugarcane is important to selectivity of culture to herbicides. There are cultivars that exhibit differential responses to herbicides, and, as a consequence frequent problems of phytotoxicity, getting to lead to reduced productivity of sugarcane cultivars to the most sensitive. Thus, the objective was to evaluate the absorption and toxicity of weeds and cultivars of sugarcane subject to amicarbazone. The study was conducted in four experiments, and the first was to check the consumption of water through the daily weights for Digitaria horizonthalis,Panicum maximum, Ipomoea grandifolia, Ipomoea hederifolia and Brachiaria decumbens and for the varieties of sugarcane PO8862, SP80 3280 and RB83 5486, characterized as sensitive, tolerant and intermediate amicarbazone respectively. The second experiment measured the concentration of amicarbazone, imazapic tebuthiuron and hexazinone in xylem sap of the three varieties of cane sugar and Ipomoea grandifolia through Schollander pump and the chromatography and mass spectrometry (LC-MS) to extraction and quantification of compounds respectively. The third experiment was compared to the electron transport rate (ETR) with the concentration of amicarbazone absorbed... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:22:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-02Bitstream added on 2014-06-13T20:09:15Z : No. of bitstreams: 1 campos_cf_me_botfca.pdf: 502483 bytes, checksum: ecf5c163076e65ba5973a74e8b1df1f8 (MD5) / A interferência de plantas daninhas com a cultura do milho pode refletir em perdas relevantes na produtividade de grãos. Em ecossistemas agrícolas, a cultura e as plantas daninhas possuem suas demandas por água, luz, nutrientes e, na maioria das vezes, um ou mais desses fatores de crescimento estão disponíveis em quantidade insuficiente até mesmo para o próprio desenvolvimento da cultura, o que estabelece, assim, a Interferência. O objetivo desse trabalho foi determinar o Período Anterior à Interferência (PAI), o Período Crítico de Prevenção à Interferência (PCPI) e o Período Total de Prevenção à interferência (PTPI) de plantas de capim-colchão (Digitaria nuda) na cultura do milho no município de Botucatu/SP, em dois períodos de semeadura, safra e safrinha. Os tratamentos foram divididos em duas modalidades: períodos de convivência da cultura com as plantas infestantes e períodos em que a cultura permaneceu livre da presença da comunidade infestante, sendo estes de 7, 14, 21, 28, 35, 42, 49 e 56 dias, além de uma testemunha com controle de plantas daninhas até o fim do ciclo da cultura e outra com convivência das plantas daninhas até a colheita. A origem das plantas de capim-colchão foi do banco de sementes, garantido pelo conhecimento do histórico da área experimental. Para determinação dos períodos de interferência quanto ao rendimento de grãos, foi realizada a análise de regressão não linear. Determinou-se também a altura de plantas, altura da inserção da espiga, comprimento das espigas, número de grãos por fileiras, número de fileiras e peso de 100 sementes. Os dados obtidos foram submetidos à análise de variância pelo teste F, sendo as médias dos tratamentos comparadas pelo teste Tukey... / The interference between weeds and corn can reflect significant losses in grain yield. In agricultural ecosystems, crop and weeds have their demands for water, light and nutrients and, in most cases, one or more of these growth factors are not available in sufficient quantity even for the crop development, thereby establishing competition. The aim of this study was to determine the Period Before Interference (PBI), the Critical Period of Interference Prevention (CPIP) and Total Period of Interference Prevention (TPIP) of the crabgrass plant (Digitaria nuda) into corn in Botucatu/SP, in two periods of sowing, in season and out of season. The treatments were set up into two categories: coexistence periods between crop and weeds, and weed free periods. The periods consisted of 7, 14, 21, 28, 35, 42, 49 and 56 days, a weed control and a no weed control treatment during whole crop cycle. The source of the crabgrass was from soil seed bank as confirmed by the area’s known history. To determine the periods of interference on the yield, a nonlinear regression analysis was performed. Plant height, ear insertion height, ear length, number of grains per row, row number and 100 seeds weight ware also analyzed. The data were subjected to variance analysis by the F test, and treatment averages were compared by the Tukey test at 5% probability. For the crop studied 5% yield loss was considered acceptable, in first season conditions the period before interference was 22 days after emergence (DAE) and the total period of interference prevention was 54 DAE, the Critical Period of Interference Prevention was 29 days. For second season the period before interference and the total period of interference prevention were 23 and 26 DAE, respectively and the Critical Period of Interference Prevention was 29 days was 2 days.