Andréia da Silva Almeida

BIOATIVADOR NO DESEMPENHO FISIOLÓGICO DE SEMENTES DE ARROZ

Rice is one of the most important and traditional cereal crops grown as it is a staple food of most of the world population. Rio Grande do Sul state is an important rice producer, accounting for 50% of Brazilian production, 80% of which is irrigated rice. The systemic insecticide thiamethoxam is transported within the plant and can activate various physiological processes, such as protein expression. These proteins interact with stress defense

Resposta fisiológica de sementes de algodão tratadas com tiametoxam sob estresse térmico

This study aimed to verify the effect of seeds treated with thiamethoxam on the emergence, growth and chlorophyll content of seedlings of two cotton cultivars subjected to abiotic stress. The seeds used were from the DeltaOpal and NuOpal cultivars, each one represented by three lots, previously subjected to determination of moisture content, germination and vigor (low temperature germination). Then, the seeds from each lot, treated with thiamethoxam at a dose of 600 mL of product per 100 kg-1 seed or not, were exposed to temperature (18, 25 and 35 °C) and water availability (40, 60 and 80%) stress conditions. The emergence percentage, the root and shoot length, and the chlorophyll content were evaluated. The growth of cotton seedlings from the DeltaOpal and NuOpal cultivars, subjected to low temperature conditions and water availability of 40 to 60%, is favored by seed treatment with thiamethoxam. Seed treatment with thiamethoxam increases chlorophyll content during the development of cotton plants.

Thiamethoxam: An Inseticide that Improve Seed Rice Germination at Low Temperature

Researches were made to establish the activity of the active ingredient on the physiology of the plant, when applied the soybean seed treatment. It was observed that seed germination index and seedling vigor were higher than those of plants in plots without seed treatment. It was also found that, under water stress conditions soybean plants from seed treated with thiamethoxam showed better growth, such as increased length and root volume, faster ini‐ tial development, higher leaf area, height, number of pods and green colored more intense.

Response of wheat seeds to zinc application during storage

Seed coating is among the most potentially beneficial treatments to enhance seed performance, contributing to the improvement of crop stands due to its role in improved seedling development. Thus, micronutrients such as zinc exhibit potential for use in seed coatings. The objective of this research is to evaluate the effect of coating wheat seeds with zinc sulfate on traits that are related to seed quality during storage and nutrition efficiency during seedling growth. The levels of ZnSO 4 used were 0, 1, 2, 3 and 4 mL kg -1 seed. After 0, 3 and 6 months of storage, the germination percentage, mean root length, root dry mass, seedling emergence, nutritional efficiency (absorption, transport and use) and zinc content in the seeds were evaluated. Seed coating with ZnSO 4 increased seedling dry weight and zinc content in roots, which are the primary sink for this nutrient. Higher rates of ZnSO 4 coating resulted in higher absorption efficiency and a concomitant decrease in Zn transport and use efficiency. Thus, the application of appropriate doses of zinc to seeds increases the accumulation of this nutrient, resulting in well-nourished plants that present improved initial development under adverse conditions. Recubrimiento de semillas es uno de los tratamientos potencialmente mas beneficioso para mejorar el rendimiento de la semilla. Tambien contribuye a proporcionar a los productores con mejores puestos de cultivos derivados de un mejor desarrollo de la plantula, que destaca la posibilidad de uso de micronutrientes como el zinc para el recubrimiento de semillas. El objetivo de esta investigacion es evaluar el efecto del recubrimiento de semillas de trigo con sulfato de zinc, en las caracteristicas relacionados con la calidad de la semilla durante el almacenamiento y la eficiencia nutricional de respuesta durante el crecimiento de plantulas. Las semillas fueron tratadas con 0, 1, 2, 3 y 4 mL de ZnSO 4 por kg de semillas. Despues de un periodo de 0, 3 y 6 meses de almacenamiento fueron evaluados porcentaje de germinacion, la longitud media de la raiz, materia seca de la raiz, la emergencia de plantulas, eficiencia nutricional (absorcion, transporte y uso) y el contenido de zinc en las semillas. Recubrimiento de semillas con ZnSO 4 aumento materia seca de plantulas y el contenido de zinc en las raices. Por lo tanto, con los resultados obtenidos en este estudio, se observo que la aplicacion de dosis apropiadas de zinc en las semillas proporciona una acumulacion de este nutriente que se traduce en una planta bien alimentada, que presentan un mejor desarrollo inicial en condiciones adversas.

Insecticide Thiamethoxam: A Bioactive Action on Carrot Seeds (Daucus carota L.)

Explorations of the substances potential that can act as promoters of growth-inducing activities are in substantial contribution of research to agriculture. Many of these activities are related to the activation capacity of the plants resistance mechanisms, thus enabling seek control through integrated management. With the modernization of agriculture, marked advances in farming techniques have been obtained, allowing mitigate the limiting factors with weather conditions such diseases, pests, among others. The plant physiology has promoted great advances in recent years with the advent of modern techniques such as the production of plants by tissue culture, genetic engineering and biotechnology. Among these modern techniques, the use of bioactive, capable of increasing the productive potential of plants, is an increasing use in the practice of modern agriculture and widespread in countries highly technical. In Brazil, the use of bioactive beginning to be explored and the results of several studies have shown that these substances provide significant increases in productivity and, in quality, as observed, for example, significant increases in the amount of larger fruits. Bioactivators are natural substances of plant origin that have actions similar to the main plant growth regulators, aimed at growth and development of the plant. Provide better physiological balance, favoring closer ties to the genetic potential of culture. Moreover, they are complex organic substances, not bioregulators, growth modifiers, capable of working in the plant transcription factors and gene expression in membrane proteins by altering the ion transport. They also act in metabolic enzymes could affect the secondary metabolism and may alter the mineral nutrition, induce the production of precursors of plant hormones, leading to hormone synthesis and more intense response to nutrients and plant hormones. Applied to plants, bioactivators cause modification or alteration of specific metabolic and physiological processes, such as increasing the division and cell elongation, stimulation of chlorophyll synthesis and photosynthesis, flower bud differentiation, increasing the life of plants, softening the effects of adverse weather conditions and increasing the absorption of nutrients and setting their roots.

Envelhecimento acelerado e ocorrência de fungos para avaliação do potencial fisiológico de sementes de arroz

O teste de envelhecimento acelerado e um dos mais difundidos para a avaliacao do vigor das sementes de varias especies cultivadas, sendo capaz de proporcionar informacoes com alto grau de consistencia. No entanto, o desempenho das sementes envelhecidas artificialmente pode ser influenciado, de modo negativo, pela presenca de fungos. Diante disso, o presente trabalho teve por objetivo estudar o teste de envelhecimento acelerado em diferentes concentracoes salinas para determinar o potencial fisiologico e sanitario de cultivares de arroz. Foram utilizadas sementes de arroz das cultivares Irga 409, Irga 424 e Epagri 144. O teste de envelhecimento acelerado foi conduzido em tres etapas: teste tradicional com uso de agua; teste com uso de solucoesde NaCl saturada (SS) e super saturada (SSS) durante os periodos de 24, 48, 72 e 96 horas a 42 °C. Apos, foi avaliado o grau de humidade, a germinacao e a sanidade das sementes. Os efeitos deleterios do teste de envelhecimento acelerado foram atenuados com o incremento de concentracoes salinas. O teste de envelhecimento acelerado em SS as 48 h e em SSS as 48, 72 e 96 h permite classificar as cultivares de arroz em diferentes niveis de vigor. Sementes contaminadas por agentes fungicos tiveram resposta positiva na germinacao com o uso dos metodos com solucao salina.

Qualidade fisiológica de sementes de soja durante o armazenamento após revestimento com agroquímicos

A protecao das sementes contra pragas e doencas nas fases iniciais do desenvolvimento da cultura e de grande importância para a cadeia produtiva da soja. A aplicacao de inseticidas e fungicidas via revestimento de sementes proporciona esta protecao, no entanto, nao deve ocasionar prejuizos a qualidade fisiologica dos lotes de sementes, seja imediatamente depois do revestimento ou apos armazenamento. Para avaliar o efeito do revestimento de sementes de soja com varios agroquimicos sobre a qualidade fisiologica das mesmas durante o armazenamento, foram realizados dois ensaios com as cultivares M6972 IPRO e M7739 IPRO. Vinte quilogramas de cada cultivar foram submetidos a revestimento com os produtos Cropstar, Derosal Plus, Standak Top e Avicta Completo, avaliando-se a primeira contagem de germinacao, germinacao, envelhecimento acelerado e emergencia em canteiro das sementes, durante 60 dias de armazenamento sob condicoes ambientais nao controladas. O armazenamento sob condicoes de temperatura e umidade relativa nao controladas influencia negativamente a qualidade fisiologica das sementes de soja. As cultivares usadas responderam de forma diferente ao revestimento de sementes com os diferentes agroquimicos testados. O revestimento de sementes de soja da cultivar M6972 IPRO com Standak Top ou com Avicta Completo mantem a percentagem de emergencia de plântulas durante os 60 dias de armazenamento. O revestimento de sementes de soja da cultivar M7739 IPRO com Standak Top ocasiona maior qualidade fisiologica de sementes do que os demais revestimentos.

Performance fisiológica de sementes de milheto (Pennisetum americanum) tratadas com bioativador

No Brasil, de entre as especies de gramineas forrageiras tropicais utilizadas para pastagens, que se reproduzem por sementes, destaca-se o milheto como promissor pela sua ampla adaptacao a diferentes tipos de clima, inclusive o da regiao sul do pais. Geralmente, os inseticidas e fungicidas sao avaliados quanto a eficiencia no controle de pragas e doencas, todavia, alguns podem provocar efeitos ainda pouco conhecidos, nomeadamente a capacidade de modificar o metabolismo e a morfologia vegetal (bioativador). O objetivo deste trabalho foi avaliar a influencia do inseticida tiametoxam no comportamento fisiologico de sementes de milheto. Foram utilizados tres lotes de sementes de milheto, e as concentracoes do produto 100; 200; 300 e 400 ml de tiametoxam para 100 kg de sementes; tambem se analisou a nao aplicacao do inseticida. Para a avaliacao da qualidade fisiologica das sementes foram conduzidos os testes de primeira contagem de germinacao e germinacao final, teste de frio, teste de envelhecimento acelerado e testes de comprimento de plântula (parte aerea e radical). Verificou-se que o produto tiametoxam estimula o desempenho fisiologico de sementes de milheto, com intensidade variavel de acordo com o lote. Doses de 210 a 230 ml de produto por 100 kg de semente mostram maior eficiencia ao favorecer o desempenho fisiologico de sementes de milheto.

Protrusão da radícula e métodos para superação de dormência de sementes de trigo

The objective was to study the effectiveness of treatments to overcome dormancy of Triticum aestivum L. seeds used four seed lots (1, 2, 3 and 4), BRS Guamirim with an initial moisture content of 12.5%. The treatments were: pre-cooling temperature of 5 to 10 °C; pre-drying temperature of 30 to 35 °C; pre-drying at 50 °C for a period of undergoing exposure 72 and 96 h; imbibition of the germination test substrate using solution of gibberellic acid and potassium nitrate and untreated seeds (control). Time of radicle protrusion was assessed by soaking curve. The experimental design was completely randomized in a 4 x 6 factorial (seed lots x treatments to overcome dormancy), with five repetitions. In conclusion, lots 2 and 4 had similar performance in the imbibition curve, having a water content of 43.2 and 40.7%, respectively, after a 16 h period due to the higher degree of dormancy of lots with 30 and 38% germination; method using the thermal temperature of 30 to 35 and 50 °C (72 h) has increased efficiency in overcoming wheat seed dormancy being performed in less time when compared with test currently recommended precooling.

Calidad fisiológica de semillas de berenjena, morrón y tomate tratadas con bioactivador

El objetivo de este trabajo es definir la frontera de produccion de arroz y definir los niveles de ineficiencia tecnica y economica a nivel de chacra para un grupo de productores arroceros del Este de Uruguay. La frontera se determino utilizando la metodologia analisis envolvente de datos (DEA). Se determinaron cuatro tipos de eficiencias: tecnica, de escala, de asignacion y economica. En un segundo paso se estimo el efecto de las variables de manejo y ambientales sobre los resultados de eficiencia. La estimacion se realizo mediante una regresion truncada debido a la naturaleza del proceso generador de datos. Los datos corresponden a 573 chacras de arroz, de 26 productores diferentes y corresponden a las zafras entre 2004/05 y 2008/09. Los resultados indican que son 10 las chacras que definen la frontera de produccion considerando rendimientos constantes a escala (eficientes) y que el promedio de eficiencia tecnica es de 0,6. Con rendimientos variables a escala el numero de chacras eficientes aumenta a 25 y el promedio de eficiencia tecnica aumenta a 0,74. Al considerar los precios de insumos y productos el numero de chacras economicamente eficientes es 3 y el promedio de eficiencia es 0,53. Los resultados de la regresion truncada sobre los distintos indicadores de eficiencia indican que los determinantes mas importantes son la eleccion de variedades y el tipo de suelo. Tipo de siembra, laboreos y epoca de laboreo tienen efectos significativos sobre algunos tipos de eficiencia.