ÁCIDO GIBERÉLICO AUXILIA NA SUPERAÇÃO DA DORMÊNCIA FISIOLÓGICA E EXPRESSÃO DE VIGOR DAS SEMENTES DE GRAVIOLA

As sementes de graviola (Annona muricata) apresentam tegumento resistente e impermeável, além de substâncias inibidoras que dificultam a germinação das sementes. Assim, objetivou-se avaliar a contribuição da embebição em ácido giberélico para a superação da dormência e aumento da germinação das sementes de graviola. O delineamento experimental foi inteiramente casualizado, com cinco tratamentos e quatro repetições. As sementes foram escarificadas e em seguida embebidas por 24 horas a 25 ºC em soluções contendo 0; 50; 100; 150 e 200 mg L-1 (ppm) de ácido giberélico. Após este período de embebição as sementes foram submetidas ao teste de germinação, sendo avaliados a porcentagem de germinação, o índice de velocidade e o tempo médio de germinação. As concentrações de ácido giberélico apresentaram efeito sobre a germinação e índice de velocidade de germinação. Conclui-se que a embebição das sementes de graviola na concentração aproximada de 140 ppm de ácido giberélico auxilia na superação da dormência, aumentando a germinação e o índice de velocidade de germinação

High-throughput phenotyping during soybean plant development and seed production under water deficit

O objetivo desse estudo foi observar o efeito do estresse hídrico no desenvolvimento de plantas, nos componentes de produção e na qualidade fisiológica de sementes, além de verificar a eficácia do uso de imagens hiperespectrais em conjunto com técnicas quimiométricas para avaliar a dissimilaridade fenotípica entre cultivares de soja submetida ao déficit hídrico. Para tal, foram utilizados dois cultivares, que diferem em suas respostas quanto ao estresse hídrico, sendo BRASMAX COMPACTA IPRO (suscetível) e DM 66I68 IPRO (tolerante). O ensaio foi realizado em vasos e cultivados em casa de vegetação, onde foram aplicadas as seguintes condições de restrição hídrica: controle (65 % da capacidade de retenção de água do substrato - CRAS); déficit moderado (50 % da CRAS) em V2; déficit severo (30 % da CRAS) em V2; déficit moderado em R6; déficit severo em estádio R6; déficit moderado em V2 e R6; déficit severo em V2 e R6. No primeiro experimento, as plantas de soja oriundas das diferentes condições de restrição hídrica foram amostradas em diversos estádios fenológicos e, partir destas, foram realizadas as seguintes análises: massa de matéria seca; teor de açúcar solúvel; teor de proteínas; teor de lipídeos; avaliação dos componentes de produção; análise do teor de água e da qualidade fisiológica das sementes. No segundo experimento: as plantas (folhas e sementes) coletadas em diferentes estádios de desenvolvimento foram destinadas para aquisição de imagens hiperespectrais, por meio do sensor Sisuchema. Posteriormente, as imagens foram submetidas à análise exploratória de dados e utilizadas em modelos quimiométricos, incluindo Suporte de Vetor de Máquinas e K-vizinho mais distante. Em suma, os resultados demonstraram que o estresse hídrico durante a fase vegetativa afeta negativamente o crescimento e desenvolvimento das plantas do cultivar suscetível, bem como o rendimento. Em contrapartida, o cultivar tolerante manteve seu rendimento apesar das condições adversas. Entretanto, quando o déficit hídrico ocorreu tanto nos estádios vegetativo quanto reprodutivo, o desenvolvimento das plantas, os componentes de produção e a qualidade das sementes foram afetados, independente da suscetibilidade dos cultivares. Além disso, a qualidade das sementes foi mais prejudicada quando o déficit hídrico ocorreu no estádio reprodutivo, influenciando também a composição química das sementes. Por outro lado, as imagens hiperespectrais se mostraram promissoras para realização da fenotipagem de plantas; os modelos de predição baseados em dados foliares apresentaram resultados de classificação excelentes, proporcionando a avaliação da dissimilaridade fenotípica por meio de sensores hiperespectrais, sendo que os modelos delineados a partir dos dados oriundos das sementes não foram consistentes na classificação dos cultivares.The aim of this study was to observe the effect of water stress on plant development, production components and seed physiological quality, as well as to verify the effectiveness of using hyperspectral images in conjunction with chemometric techniques to assess phenotypic dissimilarity between soybean cultivars subjected to water deficit. To this end, two cultivars were used, which differ in their responses to water stress: BRASMAX COMPACTA IPRO (susceptible) and DM 66I68 IPRO (tolerant). The trial was carried out in pots and grown in a greenhouse, where the following water restriction conditions were applied: control (65 % of the substrate\'s water retention capacity - CRAS); moderate deficit (50 % of CRAS) in V2; severe deficit (30 % of CRAS) in V2; moderate deficit in R6; severe deficit in stage R6; moderate deficit in V2 and R6; severe deficit in V2 and R6. In the first experiment, the soybean plants from the different water restriction conditions were sampled at different phenological stages and the following analyses were carried out: dry matter mass; soluble sugar content; protein content; lipid content; evaluation of production components; analysis of water content and seed physiological quality. In the second experiment, plants (leaves and seeds) collected at different stages of development were used to acquire hyperspectral images using the Sisuchema sensor. The images were then subjected to exploratory data analysis and used in chemometric models, including Support Vector Machines and K-farthest neighbor. In summary, the results showed that water stress during the vegetative phase negatively affects the growth and development of the plants of the susceptible cultivar, as well as the yield. In contrast, the tolerant cultivar maintained its yield despite the adverse conditions. However, when water deficit occurred in both the vegetative and reproductive stages, plant development, production components and seed quality were affected, regardless of the susceptibility of the cultivars. In addition, seed quality was more impaired when water deficit occurred in the reproductive stage, also influencing the chemical composition of the seeds. On the other hand, hyperspectral images proved promising for plant phenotyping; the prediction models based on leaf data showed excellent classification results, allowing phenotypic dissimilarity to be assessed using hyperspectral sensors, while the models drawn up using data from seeds were not consistent in classifying cultivars

Evaluation of the internal morphology and vigor of cowpea seeds by image analysis techniques

Os objetivos deste trabalho consistiram na avaliação da morfologia interna de sementes de feijão-caupi, por meio da análise de imagens radiográficas, relacionando-a com o seu potencial fisiológico e na avaliação do vigor das sementes com a utilização do software Vigor-S&#174; (Sistema de Análise Automatizada do Vigor de Sementes). Neste estudo foram utilizados sete lotes de sementes do cultivar BRS Guariba. A primeira etapa constituiu na avaliação da morfologia interna de sementes, onde as sementes foram submetidas ao teste de raios X e posteriormente ao teste de germinação. Na determinação dos os percentuais de espaço vazio entre a área embrionária e o tegumento das sementes, foi utilizado o software ImageJ; com base nos resultados obtidos, foi realizada a classificação das sementes em diferentes categorias. A segunda etapa do experimento consistiu na avaliação do vigor das sementes por meio dos testes de primeira contagem de germinação, envelhecimento acelerado, condutividade elétrica, emergência e velocidade de emergência de plântulas em areia e o uso do sistema computadorizado de imagens de plântulas Vigor-S (Sistema de Análise Automatizada do Vigor de Sementes), em duas épocas de avaliação. Os dados foram submetidos a análise da variância, em delineamento inteiramente casualizado e suas médias foram comparadas pelo teste de Tukey (p <= 0,05). Concluiu-se que a análise de raios X permite a identificação de diferentes tipos de danos e que a presença de danos nas sementes pode afetar a germinação, dependendo da extensão destes e de sua localização, possibilitando estabelecer relações de causa-efeito; o emprego do software ImageJ foi eficiente na mensuração de espaços vazios na cavidade interna de sementes de feijão-caupi; lotes com sementes que contém maior espaço resultam em maior número de plântulas anormais e sementes mortas. A análise computadorizada de plântulas por meio do software Vigor-S, com plântulas aos três dias de idade é uma alternativa segura para detectar diferenças de vigor entre os lotes.The objectives of this research were to evaluate the internal morphology of cowpea seeds, through the analysis of radiographic images, relating to the physiological potential and the evaluation of seed vigor with the use of Vigor-S&#174; software (Automated Seed Vigor Analysis system). In this study, seven lots of cowpea seeds, cultivar BRS Guariba, were used. The first step was the evaluation of seed internal morphology, submitting the seeds to the X- ray test and later to the germination test. To determine the percentages of free space between the embryonic area and the seed coat, the ImageJ software was used; based on the results obtained, the seeds were classified into different classes. The second step was to evaluate seed vigor by germination first count, accelerated aging test, electrical conductivity, seedling emergence and speed of emergence in sand and the use of the Vigor-S computerized seedling imaging system, in two evaluation periods. Data were subjected to analysis of variance in a completely randomized design and their means were compared by Tukey test (p <= 0.05). It was concluded that X-ray analysis allows the identification of different types of damage and the presence of seed damage affect germination depending on their extension and location, allowing the establishment of cause-effect relationships. ImageJ software is an effective tool for measuring free spaces in the internal cavity of cowpea seeds; seed lots with higher percentage of free space resulting from abnormal seedlings and dead seeds Computerized seedling analysis using Vigor-S software with three-day-old seedlings is a useful alternative to detect vigor differences between lots

Morphology and germination of Vigna unguiculata (L.) Walp. seeds

Abstract: The occurrence of damage and empty space inside the seed can directly affect germination. The aim of this study was to evaluate the relationship between the occurrence of damage or empty space inside cowpea seeds and the physiological potential. In this study, seven lots of seeds of the cultivar ‘BRS Guariba’ were subjected to the X-ray test to identify damage by tissue deterioration, mechanical damage, damage by insects and malformed seeds and, later, to the germination test. The percentage of empty space between the embryonic area and the seed coat was determined from radiographic images in ImageJ software. Based on the results obtained, the seeds were classified into different categories, and the results were compared with the germination data. It was concluded that the analysis of radiographic images allowed the identification of damage and measurement of empty space in the internal cavity of the seeds, making it possible to establish a relationship between internal morphology and germination. The presence of damage, especially that caused by tissue deterioration or mechanical damage, depending on its location and intensity, has the potential to negatively affect the germination of cowpea seeds. Likewise, seeds that contain higher levels of empty space in their internal cavity tend not to germinate or to generate abnormal seedlings at the time of germination

pH of exudate test in the physiological quality of crambe seeds

ABSTRACT: Crambe is a rapeseed with high oil content and can be used as a winter cover or as a source of raw material for the production of biodiesel, however espite the growing interest in the culture, research on the subject is still incipient, especially concerning the seed production and analysis technology. The purpose of this study is to evaluate the physiological quality of crambe seeds, 'FMS Brilhante' cultivar, by testing the pH of exudate. Five seed lots were submitted to the determination of water content and the tests of germination and vigor (first count, emergence and tetrazolium). In the conduction of pH exudate test, temperatures (25 and 30oC), and periods of seed imbibition in water (15, 30 and 45 minutes) were tested. The experiment was conducted in a completely randomized manner, with four replicates, and the mean values were compared by the Tukey test at 5% probability; Pearson correlation between the pH of the exudate and initial tests was also made. Testing the pH of exudate is promising for separating lots of crambe seeds and the following combinations of 25°C/30 minutes or 30°C/45 minutes can be used

ÁCIDO GIBERÉLICO AUXILIA NA SUPERAÇÃO DA DORMÊNCIA FISIOLÓGICA E EXPRESSÃO DE VIGOR DAS SEMENTES DE GRAVIOLA

As sementes de graviola (Annona muricata) apresentam tegumento resistente e impermeável, além de substâncias inibidoras que dificultam a germinação das sementes. Assim, objetivou-se avaliar a contribuição da embebição em ácido giberélico para a superação da dormência e aumento da germinação das sementes de graviola. O delineamento experimental foi inteiramente casualizado, com cinco tratamentos e quatro repetições. As sementes foram escarificadas e em seguida embebidas por 24 horas a 25 ºC em soluções contendo 0; 50; 100; 150 e 200 mg L-1 (ppm) de ácido giberélico. Após este período de embebição as sementes foram submetidas ao teste de germinação, sendo avaliados a porcentagem de germinação, o índice de velocidade e o tempo médio de germinação. As concentrações de ácido giberélico apresentaram efeito sobre a germinação e índice de velocidade de germinação. Conclui-se que a embebição das sementes de graviola na concentração aproximada de 140 ppm de ácido giberélico auxilia na superação da dormência, aumentando a germinação e o índice de velocidade de germinação

PHYSIOLOGICAL QUALITY OF Brachiaria brizantha SEEDS TREATED WITH FUNGICIDE AND INSECTICIDE

This study aimed to evaluate the effects of chemical treatment of seeds with fungicide and insecticide on the seed physiological quality of Brachiaria brizantha cultivar MG5. Two experiments with four replicates were carried out in a completely randomized design. In the first experiment, the seeds were treated with the fungicide pyraclostrobin + fipronil + thiophanate-methyl and in the second, with the insecticide thiamethoxam, both at doses of 0, 150, 300, 450, and 600 mL of commercial product (CP)/100 kg of seeds. Physiological characterization was done on the basis of the first germination count, germination (%), emergence (%), emergence speed index, and length and dry mass of shoot and root. The treatment of B. brizantha seeds with the fungicide pyraclostrobin + fipronil + thiophanate-methyl benefits the physiological quality of seeds, improving germination and root development, with no phytotoxic effect up to the dose of 600 mL of CP/100 kg of seeds. The insecticide thiamethoxam has a biostimulating effect on B. brizantha cultivar MG5 up to the dose of 270 mL of CP/100 kg of seeds, but is phytotoxic in larger doses

HUMIC ACID ON GERMINATION AND VIGOR OF CORN SEEDS

The development of technologies to increase stand establishment efficiency and seed vigor, as well as to maximize profits, is of fundamental importance for the sustainability of agriculture. Products based on humic substances, such as humic acids, have been recently used in Brazilian agriculture to produce seedlings with high vigor, which positively influences the establishment of the initial stand. Thus, this study aimed to evaluate the effect of treatment of corn seeds with a commercial humic acid-based product, Humykos® (18% of humic acid content), on germination and seedling vigor. The treatments consisted of six doses (0, 100, 200, 300, 400, and 500 mL 100 kg-1 seed) of Humykos®, and the treated seeds were analyzed for germination and vigor (first count, emergence, emergence speed index, length, and dry mass of shoots and roots). Our results show that humic acid promotes greater seedling growth and increased shoot dry mass in corn; in addition, it has a positive influence on the emergence speed index up to a dose 158 mL 100 kg-1 seeds

EXUDATE pH AND FLOODING TESTS TO EVALUATE THE PHYSIOLOGICAL QUALITY OF SOYBEAN SEEDS

The present study aimed to assess the variations in the parameters of the exudate pH and flooding tests to evaluate the physiological quality of soybean seeds. We subjected the lots of soybean seeds to germination, emergence, exudate pH, and flooding tests. Further, water content of the seeds, first count of germination, and emergence speed index were also determined. The exudate pH test studied the variations in the soaking period and temperature, while the flooding test assessed the variations in the amount of water and temperature at different periods of immersion. The experiment design was completely randomized. The results were presented as means and were compared using the Scott-Knott test at 5% probability. The Pearson’s correlation coefficient between the exudate pH and emergence of seedlings, and also between the flooding test result and emergence of seedlings were calculated. The results of the study indicated that the exudate pH test can be used to evaluate the physiological quality of soybean seeds after 30 min of imbibition at 20 °C. Further, the flooding test was efficient in evaluating the vigor of soybean seeds after 4 h of immersion either in 50 mL of distilled water at 25 °C or in 75 mL of distilled water at 30 °C