Pré-tratamentos com luz em sementes de tomateiro para indução de tolerância ao déficit hídrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Extratos de Ascophyllum nodosum no tratamento de sementes de milho e soja: avaliações fisiológicas e moleculares

A obtenção de uma lavoura com população adequada de plantas depende da utilização de diferentes práticas agronômicas, estando o sucesso condicionado ao uso de sementes de boa qualidade. No entanto, a semeadura dificilmente é realizada em condições ideais o que resulta em problemas na emergência das plantas. Grande é a procura por alternativas que melhorem a germinação e o desenvolvimento inicial dos cultivos resultando em uniformidade de emergência, garantindo o estande e culminando em produção. O tratamento de sementes com agroquímicos fitossanitários é uma solução parcial no combate de agentes fitopatológicos e pragas, mas poucas são as soluções adotadas para melhorar o desenvolvimento vegetal inicial, que pode levar a desuniformidade e falhas no estande gerando prejuízos econômicos. Os extratos de algas já demonstraram em diversos estudos sua eficiência no desenvolvimento vegetal quando aplicados em plantas. Porém poucos são os estudos voltados para os efeitos dos extratos de algas na germinação e emergência. Assim, o intuito deste trabalho foi testar o extrato comercial de Ascophyllum nodosum, e diferentes fracionamentos do mesmo, no tratamento de sementes de soja e milho. Avaliou-se o efeito de diferentes doses no desenvolvimento das plântulas e as doses de melhor resposta foram utilizadas no tratamento de sementes de soja a fim de associar as respostas obtidas à expressão gênica de 9 genes relacionados ao processo germinativo em 24 e 48h de embebição. Sementes de soja tratadas com o extrato comercial resultaram em plântulas menos desenvolvidas o que pode estar relacionado ao alto teor de sais contidos no produto. O tratamento com as demais frações favoreceu o desenvolvimento das plântulas, principalmente o desenvolvimento radicular. Sementes de milho tratadas não apresentaram desenvolvimento tão satisfatório quanto as sementes de soja tratadas. A análise da expressão gênica relativa demonstrou que o tratamento com frações do extrato comercial é capaz de regular algumas vias do metabolismo hormonal, como a isopentenil transferase e a GA20 oxidase 2, e do catabolismo de reservas, como a acil-CoA oxidase. Em condições ótimas, o tratamento de sementes de soja com frações do extrato comercial de A. nodosum favoreceu o desenvolvimento inicial das plântulas de soja, no entanto não ocasionou grandes alterações no desenvolvimento de milho. Este estudo demonstrou a possibilidade de utilização de frações do extrato de A. nodosum no favorecimento do desenvolvimento inicial de plântulas de soja. Maiores estudos são necessários quanto às respostas em campo e na atenuação de estresses para viabilizar seu uso como um bioestimulante em sementes.

Qualidade fisiológica de sementes de Moringa oleifera lam. por meio da análise de imagens

Several tests that evaluate the quality of seeds are destructive and require time, which is considered long and expensive in the processes that involves the production and marketing of seed. Thus, techniques that allow reducing the time related to assess the quality of seed lots is very favorable, considering the technical, economic and scientific point of view. The techniques images of seed analyzed both by X-ray such as digital images, represent alternative for this sector, and are considered reproducible and fast, giving greater flexibility and autonomy to the activities of production systems. Summarily, the objective was to analyze the internal morphology of seeds of this species through x-rayed images and the efficiency of weed seed area increased during soaking through image analysis and compare them with the results of germination tests and force the evaluation of physiological seed quality. For X-ray tests, the seeds were exposed for 0.14 seconds at radiation 40kV and 2.0 mAs. Were analyzed images using the ImageJ program and subsequently put to germinate in B.O.D chamber at 27 ° C, in which there was the comparison of results for germination. To determine the test area increase (% IA), seeds were used with and without seed coat, maintained the B.O.D chamber at 15 ° to 20 ° C, the seeds were photographed before and after the soaking period, the results were compared to the germination rates. For the X-ray test, it was observed that seeds with empty area greater than 20%, showed a higher percentage of abnormal seedlings. And the area increment analysis showed that it is possible to rank the batch after 8 hours of imbibition at 15 ° C according to the germination and vigor tests

Testes para a avaliação da qualidade fisiológica de sementes de Moringa oleifera Lam

The evaluation of seed vigor is an important factor for detection of lots of high quality seeds, so that development of procedures to evaluate the physiological potential has been an important tool in quality control programs seeds. In this sense the study aimed to adapt the methodologies of accelerated aging, electrical conductivity and potassium leaching to evaluate Moringa oleifera seed vigor LAM.. Therefore, four lots of moringa seeds were subjected to the germination tests, seedling emergence, speed of emergence index, emergence first count, length and dry mass of seedlings and cold test for their physiological characterization, in addition to accelerated aging, electrical conductivity and potassium leaching. The experimental design was completely randomized with four replications of 50 seeds and the means compared by Tukey test at 5% probability. For accelerated aging the periods were studied aging 12, 24 and 72 hours at 40, 42 and 45°C. For the electrical conductivity test was used to a temperature of 25°C for periods of 4, 8, 12, 16 and 24 hours of immersion in 75 to 125 mL of distilled water, using 25 to 50 seeds, and for potassium leaching test samples were used 25 to 50 seeds, placed in plastic cups containing 70 and 100 mL of distilled water at 25°C for periods of 1, 2, 3, 4, 5 and 6 hours. From the results obtained, it can be inferred that the methods best fit for the accelerated aging test Moringa seeds were a temperature of 40°C for 12 to 72 hours, 42°C 72 hours 45°C 24 hours . In the electrical conductivity test Moringa seeds, the combination of 50 seeds in 75 mL distilled water for a period of immersion of 4 hours and 50 seeds in 125 mL of 4 hours were efficient for the differentiation of lots of Moringa seeds as to vigor and for potassium leaching test moringa seeds, the combination of 50 seeds in 100mL of distilled water allowed the separation of lots of four levels of vigor, at 2 hours of immersion, showing promise in evaluate the quality of moringa seeds.

Testes para a avaliação da qualidade fisiológica de sementes de Moringa oleifera Lam

The evaluation of seed vigor is an important factor for detection of lots of high quality seeds, so that development of procedures to evaluate the physiological potential has been an important tool in quality control programs seeds. In this sense the study aimed to adapt the methodologies of accelerated aging, electrical conductivity and potassium leaching to evaluate Moringa oleifera seed vigor LAM.. Therefore, four lots of moringa seeds were subjected to the germination tests, seedling emergence, speed of emergence index, emergence first count, length and dry mass of seedlings and cold test for their physiological characterization, in addition to accelerated aging, electrical conductivity and potassium leaching. The experimental design was completely randomized with four replications of 50 seeds and the means compared by Tukey test at 5% probability. For accelerated aging the periods were studied aging 12, 24 and 72 hours at 40, 42 and 45°C. For the electrical conductivity test was used to a temperature of 25°C for periods of 4, 8, 12, 16 and 24 hours of immersion in 75 to 125 mL of distilled water, using 25 to 50 seeds, and for potassium leaching test samples were used 25 to 50 seeds, placed in plastic cups containing 70 and 100 mL of distilled water at 25°C for periods of 1, 2, 3, 4, 5 and 6 hours. From the results obtained, it can be inferred that the methods best fit for the accelerated aging test Moringa seeds were a temperature of 40°C for 12 to 72 hours, 42°C 72 hours 45°C 24 hours . In the electrical conductivity test Moringa seeds, the combination of 50 seeds in 75 mL distilled water for a period of immersion of 4 hours and 50 seeds in 125 mL of 4 hours were efficient for the differentiation of lots of Moringa seeds as to vigor and for potassium leaching test moringa seeds, the combination of 50 seeds in 100mL of distilled water allowed the separation of lots of four levels of vigor, at 2 hours of immersion, showing promise in evaluate the quality of moringa seeds.

Uso de indicadores bioquímicos na qualidade fisiológica de sementes florestais

The scientific research in seed technology is based on techniques that aim the reduction of costs and time, standardization, improvement and establishment of analytical methods while maintaining a high level of reliability of the results. This study sought to elucidate the reliability of electrical conductivity and pH of the exudate compared to the classic germination test, which was developed in two separate studies, however interrelated with each other, as to their final goals. The experimental material of this study consisted of seeds of the species Aspidosperma parvifolium (guatambu), Aspidosperma polyneuron (peroba-rosa), Cabralea canjerana (canjerana), Cariniana legalis (jequitibá), Gallesia integrifolia (pau-d'alho), Handroanthus chrysotrichus (ipê-amarelo), Lonchocarpus campestris (rabo-de-bugio) and Pterogyne nitens (amendoim-do-campo). The physiological quality of the studied seed species was evaluated through the electrical conductivity and pH test of the exudate by mass and individual methods being compared and correlated with the results obtained in the germination test. In addition to the tested methods, imbibition periods of the seeds were evaluated for conductivity and pH, which corresponded to 2, 4, 6, 8, 24 and 48 hours. The electrical conductivity test was efficient in both of the used methods to evaluate the physiological quality of the studied seed species when compared to the standard germination test. The pH test of the exudate applied by the individual method was more efficient and thorough to evaluate the physiological quality of the studied seed species, than the mass method. For the species Gallesia integrifolia, Cariniana legalis and Lonchocarpus campestris the pH tests of the exudate tests were not efficient due to poor or absent correlation between germination and pH.

Desempenho de sementes de soja revestidas com biopolímeros

The use of biopolymers that help to fix pesticides efficiently and degrade easily without harming the environment, and still improve the physiological performance of field soybean seed may bring contributions to the soybean yield. This study aimed to evaluate the effect of cassava starch polymers (AM), sodium alginate (ALG) and polyvinyl alcohol (PVOH), in the concentrations 2, 4 and 6 g / 100 ml of solution, in the physiological attributes of seeds soy, seed speed soaking and performance of soybean seeds after three months of storage. The soybean variety used was the NK 7059 RR. The experimental design used for the three studies was a factorial with 48 experimental units: 3 polymers (AM, ALG and PVOH), 4 different concentrations (0%, 2%, 4% and 6%), with four replications, in a completely randomized design. It was observed the level of significance of the factors and their interactions, applying the test F. The polymers were evaluated by the Tukey test at 5% probability, and the concentrations were evaluated by polynomial regression. The witness obtained better results for most variables studied. Among the polymers, the best coating was observed PVOH because it was the less viscous polymer and visually not served as a substrate for microorganisms. However, also, satisfactory results were obtained for the AM and ALG polymers at a concentration of 2%. There was not interference of the polymers studied with regard to reduction of imbibition rate of soybean seeds. The hydrophilicity of polymers, mainly the AM and ALG accelerated soaking seeds harming germination at concentrations 4% and 6%. In general, the higher the concentration of polymers tended to worse results.

Regulação coordenada da mobilização de lipídios e proteínas por hormônios, fontes de carbono e nitrogênio durante o crescimento pós-germinativo em Girassol

The mobilization of food reserves in storage tissues and allocation of their hydrolysis products in the growing axis are critical processes for the establishment of seedlings after germination. Therefore, it is crucial for mobilization of reserves to be synchronized with the growing axis, so that photosynthetic activity can be started before depletion of reserves. For this, integrative approaches involving different reserves, different hydrolysis products and interaction between storage and growing axis tissues, either through hormones or metabolites with signaling role, can contribute greatly to the elucidation of the regulation mechanisms for reserve mobilization. In this study, was hypothesized that hormones and metabolites have different actions on reserve mobilization, and there must be a crossed effect of sugars on the mobilization of proteins and amino acids on lipids and starch mobilization in sunflower seedlings. This study was conducted with seeds of sunflower (Helianthus annuus L.) hybrid Helio 253 using in vitro culture system. Seeds were germinated on Germitest® paper and grown on agar-water 4 g/L without addition of nutrients during 9 days after imbibition (DAI) for growth curve. To verify the effect of metabolites and hormones, seedlings were transferred in the 2nd DAI to agar-water 4 g/L supplemented with increasing concentrations of sucrose or L-glutamine, abscisic acid, gibberellic acid or indolebutyric acid. The results of this study confirm that the mobilization of lipids and storage proteins occurs in a coordinated manner during post-germination growth in sunflower, corroborating the hypothesis that the application of external carbon (sucrose) and nitrogen (L-glutamine) sources can delay the mobilization of these reserves in a crossed way. Moreover, considering the changes in the patterns of reserve mobilization and partition of their products in seedlings treated with different growth regulators, it is evident that the effects of metabolites and hormones must involve, at least in part, distinct mechanisms of action

Dimensionamento amostral para determinação da condutividade elétrica individual de sementes de girassol.

RESUMO: O teste de condutividade elétrica é um teste de vigor de sementes utilizado para avaliar a qualidade das sementes e complementar o teste de germinação. O tamanho da amostra necessária para a estimação da média de condutividade elétrica de sementes é diretamente proporcional à variabilidade dos dados e confiabilidade desejada na estimativa. Uma técnica adequada para dimensionamento amostral é a utilização de intervalos de confiança, obtidos por reamostragem. Essa técnica tem a vantagem de não depender da distribuição de probabilidade dos dados. Assim, o objetivo deste trabalho foi estimar o tamanho de amostra necessário para o teste de condutividade elétrica individual em sementes de girassol. Foram utilizadas sete lotes de sementes de girassol, sendo três lotes da cultivar Hélio 250 (A, B e C), dois lotes da cultivar BRS 323 (D e E) e dois lotes da cultivar BRS 324 (F e G). O teste de condutividade elétrica individual foi realizado com 400 sementes de cada lote e o tamanho de amostra foi determinado pelo número de sementes a partir do qual a amplitude do intervalo de confiança de 95% (AIC95%) foi menor ou igual a 10, 15 e 20% da estimativa da média. Tempos de embebição de vinte e quatro hora possibilitam utilizar os menores tamanhos de amostras. O tamanho de amostra de 257 sementes é recomendado para a amplitude do intervalo de confiança de 95% igual a 20% da estimativa da média. ABSTRACT: The aim of this study was to estimate the sample size required for the individual electrical conductivity test in sunflower seeds. The sample size of 257 seeds is recommended for the amplitude of the 95% confidence interval of 20% of the mean estimate.

Germinação de sementes de feijão submetidas à submersão em água.

2015

Germinação de sementes e otimização de técnicas de micropropagação de umbuzeiro (spondias tuberosa, arr.) anacardiaceae

The brazilian-plum (Spondias tuberosa, His) is a tropical fruit tree that has been consolidated in the market for agribusiness processing, due to its characteristic flavor of fruit. Accordingly, studies to optimize the propagation of plants are necessary for production of seedlings with agronomic and quality assurance measures. This study aimed at determining the efficient techniques for uniform seed germination, as brazilian-plum seed present mechanical dormancy, and establish optimal culture media for multiplication of shoots from the in vitro micropropagation. Firstly, in a greenhouse at the Universidade Federal do Rio Grande do Norte, was evaluated the influence of different methods of breaking dormancy in the emergence of seedlings of brazilian-plum and speed of germination (IVG) of seeds. After 60 days of cultivation, it was found that splay in the distal portion of the seed was the best treatment, with rates of 85.33% in germinability and 3.415 of IVG, compared with the treatment of seed-soaking in water for 12h + humus and the control group. Subsequently, new sources of seedling explants were obtained in studies of tissue culture. Laboratory of Plant Biotechnology that the university, was used stem apex, nodal segments and internodes in search of decontamination with various concentrations of calcium hypochlorite [Ca(OCl)2] and micropropagation, inoculating them in half WPM (1980) with various concentrations of 6-benzylaminopurine (BAP). We used 10 sample units with three replications for different concentrations of [Ca(OCl)2], BAP and explants type. After thirty days, which was observed for the control of contamination, during the establishment in vitro, concentrations of [Ca(OCl)2] between 0.5% and 2.0% were effective in combating exogenous contamination of the apex. In nodal segments and internodes, concentrations of [Ca(OCl)2] between 1.0% and 2.0% and 1.5% and 2.0% were respectively, sufficient to reduce the percentage of losses in these infestations explants. For micropropagation, the culture medium supplemented with 0.1 mg.L-1 BAP promotes better development of multiple shoots per explants from nodal segment. However, success does not get to shoot training in internodal segment