Morphological and physiological changes during maturation of okra seeds evaluated through image analysis

This study was performed to associate specific morphological parameters, defined by X-ray images, with seed performance of okra (Abelmoschus esculentus (L.) Moench) during maturation. Fruits of cultivar Santa Cruz 47 at different developmental stages were collected at five-day intervals (from 5 to 65 days after anthesis) and water content, dry matter, germination and vigor were determined in seeds extracted immediately after each harvest or after temporary storage for seven days. X-ray tests were also performed after each harvest and the images were analyzed by ImageJ® software to produce data of aspect ratio (relation between major and minor axes of the ellipse surrounding the seed perimeter) and percentage of free space area in the inner seed cavity. Physiological maturity (maximum accumulation of dry matter) was reached at 30 days after anthesis (DAA), when seed water content was 56.6 %. Seed germination and vigor increased during maturation, achieving the maximum at 50 DAA. Seeds showed morphological changes during maturation, becoming more spherical (aspect ratio near 1.0); at the same time, the free space available in the inner cavity of the seed decreased. This parameter can be successfully used as a marker of physiological maturity when values equal or lower than 5 % are reached.

Morphological and physiological changes during maturation of okra seeds evaluated through image analysis

This study was performed to associate specific morphological parameters, defined by X-ray images, with seed performance of okra (Abelmoschus esculentus (L.) Moench) during maturation. Fruits of cultivar Santa Cruz 47 at different developmental stages were collected at five-day intervals (from 5 to 65 days after anthesis) and water content, dry matter, germination and vigor were determined in seeds extracted immediately after each harvest or after temporary storage for seven days. X-ray tests were also performed after each harvest and the images were analyzed by ImageJ® software to produce data of aspect ratio (relation between major and minor axes of the ellipse surrounding the seed perimeter) and percentage of free space area in the inner seed cavity. Physiological maturity (maximum accumulation of dry matter) was reached at 30 days after anthesis (DAA), when seed water content was 56.6 %. Seed germination and vigor increased during maturation, achieving the maximum at 50 DAA. Seeds showed morphological changes during maturation, becoming more spherical (aspect ratio near 1.0); at the same time, the free space available in the inner cavity of the seed decreased. This parameter can be successfully used as a marker of physiological maturity when values equal or lower than 5 % are reached.(AU)

Vigor-S, a new system for evaluating the physiological potential of maize seeds

The refinement of vigor tests and the possibility of utilizing computer resources for the effective evaluation of the seed physiological potential have attracted considerable interest from research and seed technologists. The aim of this study was to evaluate the physiological potential of maize seeds using the newly-created Automated Analysis of Seed Vigor System (Vigor-S) compared with other recommended seed vigor tests; two maize hybrids were used, each represented by seven seed lots. Germination and vigor (cold test, saturated salt accelerated aging, and field seedling emergence) evaluations were conducted. For the evaluation of seed vigor with the use of seedling image analysis resources, two systems were compared: the Seed Vigor Imaging System (SVIS®), developed by Ohio State University, USA and the Vigor-S, resulting from collaboration between USP/ESALQ and EMBRAPA (Embrapa Instrumentation). Using these two systems, three day old seedlings were scanned and the images were analyzed. Similar results for the vigor index, uniformity of development, and seedling length were obtained. The computerized image analysis of seedlings using Vigor-S has advantages with respect to accuracy, speed, and the possibility of automatic application to a worksheet. It is a consistent alternative for the evaluation of maize seed vigor, and produces information compatible with that obtained by the accelerated aging test and SVIS®.

Vigor-S, a new system for evaluating the physiological potential of maize seeds

The refinement of vigor tests and the possibility of utilizing computer resources for the effective evaluation of the seed physiological potential have attracted considerable interest from research and seed technologists. The aim of this study was to evaluate the physiological potential of maize seeds using the newly-created Automated Analysis of Seed Vigor System (Vigor-S) compared with other recommended seed vigor tests; two maize hybrids were used, each represented by seven seed lots. Germination and vigor (cold test, saturated salt accelerated aging, and field seedling emergence) evaluations were conducted. For the evaluation of seed vigor with the use of seedling image analysis resources, two systems were compared: the Seed Vigor Imaging System (SVIS®), developed by Ohio State University, USA and the Vigor-S, resulting from collaboration between USP/ESALQ and EMBRAPA (Embrapa Instrumentation). Using these two systems, three day old seedlings were scanned and the images were analyzed. Similar results for the vigor index, uniformity of development, and seedling length were obtained. The computerized image analysis of seedlings using Vigor-S has advantages with respect to accuracy, speed, and the possibility of automatic application to a worksheet. It is a consistent alternative for the evaluation of maize seed vigor, and produces information compatible with that obtained by the accelerated aging test and SVIS®.(AU)

Swingle citrumelo seed vigor and storability associated with fruit maturity classes based on RGB parameters

ABSTRACT: Citrus seeds normally have low storability. Identifying an optimal fruit harvest time for production of high vigor seeds is important for nurseries; however, identifying this stage for Swingle citrumelo fruits has been based only on visual color examination, and research related to this parameter has been inconsistent. The main objective of this study was to evaluate a red-green-blue (RGB) color measurement system for successful identification of Swingle citrumelo fruits possessing seeds with maximum physiological potential and storability. Fruits were harvested at three ripening stages identified as green (G), greenish-yellow (GY), and yellow (Y) pericarp, photographed, and the images processed using ImageJ software. Data were expressed as the average pixel value of R, G and B color components and a mean RGB pixel value (R+G+B/3). After harvest, seeds were evaluated for water content, germination, seedling emergence, length, dry mass and vigor as measured by the Seed Vigor Imaging System - SVIS (uniformity and vigor indexes) after 0 and 5 months storage (5 °C and 65 % relative humidity). Percentage of ruptured coat seeds was also evaluated after extraction. The R color component provided the best identification of each G, GY and Y fruits. Seeds extracted from GY fruits had higher storage potential compared with seeds from G and Y fruits. Thus, precise fruit ripening classification can be generated using the RGB color system to identify the best time for harvest to obtain seeds with greater physiological and storage potential.

Swingle citrumelo seed vigor and storability associated with fruit maturity classes based on RGB parameters

ABSTRACT: Citrus seeds normally have low storability. Identifying an optimal fruit harvest time for production of high vigor seeds is important for nurseries; however, identifying this stage for Swingle citrumelo fruits has been based only on visual color examination, and research related to this parameter has been inconsistent. The main objective of this study was to evaluate a red-green-blue (RGB) color measurement system for successful identification of Swingle citrumelo fruits possessing seeds with maximum physiological potential and storability. Fruits were harvested at three ripening stages identified as green (G), greenish-yellow (GY), and yellow (Y) pericarp, photographed, and the images processed using ImageJ software. Data were expressed as the average pixel value of R, G and B color components and a mean RGB pixel value (R+G+B/3). After harvest, seeds were evaluated for water content, germination, seedling emergence, length, dry mass and vigor as measured by the Seed Vigor Imaging System - SVIS (uniformity and vigor indexes) after 0 and 5 months storage (5 °C and 65 % relative humidity). Percentage of ruptured coat seeds was also evaluated after extraction. The R color component provided the best identification of each G, GY and Y fruits. Seeds extracted from GY fruits had higher storage potential compared with seeds from G and Y fruits. Thus, precise fruit ripening classification can be generated using the RGB color system to identify the best time for harvest to obtain seeds with greater physiological and storage potential.(AU)

Seed vigor testing: an overview of the past, present and future perspective

The assessment of seed vigor has many important implications to the seed industry as a basic monitoring of seed physiological potential during different phases of seed production and a support for strategic decisions regarding the selection of high quality seedlots to meet the consumer demand. The potential attributes of seed vigor as a fundamental physiological seed characteristic and its association with field stand establishment and crop productivity has been worldwide recognized from the 1960s onward. This led to the diversification of research approaches involving the synchronization of different physiological characteristics and events that determine the potential for high performance during seed storage and after sowing. The basic objective of vigor testing is to provide a consistent identification of differences in physiological potential among seedlots of commercial value and this represents a more sensitive parameter than the germination test. There are various procedures to assess seed vigor including those that directly or indirectly evaluate seed metabolic state or identify seed tolerance to specific stress(es). At the same time, in more recent years, new knowledge has come from molecular biology, biotechnology, biophysics and seed and seedling imaging analyses; these approaches has been important complements to traditional seed research.. This text has the purpose to emphasize the role of Brazilian research in seed vigor, whose competence is internationally recognized, and to provide an overview of the evolution of knowledge also attempting to highlight events that contributed to the advancement of research on the subject.

Seed vigor testing: an overview of the past, present and future perspective

The assessment of seed vigor has many important implications to the seed industry as a basic monitoring of seed physiological potential during different phases of seed production and a support for strategic decisions regarding the selection of high quality seedlots to meet the consumer demand. The potential attributes of seed vigor as a fundamental physiological seed characteristic and its association with field stand establishment and crop productivity has been worldwide recognized from the 1960s onward. This led to the diversification of research approaches involving the synchronization of different physiological characteristics and events that determine the potential for high performance during seed storage and after sowing. The basic objective of vigor testing is to provide a consistent identification of differences in physiological potential among seedlots of commercial value and this represents a more sensitive parameter than the germination test. There are various procedures to assess seed vigor including those that directly or indirectly evaluate seed metabolic state or identify seed tolerance to specific stress(es). At the same time, in more recent years, new knowledge has come from molecular biology, biotechnology, biophysics and seed and seedling imaging analyses; these approaches has been important complements to traditional seed research.. This text has the purpose to emphasize the role of Brazilian research in seed vigor, whose competence is internationally recognized, and to provide an overview of the evolution of knowledge also attempting to highlight events that contributed to the advancement of research on the subject.(AU)

Relationship between germination and bell pepper seed structure assessed by the X-ray test

Alternative use of the X-ray test to evaluate seed quality has become increasingly diverse. This study was performed primarily to establish experimental procedures and verify the effectiveness of the X-ray test to detect damage or abnormalities in bell pepper (Capsicum annuum) seed structure associated with germination. Five seed lots each of hybrids Reinger and Sentinel were used. Two hundred seeds per lot were exposed to durations and intensities of X-radiation and visually classified into four categories according to the proportion between the area occupied by the embryo and endosperm in relation to the total cavity area in the internal seed structure, e.g. 0, 50%, 50-75% and 100%. The last category was subdivided into two others based on the occurrence of morphological abnormalities. Seed samples obtained from different X-ray categories were then submitted to germination test at 25ºC for 14 days and subsequently compared with results of the X-ray analysis. Exposure to a 10 kV radiation for 260 s was the most suitable X-ray dose for visualizing seed structure. Seeds in which the area of the internal cavity occupied by the embryo and endosperm varied from 50-75% produced abnormal seedlings or did not germinate. Full seeds (100% of the internal cavity area occupied) with abnormal structure usually originated defective seedlings. As a consequence, the classification of bell pepper seeds according to the proportion occupied by the seed content (embryo + endosperm) allowed a reliable estimation of the degree of seed physical integrity based on X-ray analysis and its association with germination performance.

Relationship between germination and bell pepper seed structure assessed by the X-ray test

Alternative use of the X-ray test to evaluate seed quality has become increasingly diverse. This study was performed primarily to establish experimental procedures and verify the effectiveness of the X-ray test to detect damage or abnormalities in bell pepper (Capsicum annuum) seed structure associated with germination. Five seed lots each of hybrids Reinger and Sentinel were used. Two hundred seeds per lot were exposed to durations and intensities of X-radiation and visually classified into four categories according to the proportion between the area occupied by the embryo and endosperm in relation to the total cavity area in the internal seed structure, e.g. 0, 50%, 50-75% and 100%. The last category was subdivided into two others based on the occurrence of morphological abnormalities. Seed samples obtained from different X-ray categories were then submitted to germination test at 25ºC for 14 days and subsequently compared with results of the X-ray analysis. Exposure to a 10 kV radiation for 260 s was the most suitable X-ray dose for visualizing seed structure. Seeds in which the area of the internal cavity occupied by the embryo and endosperm varied from 50-75% produced abnormal seedlings or did not germinate. Full seeds (100% of the internal cavity area occupied) with abnormal structure usually originated defective seedlings. As a consequence, the classification of bell pepper seeds according to the proportion occupied by the seed content (embryo + endosperm) allowed a reliable estimation of the degree of seed physical integrity based on X-ray analysis and its association with germination performance.

Priming of pioneer tree Guazuma ulmifolia (Malvaceae) seeds evaluated by an automated computer image analysis

Direct seeding is one of the most promising methods in restoration ecology, but low field seedling emergence from pioneer tree seeds still reduces its large scale applicability. The aim of this research was to evaluate seed priming for the pioneer tree species Guazuma ulmifolia. Priming treatments were selected based on seed hydration curves in water and in PEG 8000 solution. Seeds were primed in water for 16 h and in Polyethylene glycol - PEG 8000 (-0.8 MPa for 56 and 88 h) at 20ºC to reach approximately 30% water content. Half of the seed sample of each treatment was dried back to the initial moisture content (7.2%); both dried and non-dried primed seeds as well as the unprimed seeds (control) were tested for germination (percentage and rate) and vigor (electrical conductivity of seed leachates). Seedling emergence percentage and rate were evaluated under greenhouse conditions, while seedling length and uniformity of seedling development were estimated using the automated image analysis software SVIS®. Primed seeds showed the highest physiological potential, which was mainly demonstrated by image analysis. Fresh or dried primed seeds in water for 16 h and in PEG (-0.8 MPa) for 56 h, and fresh primed seeds in PEG for 88 h, improved G. ulmifolia germination performance. It is suggested that these treatments were promising to enhance efficiency of stand establishment of this species by direct seeding in restoration ecology programs.

A semeadura direta é um dos métodos mais promissores para a restauração ecológica, mas a baixa emergência de plântulas em campo a partir de sementes de árvores pioneiras ainda limita sua aplicabilidade em larga escala. Avaliou-se a resposta de sementes da espécie florestal pioneira Guazuma ulmifolia ao condicionamento fisiológico. Os tratamentos foram selecionados com base em curvas de hidratação em água e em solução osmótica de Polietilenoglicol - PEG 8000. As sementes foram condicionadas em água por 16 h e em PEG 8000 (-0,8 MPa por 56 e 88 h) a 20ºC, atingindo teor de água de, aproximadamente, 30%. Metade das amostras de cada tratamento foi secada até atingir teor de água próximo ao inicial (7,2%); em seguida, avaliou-se o desempenho das sementes condicionadas submetidas ao não à secagem, além de sementes não condicionadas (testemunha), quanto à germinação (porcentagem e velocidade) e o vigor (condutividade elétrica dos exudatos das sementes). A porcentagem e a velocidade de emergência de plântulas foram avaliadas em condições de casa de vegetação, enquanto que o comprimento de plântulas e a uniformidade de desenvolvimento das plântulas foram estimados usando o software de análise computadorizada de imagens de plântulas SVIS®. As sementes condicionadas fisiologicamente apresentaram potencial fisiológico superior, demonstrado principalmente pelos resultados da análise de imagens. Assim, as sementes condicionadas em água durante 16 h ou em PEG durante 88 h, ambas não submetidas à secagem subsequente, e as condicionadas em PEG durante 56 h e submetidas a secagem, beneficiaram o desempenho germinativo de G. ulmifolia. Sugere-se que esses tratamentos são promissores para aumentar a eficiência de estabelecimento de estande dessa espécie via semeadura direta em programas de restauração ecológica.

Priming of pioneer tree Guazuma ulmifolia (Malvaceae) seeds evaluated by an automated computer image analysis

Direct seeding is one of the most promising methods in restoration ecology, but low field seedling emergence from pioneer tree seeds still reduces its large scale applicability. The aim of this research was to evaluate seed priming for the pioneer tree species Guazuma ulmifolia. Priming treatments were selected based on seed hydration curves in water and in PEG 8000 solution. Seeds were primed in water for 16 h and in Polyethylene glycol - PEG 8000 (-0.8 MPa for 56 and 88 h) at 20ºC to reach approximately 30% water content. Half of the seed sample of each treatment was dried back to the initial moisture content (7.2%); both dried and non-dried primed seeds as well as the unprimed seeds (control) were tested for germination (percentage and rate) and vigor (electrical conductivity of seed leachates). Seedling emergence percentage and rate were evaluated under greenhouse conditions, while seedling length and uniformity of seedling development were estimated using the automated image analysis software SVIS®. Primed seeds showed the highest physiological potential, which was mainly demonstrated by image analysis. Fresh or dried primed seeds in water for 16 h and in PEG (-0.8 MPa) for 56 h, and fresh primed seeds in PEG for 88 h, improved G. ulmifolia germination performance. It is suggested that these treatments were promising to enhance efficiency of stand establishment of this species by direct seeding in restoration ecology programs.

A semeadura direta é um dos métodos mais promissores para a restauração ecológica, mas a baixa emergência de plântulas em campo a partir de sementes de árvores pioneiras ainda limita sua aplicabilidade em larga escala. Avaliou-se a resposta de sementes da espécie florestal pioneira Guazuma ulmifolia ao condicionamento fisiológico. Os tratamentos foram selecionados com base em curvas de hidratação em água e em solução osmótica de Polietilenoglicol - PEG 8000. As sementes foram condicionadas em água por 16 h e em PEG 8000 (-0,8 MPa por 56 e 88 h) a 20ºC, atingindo teor de água de, aproximadamente, 30%. Metade das amostras de cada tratamento foi secada até atingir teor de água próximo ao inicial (7,2%); em seguida, avaliou-se o desempenho das sementes condicionadas submetidas ao não à secagem, além de sementes não condicionadas (testemunha), quanto à germinação (porcentagem e velocidade) e o vigor (condutividade elétrica dos exudatos das sementes). A porcentagem e a velocidade de emergência de plântulas foram avaliadas em condições de casa de vegetação, enquanto que o comprimento de plântulas e a uniformidade de desenvolvimento das plântulas foram estimados usando o software de análise computadorizada de imagens de plântulas SVIS®. As sementes condicionadas fisiologicamente apresentaram potencial fisiológico superior, demonstrado principalmente pelos resultados da análise de imagens. Assim, as sementes condicionadas em água durante 16 h ou em PEG durante 88 h, ambas não submetidas à secagem subsequente, e as condicionadas em PEG durante 56 h e submetidas a secagem, beneficiaram o desempenho germinativo de G. ulmifolia. Sugere-se que esses tratamentos são promissores para aumentar a eficiência de estabelecimento de estande dessa espécie via semeadura direta em programas de restauração ecológica.

Physiological potential of cauliflower seeds

The assessment of seed physiological performance is essential to provide consistent information to compose quality control programs conducted by seed companies and allow prompt decisions to reduce post-harvest and commercialization problems. This research was carried to evaluate the efficiency of different procedures to determine cauliflower seed vigor. Six lots of the cultivar Sharon were initially characterized by germination and seedling emergence, and subsequently subjected to traditional and saturated salt accelerated aging, controlled deterioration, electrical conductivity, and potassium leachate tests, in two evaluation times. The traditional accelerated aging (41ºC/48 h), the saturated salt procedure (45ºC/72 h), the controlled deterioration (moisture content adjusted to 20% or 22% and aging at 45ºC/24 h), the electrical conductivity (50 seeds/75 mL water and evaluation after 4 h) and the potassium leakage (25 seeds/50 mL of water and evaluation after 30 min) laboratory tests are sensitive to detect differences in the physiological potential of cauliflower seeds. However, those results did not relate to the percentage seedling emergence in greenhouse controlled conditions, as a consequence of the favorable conditions for emergence. However, the differences identified in the tests may be related to the ability of seed lots to perform in less favorable environments.

A eficiência da determinação do potencial fisiológico de lotes de sementes é essencial para a obtenção de informações consistentes, permitindo a composição de programas de controle de qualidade de sementes e a obtenção de informações consistentes para a redução de problemas pós-colheita e durante a comercialização. O objetivo desta pesquisa foi comparar a eficiência de diferentes procedimentos para a determinação do vigor de sementes de couve-flor. Para tanto, foram utilizados seis lotes do cultivar Sharon, caracterizados inicialmente pelos testes de germinação e de emergência de plântulas. Em seguida, conduziram-se testes de envelhecimento acelerado tradicional e com solução saturada de cloreto de sódio, deterioração controlada, condutividade elétrica e lixiviação de potássio, em duas épocas de avaliação. Os testes de envelhecimento acelerado tradicional, a 41ºC/48 h, e com solução saturada de cloreto de sódio, a 45ºC/72 h, de deterioração controlada (ajuste do grau de umidade para 20% ou 22%, 45ºC/24 h), de condutividade elétrica (combinação 50 sementes/75 mL de água/4 h) e de lixiviação de potássio (25sementes/50 mL de água/30 min) são suficientemente sensíveis para detectar diferenças no potencial fisiológico de sementes de couve-flor. No entanto, essas informações não se refletiram na percentagem de emergência de plântulas em ambiente favorável, mas podem ser úteis para identificar lotes com maior probabilidade de apresentar desempenho adequado quando ocorrem desvios das condições mais adequadas de ambiente.

Physiological potential of cauliflower seeds

The assessment of seed physiological performance is essential to provide consistent information to compose quality control programs conducted by seed companies and allow prompt decisions to reduce post-harvest and commercialization problems. This research was carried to evaluate the efficiency of different procedures to determine cauliflower seed vigor. Six lots of the cultivar Sharon were initially characterized by germination and seedling emergence, and subsequently subjected to traditional and saturated salt accelerated aging, controlled deterioration, electrical conductivity, and potassium leachate tests, in two evaluation times. The traditional accelerated aging (41ºC/48 h), the saturated salt procedure (45ºC/72 h), the controlled deterioration (moisture content adjusted to 20% or 22% and aging at 45ºC/24 h), the electrical conductivity (50 seeds/75 mL water and evaluation after 4 h) and the potassium leakage (25 seeds/50 mL of water and evaluation after 30 min) laboratory tests are sensitive to detect differences in the physiological potential of cauliflower seeds. However, those results did not relate to the percentage seedling emergence in greenhouse controlled conditions, as a consequence of the favorable conditions for emergence. However, the differences identified in the tests may be related to the ability of seed lots to perform in less favorable environments.

A eficiência da determinação do potencial fisiológico de lotes de sementes é essencial para a obtenção de informações consistentes, permitindo a composição de programas de controle de qualidade de sementes e a obtenção de informações consistentes para a redução de problemas pós-colheita e durante a comercialização. O objetivo desta pesquisa foi comparar a eficiência de diferentes procedimentos para a determinação do vigor de sementes de couve-flor. Para tanto, foram utilizados seis lotes do cultivar Sharon, caracterizados inicialmente pelos testes de germinação e de emergência de plântulas. Em seguida, conduziram-se testes de envelhecimento acelerado tradicional e com solução saturada de cloreto de sódio, deterioração controlada, condutividade elétrica e lixiviação de potássio, em duas épocas de avaliação. Os testes de envelhecimento acelerado tradicional, a 41ºC/48 h, e com solução saturada de cloreto de sódio, a 45ºC/72 h, de deterioração controlada (ajuste do grau de umidade para 20% ou 22%, 45ºC/24 h), de condutividade elétrica (combinação 50 sementes/75 mL de água/4 h) e de lixiviação de potássio (25sementes/50 mL de água/30 min) são suficientemente sensíveis para detectar diferenças no potencial fisiológico de sementes de couve-flor. No entanto, essas informações não se refletiram na percentagem de emergência de plântulas em ambiente favorável, mas podem ser úteis para identificar lotes com maior probabilidade de apresentar desempenho adequado quando ocorrem desvios das condições mais adequadas de ambiente.

Métodos alternativos do teste de frio para avaliação do vigor de sementes de milho

This research was conducted with the objective of comparing different procedures of the cold test to evaluate corn seed vigor. Two cultivars (AG 3010 and AG 5011) represented by 5 lots each were used. Seed samples of all lots were submitted to four procedures of the cold test: stacked deep-box (Brazilian traditional method), deep-box disposed side by side, tray with soil and tray with soil + paper towel, in cold chamber at 10°C for seven days followed by germination at 25°C. Those procedures were also compared with germination, accelerated aging and seedling field emergence tests. The cold test in tray exhibited a great level of standardization than the procedure known as deep-box, allowing for more consistent results and a closer relationship to seedling field emergence.

O presente trabalho teve como objetivo básico estudar comparativamente quatro métodos para a condução do teste de frio, visando a avaliação do potencial fisiológico das sementes de milho. Para tanto, foram utilizados dois cultivares de milho (AG 3010 e AG 5011), cada um representado por 5 lotes com potenciais fisiológicos distintos. Amostras de sementes de todos os lotes foram submetidas a quatro procedimentos do teste de frio, a saber: "terra" (mistura de terra e areia) em caixas empilhadas (método tradicional); "terra" em caixas dispostas lado a lado; bandeja com "terra"; bandeja com "terra" + papel toalha. Estes procedimentos foram comparados com os testes de germinação padrão, envelhecimento acelerado e emergência das plântulas em campo. O teste de frio em bandeja oferece maior facilidade para padronização e permite a obtenção de resultados mais consistentes do que o teste de frio utilizando-se "terra" em caixas, inclusive quanto à relação com a emergência das plântulas em campo.

Envelhecimento acelerado e deterioração controlada em sementes de tomate

Tomato seeds have a high commercial value, and the loss of seed physiological quality over time is demonstrated by their low storability unless hermetic conditions are used. As a result the development of satisfactory seed vigor test must be used and intensified. The objective of the present work was to study the accelerated aging and the controlled deterioration to evaluate the physiological quality of tomato seeds. Five seed lots of hybrids Debora Plus and Bruna were submitted to tests of germination, seedling emergence, accelerated aging (periods of 48 and 72 hours, at 38°C or 41°C, with or without the use of saturated solution of NaCl) and controlled deterioration (19%, 21% and 24% water content, at 45°C and 24- and 48-hour periods). Among the adopted procedures the 72h / 41°C / with or without the use of saturated solution of NaCl combination, for the accelerated aging test, and the 24% water / 24h / 45°C combination, for the controlled deterioration test, are efficient to detect vigor differences among tomato seed lots.

Sementes de tomate apresentam alto valor comercial e, por esse motivo, merecem atenção especial quanto ao potencial fisiológico, principalmente devido às dificuldades para o armazenamento; para tanto, estudos dirigidos à determinação do vigor devem ser utilizados e intensificados. Este trabalho teve por objetivo estudar o envelhecimento acelerado e a deterioração controlada para avaliação do potencial fisiológico de sementes de tomate. Para tanto, cinco lotes de sementes, dos híbridos Debora Plus e Bruna, foram submetidos aos testes de germinação, emergência das plântulas em casa de vegetação, envelhecimento acelerado (empregando-se os períodos de 48 e 72 horas, a 38°C ou 41°C, com e sem o uso de solução saturada de NaCl) e deterioração controlada (sementes com graus de umidade de 19%, 21% e 24%, a 45°C, durante 24 e 48 horas). A combinação 72h / 41°C / com ou sem o uso da solução saturada de NaCl, no teste de envelhecimento acelerado, e a combinação 24% de água / 24h / 45°C, no teste de deterioração controlada, são eficientes para detectar diferenças de vigor entre os lotes de sementes de tomate.

Accelerated aging of melon seeds

Accelerated aging is one of the most useful tests used for the evaluation of seed vigor but it is seldomly used to test melon (Cucumis melo L.) seeds. The objective this research was to compare different procedures of the accelerated aging test to evaluate the physiological quality of melon seeds and the efficiency of using saturated salt solution for the control of water uptake by seeds. Five seed lots each of the hybrids AF-646 and AF-682 were tested for germination, seedling emergence, traditional accelerated aging (periods 0f 48, 72 and 96 hours, at 38 or 41°C) and salt saturated accelerated aging. The accelerated aging test (traditional procedure and with salt solution) for 72h and 96h, at 38 or 41°C was sensitive to detect differences in the physiological quality of the seeds. It was also observed that the seed water content after salt saturated accelerated aging was lower and more uniform, thus presenting advantagens in relation to the traditional procedure.

O teste de envelhecimento acelerado é um dos mais utilizados para a avaliação do potencial fisiológico das sementes de várias espécies. Entretanto, estudos com sementes de melão ainda são escassos. Avaliou-se procedimentos para a condução do teste de envelhecimento acelerado para avaliação do potencial fisiológico de sementes de melão (Cucumis melo L.), incluindo o uso de solução saturada de sal em substituição à água. Cinco lotes de sementes, dos híbridos AF-646 e AF-682, foram submetidos aos testes de germinação, emergência de plântulas em casa de vegetação e envelhecimento acelerado (períodos de 48, 72 ou 96 horas, a 38 ou 41°C), com e sem o uso de solução saturada de NaCl. O teste de envelhecimento acelerado (procedimento tradicional e com solução salina), conduzido com períodos de exposição de 72h e 96h a 38 ou 41°C, apresentou sensibilidade suficiente para detectar diferenças no potencial fisiológico de lotes de sementes de melão. A utilização de solução saturada de NaCl contribui para reduzir a absorção de água pelas sementes durante o teste de envelhecimento acelerado, permitiu obter resultados menos drásticos e mais uniformes, sem afetar a eficiência do teste.

Accelerated aging and controlled deterioration for the determination of the physiological potential of onion seeds

International research on vegetable seed vigor is not at the same level attained for grain crops species. This study was conducted to identify reliable procedures for the accelerated aging and controlled deterioration tests to rank onion (Allium cepa L.) seed lots according to their physiological potential. Six seed lots of the cultivars Aurora and Petroline were evaluated in the laboratory for germination, first count, seedling vigor classification, traditional and saturated salt accelerated aging (41ºC / 48 and 72 h), controlled deterioration (24% of water / 45ºC / 24 h) and seedling emergence tests. Seed moisture content after the saturated salt accelerated aging test was lower and uniform, which is considered an important advantage in comparison to the traditional procedure. The saturated salt accelerated aging (41ºC / 48 and 72 h) and controlled deterioration (moisture content adjusted to 24% / 45ºC / 24 h) tests were the best procedures to assess the physiological potential of onion seeds, and are indicated for use in quality control programs.

Estudos sobre testes para avaliação do potencial fisiológico de sementes de hortaliças têm sido menos freqüentes que os conduzidos com as de grandes culturas, tanto no Brasil como no exterior. O presente trabalho teve como objetivo avaliar a eficiência de diferentes procedimentos para a condução dos testes de envelhecimento acelerado e de deterioração controlada na determinação do potencial fisiológico de sementes de cebola. Seis lotes de sementes dos cultivares Aurora e Petroline foram submetidos aos testes de germinação, primeira contagem de germinação, classificação do vigor de plântulas, envelhecimento acelerado tradicional e com uso de solução saturada de NaCl (41ºC/48 e 72 horas), deterioração controlada (24% de água/45ºC/24 horas) e emergência de plântulas em casa de vegetação. O grau de umidade das sementes expostas à solução salina, menor e mais uniforme após os períodos de envelhecimento, constitui importante vantagem na utilização desse procedimento, em relação ao tradicionalmente utilizado para a condução desse teste. Os testes de envelhecimento acelerado com solução saturada de NaCl (41ºC/72 horas) e de deterioração controlada (24% de água/45ºC/24 horas) foram considerados eficientes para avaliação do potencial fisiológico de sementes de cebola, sendo indicados para utilização em programas de controle de qualidade.

Accelerated aging and controlled deterioration for the determination of the physiological potential of onion seeds

International research on vegetable seed vigor is not at the same level attained for grain crops species. This study was conducted to identify reliable procedures for the accelerated aging and controlled deterioration tests to rank onion (Allium cepa L.) seed lots according to their physiological potential. Six seed lots of the cultivars Aurora and Petroline were evaluated in the laboratory for germination, first count, seedling vigor classification, traditional and saturated salt accelerated aging (41ºC / 48 and 72 h), controlled deterioration (24% of water / 45ºC / 24 h) and seedling emergence tests. Seed moisture content after the saturated salt accelerated aging test was lower and uniform, which is considered an important advantage in comparison to the traditional procedure. The saturated salt accelerated aging (41ºC / 48 and 72 h) and controlled deterioration (moisture content adjusted to 24% / 45ºC / 24 h) tests were the best procedures to assess the physiological potential of onion seeds, and are indicated for use in quality control programs.

Estudos sobre testes para avaliação do potencial fisiológico de sementes de hortaliças têm sido menos freqüentes que os conduzidos com as de grandes culturas, tanto no Brasil como no exterior. O presente trabalho teve como objetivo avaliar a eficiência de diferentes procedimentos para a condução dos testes de envelhecimento acelerado e de deterioração controlada na determinação do potencial fisiológico de sementes de cebola. Seis lotes de sementes dos cultivares Aurora e Petroline foram submetidos aos testes de germinação, primeira contagem de germinação, classificação do vigor de plântulas, envelhecimento acelerado tradicional e com uso de solução saturada de NaCl (41ºC/48 e 72 horas), deterioração controlada (24% de água/45ºC/24 horas) e emergência de plântulas em casa de vegetação. O grau de umidade das sementes expostas à solução salina, menor e mais uniforme após os períodos de envelhecimento, constitui importante vantagem na utilização desse procedimento, em relação ao tradicionalmente utilizado para a condução desse teste. Os testes de envelhecimento acelerado com solução saturada de NaCl (41ºC/72 horas) e de deterioração controlada (24% de água/45ºC/24 horas) foram considerados eficientes para avaliação do potencial fisiológico de sementes de cebola, sendo indicados para utilização em programas de controle de qualidade.

Accelerated aging of melon seeds

Accelerated aging is one of the most useful tests used for the evaluation of seed vigor but it is seldomly used to test melon (Cucumis melo L.) seeds. The objective this research was to compare different procedures of the accelerated aging test to evaluate the physiological quality of melon seeds and the efficiency of using saturated salt solution for the control of water uptake by seeds. Five seed lots each of the hybrids AF-646 and AF-682 were tested for germination, seedling emergence, traditional accelerated aging (periods 0f 48, 72 and 96 hours, at 38 or 41°C) and salt saturated accelerated aging. The accelerated aging test (traditional procedure and with salt solution) for 72h and 96h, at 38 or 41°C was sensitive to detect differences in the physiological quality of the seeds. It was also observed that the seed water content after salt saturated accelerated aging was lower and more uniform, thus presenting advantagens in relation to the traditional procedure.

O teste de envelhecimento acelerado é um dos mais utilizados para a avaliação do potencial fisiológico das sementes de várias espécies. Entretanto, estudos com sementes de melão ainda são escassos. Avaliou-se procedimentos para a condução do teste de envelhecimento acelerado para avaliação do potencial fisiológico de sementes de melão (Cucumis melo L.), incluindo o uso de solução saturada de sal em substituição à água. Cinco lotes de sementes, dos híbridos AF-646 e AF-682, foram submetidos aos testes de germinação, emergência de plântulas em casa de vegetação e envelhecimento acelerado (períodos de 48, 72 ou 96 horas, a 38 ou 41°C), com e sem o uso de solução saturada de NaCl. O teste de envelhecimento acelerado (procedimento tradicional e com solução salina), conduzido com períodos de exposição de 72h e 96h a 38 ou 41°C, apresentou sensibilidade suficiente para detectar diferenças no potencial fisiológico de lotes de sementes de melão. A utilização de solução saturada de NaCl contribui para reduzir a absorção de água pelas sementes durante o teste de envelhecimento acelerado, permitiu obter resultados menos drásticos e mais uniformes, sem afetar a eficiência do teste.