Navegando por Autor "Dias, Denise Cunha Fernandes dos Santos"
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Item Accelerated ageing test to evaluate vigour in Jatropha curcas L. seeds(Revista Ciência Agronômica, 2013-10-08) Dias, Luiz Antônio dos Santos; Oliveira, Glauter Lima; Dias, Denise Cunha Fernandes dos Santos; Soares, Marcos Morais; Silva, Laércio Junio daThere is currently great interest in the cultivation of the Jatropha curcas L., known locally as physic nut, for the production of biodiesel, leading to an increase in the demand for seeds and precise information as to their physiological quality, especially vigour. The objective was to evaluate the efficiency of the accelerated ageing test, with variations, in verifying the vigour of Jatropha seeds. Four seed lots were initially characterized as to their physiological quality by germination and vigour tests. For accelerated ageing test, temperatures of 42 and 45 oC were tested during 48, 72 and 96 hours. The experiment was carried out in a completely randomized design and the averages of the treatments compared by Tukey test (p<0,05). The Pearson correlation coefficients for the results of accelerated ageing against results from the other tests were calculated. The accelerated ageing test at 42 or 45 oC for 48 hours is efficient to classify Jatropha seed lots according to vigour level.Item Ajuste de metodologias para a identificação de cultivares de soja quanto à tolerância ao glifosato(Revista Brasileira de Sementes, 2009) Pereira, Welison Andrade; Lisboa, Suzana Patrícia; Dias, Denise Cunha Fernandes dos Santos; Alvarenga, Eveline Mantovani; Borém, AluízioOs bioensaios constituem numa alternativa prática e eficiente para detecção de sementes de soja geneticamente modificada (GM), tolerante ao glifosato. Contudo, deve ser verificada sua utilização na identificação das sementes quando o lote é de soja GM, ou seja, quando sementes de soja convencional são a minoria. Objetivou-se com este trabalho ajustar a metodologia de dois bioensaios de detecção de sementes de soja GM e testar os melhores protocolos, um de cada bioensaio, na detecção e quantificação de misturas simuladas, contendo genótipos contrastantes quanto à tolerância ao herbicida. Nos bioensaios, foram testadas três umidades do substrato (2,0; 2,5 e 3,0 vezes o seu peso seco), cinco soluções do herbicida (0; 0,01; 0,03; 0,06 e 0,12 %) no método papel umedecido com glifosato e quatro soluções (0; 0,3; 0,6 e 1,2 %) no método pré - embebição de sementes. A umidade 3,0 e solução 0,03 % constituíram o protocolo mais eficiente para detecção no método do papel umedecido. A umidade 2,0 e solução 0,3 % se destacaram no método da pré-embebição das sementes. Foi mais prático e rápido detectar plântulas tolerantes do que plântulas sensíveis em ambos os testes. Em amostras com maior taxa de contaminação, foi mais fácil detectar e mais difícil quantificar misturas com exatidão. Os erros foram relativamente raros considerando os acertos.Item Biochemical and physiological analysis in carrot seeds from different orders of umbels(Revista Ciência Agronômica, 2016-04) Silva, Patrícia Pereira da; Sekita, Marcelo Coelho; Dias, Denise Cunha Fernandes dos Santos; Nascimento, Warley MarcosIn carrot seed production, harvesting of the umbels is generally staggered, or sometimes the whole plant is harvested with the umbels at different stages of maturation; in that case, there is a risk of harvesting immature seeds and of losses due to natural dehiscent, or to physiological deterioration as a result of unfavourable environmental factors. The present study aimed to evaluate the physiological and biochemical changes related to the maturation of 'Planalto' carrot seeds from diferent umbels. The samples were collected 120 days after anthesis, with the primary, secondary and tertiary umbels being harvested separately. Seeds were analysed for germination, first count and germination rate, at temperatures of 25 ºC (optimum) to 35 ºC (adverse), as well as for emergence in the greenhouse and the emergence rate. Analyses were also carried out of the enzymes peroxidase (POX), ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD), and of the total protein. Seeds obtained from the primary and secondary umbels displayed a higher rate of germination than from the tertiary umbels, with the seeds from the primary umbels showing high activity for peroxidase, catalase and superoxide dismutase, and low activity for the enzyme ascorbate peroxidase.Item Biochemical changes in hybrid pumpkin seeds at different stages of maturation(Revista Ciência Agronômica, 2017-07) Dias, Denise Cunha Fernandes dos Santos; Silva, Patrícia Pereira da; Barros, Antonio Carlos Souza Albuquerque; Sekita, Marcelo Coelho; Nascimento, Warley MarcosThis study aimed to evaluate biochemical changes in seeds of the pumpkin hybrid, 'Jabras', from fruit harvested at different stages of maturation (15, 30, 45, 60 and 75 days after anthesis). Thirty fruit were harvested at each stage, with the seeds from 15 of the fruit being extracted immediately. The remaining 15 were stored for twenty days in plastic boxes and the seeds extracted after this period. After processing and drying the seeds, the following were determined: moisture content, germination, first count and antioxidant enzyme activity (peroxidase, ascorbate peroxidase, catalase and superoxide dismutase). Seeds from the fruit harvested at 30 DAA displayed low values for germination and vigour and high antioxidant enzyme activity, indicating that they were immature and that drying possibly caused damage to the system of cell membranes. The results obtained in this study demonstrated that analysis related to changes in the activity of enzymes during development and maturation of the seeds was effective in evaluating the physiological and biochemical changes in pumpkin seeds of the 'Jabras' cultivar.Item Efeito da aplicação de silicato de cálcio e de cinza de casca de arroz sobre a incidência de fungos associados a manchas em sementes de arroz irrigado(Summa Phytopathologica, 2016-01) Roma-Almeida, Rafaela Carolina Constantino; Pereira, Olinto Liparini; Dias, Denise Cunha Fernandes dos Santos; Rodrigue, Fabrício Ávila; Prabhu, Anne Sitarama; Filippi, Marta Cristina Corsi de; Duarte, Henrique da Silva SilveiraO objetivo deste trabalho foi avaliar o efeito da aplicação de silicato de cálcio e de cinza de casca de arroz (CCA) na incidência de fungos associados a manchas em sementes de arroz irrigado. Plantas de arroz foram submetidas à aplicação de silicato de cálcio ou CCA nas doses de 0, 51, 153, 256 e 357 kg ha-1de silício (Si). Dois experimentos foram conduzidos, sendo um na safra 2007/2008 e outro na safra 2008/2009 e, posteriormente, amostras de sementes foram analisadas em laboratório. Foram realizadas avaliações do Índice de Escurecimento de Sementes (IES), da concentração de Si no pericarpo das sementes e a determinação da diversidade dos fungos presentes nas sementes. Não houve efeito das duas fontes de Si empregadas, nas doses utilizadas nos dois experimentos no IES e na concentração de Si. Os fungos fitopatogênicos encontrados em ambos experimentos foram Alternaria padwickiii, Bipolarisoryzae, Botrytis cinerea, Curvularia lunata, Fusarium semitectum, F. solani, Microdochium oryzae, Nigrospora oryzae, Phoma sorghina e Pyriculariaoryzae. A incidência destes fungos não foi afetada pela aplicação das fontes de Si nas doses utilizadas.Item Effect of cyanide by sodium nitroprusside (SNP) application on germination, antioxidative system and lipid peroxidation of Senna macranthera seeds under saline stress(Journal of Seed Science, 2019-01) Silva, Aparecida Leonir da; Pinheiro, Daniel Teixeira; Borges, Eduardo Euclydes de Lima e; Silva, Laércio Junio da; Dias, Denise Cunha Fernandes dos SantosThe effects of NO donors on germination under saline stress have been much investigated for many species, however, there are reports that the effect caused by donors are effects of cyanide present. The aim of this study was to evaluate the effects of sodium nitroprusside (SNP) on germination, antioxidative system and lipid peroxidation of Senna macranthera seeds under saline stress. The osmotic potentials of -0.4 and -0.5 MPa of NaCl were used, as well as the concentration of 100 μM of sodium nitroprusside, inactive sodium nitroprusside. Germination rate, imbibition curves, antioxidant enzyme activity, lipid peroxidation, and protein content were evaluated. Similar effects were observed for sodium nitroprusside and inactive sodium nitroprusside, indicating that these effects were related to the release of the cyanide present in sodium nitroprusside. The sodium nitroprusside (SNP) improves the germination of Senna macranthera seeds under salt stress conditions, through release of cyanide. The cyanide favored germination, reducing lipid peroxidation and increasing the activity of the antioxidant enzymes.Item The effect of fruit maturity on the physiological quality and conservation of Jatropha curcas seeds(Revista Ciência Agronômica, 2017-07) Silva, Laércio Junio da; Dias, Denise Cunha Fernandes dos Santos; Oliveira, Glauter Lima; Silva Júnior, Rubens Alves daThe aim of this study was to evaluate the effect of fruit maturation stage on the physiological quality of J. curcas seeds during storage. Thus, seeds were extracted from fruits harvested at different maturity stages based on external color, i.e., yellow, yellow-brown and brown (dry fruits). After natural drying, the seeds were packed in Kraft paper bag and stored for 18 months at laboratory environment. Initially and every three months, the seeds were evaluated for moisture content, germination, first count of germination, accelerated aging, cold test, electrical conductivity and emergence. There was reduction in seed physiological quality, with decrease in germination and vigor, especially after nine months of storage. The seeds extracted from yellow and yellow-brown fruits are the most vigorous and can be stored for up to nine months without loss of physiological quality.Item Effect of sodium nitroprusside (SNP) on the germination ofSenna macranthera seeds (DC. ex Collad.) H. S. Irwin & Baneby under salt stress(Journal of Seed Science, 2015-10) Silva, Aparecida Leonir da; Dias, Denise Cunha Fernandes dos Santos; Borges, Eduardo Euclydes de Lima e; Ribeiro, Dimas Mendes; Silva, Laércio Junio daNitric oxide (NO) has been used as stimulating of the germination process for many species. However, there are few studies evaluating the effect of nitric oxide donor in the regulation of seed germination under salt stress, especially for native forest species. The objective was to evaluate the effects of SNP, an NO donor substance, on germination of Senna macranthera seeds under salt stress. The seeds were germinated at different osmotic potentials induced by NaCl solution (0.0, -0.1, -0.2, -0.3, -0.4 and -0.5 MPa). To evaluate the effect of the SNP, potentials -0.3 and -0,4 MPa were selected, applying SNP at different concentrations: 100, 200, 300 and 400 µM. Germination tests were conducted at 25 °C, with photoperiod of 8 hours. Percentage of radicle protrusion, radicle protrusion speed index, percentage of normal seedlings, shoots and roots length and dry matter were evaluated. Salt stress with NaCl is harmful to germination of S. macranthera seeds. SNP has the potential to recover germination under salt stress, especially in the concentration of 100 µM.Item Exudate coloring test suitability for assessing the viability of coffee seeds (Coffea arabica L.)(Journal of Seed Science, 2016-07) Hilst, Paulo César; Dias, Denise Cunha Fernandes dos Santos; Gama, Guilherme Fontes Valory; Araújo, Joyce de OliveiraThe exudate coloring test has been promising in order to quickly evaluate the quality of coffee seeds. The objective of the research was to adjust the coloring exudate test for coffee seeds and to evaluate the influence of the water content of seeds and of the imbibition period on the test results. Seeds from five lots of 'Catuaí 44' were used, with the following water contents: 30%, 20% and 12%. For the exudate coloring test, the parchment and silver skin (spermoderm) from the seeds were removed. Then, the seeds were distributed on a paper towel, moistened with water, and kept in a germinator at 25 °C for 24, 48, 72, 96 and 120 h. Four classes of coloring intensity were established: absence of color (A), light (L), medium (M) and strong (S) intensities, assigning the values 0, 3, 5 and 10 for each class, respectively. The Viability Index (VI) was calculated by the equation VI=100-(0xA)-(3xL)-(5xM)-(10xS). The exudate coloring test may be recommended to estimate the viability of coffee seeds, providing results correlated to the germination test. The best results were obtained for the seeds with 12% moisture content imbibed for 72, 96 and 120 h and seeds with 30% moisture content after 72 and 120 h of imbibition.Item Fluxo gênico em soja geneticamente modificada e método para sua detecção(Pesquisa Agropecuária Brasileira, 2017-07) Pereira, Welison Andrade; Del Giúdice, Marcos Paiva; Carneiro, José Eustáquio de Souza; Dias, Denise Cunha Fernandes dos Santos; Borém, AluízioO objetivo deste trabalho foi avaliar métodos para detecção de sementes de soja tolerante ao glifosato e o fluxo gênico de uma cultivar transgênica para uma convencional, em Florestal e Viçosa, MG. Para adequar método de detecção, foi conduzido experimento comparativo entre cinco bioensaios, dos quais se destacou o teste de germinação em substrato umedecido com solução do glifosato. O experimento de fluxo gênico foi instalado em campo, no esquema de quadrados concêntricos. No centro, foi plantada a cultivar tolerante ao glifosato (fonte de pólen). À sua volta, foi semeada a cultivar sensível (receptora do pólen). No estádio R8, foram colhidas sementes das laterais dos quadrados, em distâncias variadas da fonte de pólen: 0,5, 1, 2, 4 e 8 m. Amostras de 900 sementes, por fileira, foram avaliadas pelo teste de germinação em substrato umedecido com solução de glifosato a 0,06%. Plântulas tolerantes ao glifosato indicaram fecundação cruzada. As maiores porcentagens de hibridação – 1,27% em Florestal e 0,25% em Viçosa – ocorreram a 0,5 m de distância, entre fonte e receptor de pólen, e essas taxas aproximaram-se de zero às distâncias de 2,26 e 1,16 m, para Florestal e Viçosa, respectivamente.Item Fluxo gênico recíproco entre cultivares de soja convencional e geneticamente modificada(Pesquisa Agropecuária Brasileira, 2012-01-19) Pereira, Welison Andrade; Sávio, Filipe Luis; Dias, Denise Cunha Fernandes dos Santos; Cruz, Cosme Damião; Borém, AluízioO objetivo deste trabalho foi determinar o fluxo gênico recíproco entre duas cultivares de soja, uma tolerante e outra sensível ao glifosato, além de aplicar estimadores para determinar a taxa de fecundação cruzada na população e o número de sementes híbridas na progênie. O experimento compôs-se de quatro blocos com 40 fileiras de soja, com 20 fileiras de cada cultivar (CD217 e CD219RR). No estádio R8, cinco fileiras, distantes 0, 5, 1, 2, 4 e 8 m da cultivar adjacente, foram colhidas, trilhadas e analisadas quanto à ocorrência de fluxo gênico. Como características marcadoras, foram utilizadas as cores da flor, hipocótilo e pubescência, e a tolerância ao glifosato. As cultivares contrastam quanto às características analisadas, cada uma condicionada por um gene com dois alelos, em interação de dominância completa. Na progênie da cultivar tolerante, a maior taxa de híbridos encontrada foi 0, 27% e, na progênie da cultivar sensível, identificou-se 0, 83%; pela hipótese do efeito diluição, as taxas de hibridação natural populacional seriam 0, 104 e 0, 388%, respectivamente. O fluxo gênico recíproco entre as cultivares CD217 e CD219RR não é o mesmo em ambas as direções. Os estimadores propostos são úteis para determinar a taxa de híbridos em amostras de sementes.Item Genetic divergence between passion fruit hybrids and reciprocals based on seedling emergence and vigor(Journal of Seed Science, 2017-10) Rosado, Renato Domiciano Silva; Rosado, Luciana Domiciano Silva; Santos, Carlos Eduardo Magalhães dos; Dias, Denise Cunha Fernandes dos Santos; Cruz, Cosme Damião; Cremasco, João Paulo GavaCharacteristics related to seed quality have been rarely used in studies on the genetic diversity of passion fruit. The purpose of this study was to evaluate the genetic diversity between progenies constituted by hybrids and reciprocals, based on seed emergence and vigor traits. On the 28th day, emergence percentage, emergence speed index, shoot length, root length and total length of seedling; dry weight, number of normal seedlings and 100-seed weight were evaluated in a completely randomized design experiment with 20 progenies (hybrids and reciprocals) and four replications (50 seeds). Genetic diversity was determined using the Tocher optimization clustering methods and the unweighted pair group method, based on the Mahalanobis distance, as well as evaluating the relative contribution of the traits to genetic divergence and the correlation network, according to the relations between groups of quality, length and mass variables. The most contributing variable to genetic divergence was the total length of seedlings, the reciprocal effect did not present a consistent pattern in the studied hybrid combinations.Item Genetic divergence between passion fruit hybrids and reciprocals based on seedling emergence and vigor(Journal of Seed Science, 2017-10) Rosado, Renato Domiciano Silva; Rosado, Luciana Domiciano Silva; Santos, Carlos Eduardo Magalhães dos; Dias, Denise Cunha Fernandes dos Santos; Cruz, Cosme Damião; Cremasco, João Paulo GavaCharacteristics related to seed quality have been rarely used in studies on the genetic diversity of passion fruit. The purpose of this study was to evaluate the genetic diversity between progenies constituted by hybrids and reciprocals, based on seed emergence and vigor traits. On the 28th day, emergence percentage, emergence speed index, shoot length, root length and total length of seedling; dry weight, number of normal seedlings and 100-seed weight were evaluated in a completely randomized design experiment with 20 progenies (hybrids and reciprocals) and four replications (50 seeds). Genetic diversity was determined using the Tocher optimization clustering methods and the unweighted pair group method, based on the Mahalanobis distance, as well as evaluating the relative contribution of the traits to genetic divergence and the correlation network, according to the relations between groups of quality, length and mass variables. The most contributing variable to genetic divergence was the total length of seedlings, the reciprocal effect did not present a consistent pattern in the studied hybrid combinations.Item Germinação e vigor de sementes de cenoura osmocondicionadas em papel umedecido e solução aerada(Revista Brasileira de Sementes, 2008) Pereira, Márcio Dias; Dias, Denise Cunha Fernandes dos Santos; Dias, Luiz Antonio dos Santos; Araújo, Eduardo FontesNa cultura da cenoura são constantes os problemas relativos ao desempenho das sementes no campo, justificando-se o uso de técnicas que acelerem a germinação das sementes e a emergência das plântulas. O objetivo do trabalho foi avaliar o efeito do condicionamento osmótico na germinação e no vigor de sementes de cenoura, utilizando-se dois métodos de embebição. Para tanto, sementes de dois lotes, cv. Brasília, foram condicionadas em soluções de PEG 6000 a -1,0 e -1,2 MPa por quatro e oito dias, a 20ºC, utilizando-se dois métodos: embebição em papel toalha umedecido com as respectivas soluções e imersão em soluções osmóticas aeradas. Sementes não condicionadas foram utilizadas como testemunha. Após, as sementes condicionadas ou não, foram avaliadas por meio dos testes: de germinação, primeira contagem de germinação, emergência das plântulas em campo aos 10 e 25 dias após a semeadura e comprimento de raiz primária. Verificou-se que o condicionamento osmótico em PEG 6000 por quatro dias foi efetivo em aumentar a porcentagem e a velocidade de germinação, bem como a emergência das plântulas em campo. Para o crescimento da raiz primária, o condicionamento osmótico em solução aerada em PEG 6000 a -1,2MPa foi superior ao tratamento em papel.Item Germination and antioxidant action in melon seeds exposed to salt stress(Pesquisa Agropecuária Tropical, 2016-09) Pinheiro, Daniel Teixeira; Silva, Aparecida Leonir da; Silva, Laércio Junio da; Sekita, Marcelo Coelho; Dias, Denise Cunha Fernandes dos SantosSalinity influences all germination stages and may adversely affect the seedlings establishment in the field. This study aimed at assessing the effects of salt stress on the physiological potential of melon (Cucumis melo L.) seeds. Germination and activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) enzymes were assessed at the osmotic potentials of 0.0 MPa, -0.1 MPa, -0.2 MPa, -0.3 MPa, -0.4 MPa and -0.5 MPa. The enzymatic activity was assessed after 24 h, 48 h and 72 h of imbibition. Seed germination was zero at -0.5 MPa and 91 % and 85 % at -0.1 MPa and -0.2 MPa, respectively. In general, the activity of SOD, CAT and POX enzymes increased with the salt-induced stress, in the different times of imbibition, and these increases were more evident at -0.4 MPa and -0.5 MPa. The salt stress induced by NaCl diminishes the germination rate of melon seeds, particularly from the osmotic potential of -0.2 MPa. There is a significant increase in the activity of SOD, CAT and POX enzymes, mainly after 48 h of exposure.Item Germination and biochemical changes in ‘Formosa’ papaya seeds treated with plant hormones(Acta Scientiarum. Agronomy, 2014-10) Zanotti, Rafael Fonsêca; Dias, Denise Cunha Fernandes dos Santos; Barros, Raimundo Santos; DaMatta, Fábio Murilo; Oliveira, Glauter LimaThis study aimed to investigate the effects of growth regulators on germination rates and biochemical compound concentrations in Carica papaya L. seeds (‘Formosa’ group). The seeds were harvested from fruits at maturation stages 3 and 5 (50 and 75% yellow fruit skin, respectively). The effects of 2-chloroethylphosphonic acid (CEPA), KNO 3 and gibberellic acid (GA 3 ) on seed germination, germination index speed, soluble sugars, starch, lipids, soluble proteins and total proteins of the papaya seeds were evaluated. The seeds from stage 5 showed a higher rate of germination 30 days after sowing than did the seeds from stage 3. Treatment with CEPA decreased seed germination, apparently due to decreased starch mobilization; the opposite response was observed following KNO 3 treatment. GA 3, alone or in combination with KNO 3, stimulated an increase in lipid mobilization. In general, with the exception of CEPA, all growth regulators tested were effective in overcoming seed dormancy, and KNO 3 was the most effective. The seeds from stage 3 fruits treated with KNO 3 or KNO 3 + GA 3 had higher rates of germination at 14 days.Item Germination of "Solo" papaya seeds treated with plant hormones(Journal of Seed Science, 2014) Zanotti, Rafael Fonsêca; Dias, Denise Cunha Fernandes dos Santos; Barros, Raimundo Santos; Silva, Laércio Junio da; Sekita, Marcelo CoelhoThe aim of this study was to investigate the effects of some plant hormones on germination of Carica papaya L. seeds of the "Solo" group taken from fruits at maturity stages 3 and 5 (50% and 75% of the fruit skin showing a yellow color). Then, the seeds were subjected to treatments involving different combinations of acid 2-chloroethylphosphonic - (CEPA 0; 5 x 10-7 and 5 x 10-4 M), GA3 (0; 10 and 50 mg / L) and KNO3 (0 or 1 M), and germination was assessed at the 14th and 30th days. Seeds from fruits at maturity stage 3 showed increased germination when treated with all growth regulators tested. KNO3 promoted a decrease in germination and in the germination speed index, especially in the seeds from stage 5. The plant hormones did not promote any increase in percentage of normal seedlings of papaya seeds. Two-Chloethylphosphonic acid (5 x 10-4 M) and the gibberellic acid applied alone in the seeds from satge 3 promoted an increase in the number of normal seedlings 14 days after sowing.Item Growth retardants in wheat and its effect in physiological quality of seeds(Ciência Rural, 2010-06) Souza, Leandro Torres de; Espíndula, Marcelo Curitiba; Rocha, Valterley Soares; Dias, Denise Cunha Fernandes dos Santos; Souza, Moacil Alves dePlant lodging in wheat has been controlled through growth retardants. However, there is lack of information on the effect of these products on the physiological quality of seeds. The objective of this study was to evaluate the physiological quality of wheat seeds obtained under different rates and application times of three growth retardants. The trial was carried out in Viçosa-MG, from May to September 2005, in a factorial and hierarchical scheme, in randomized block design with four replications and a control treatment. The treatments consisted of 500, 1000 and 1500g ha-1 of chlormequat; 40, 80 and 120g ha-1 of paclobutrazol and 62.5, 125 and 187.5g ha-1 of trinexapac-ethyl applied at the 6 or 8 growth stage based on the scale of Feeks and Large, and a control treatment without growth retardant application. Leaf application of growth retardants as chlormequat, paclobutrazol and trinexapac-ethyl did not affect the germination and vigor of wheat seeds.Item Hydration of carrot seeds in relation to osmotic potential of solution and conditioning method(Revista Brasileira de Sementes, 2007-06-29) Pereira, Márcio Dias; Dias, Denise Cunha Fernandes dos Santos; Dias, Luiz Antonio dos Santos; Araújo, Eduardo FontesThe objective of this study was to monitor carrot seed hydration in water and osmotic solutions to define appropriate conditions for priming treatment. Two Brasília cultivar carrot seed lots were used. Seeds were imbibed in -1.0 and -1.2 MPa PEG 6000 osmotic solutions and in distilled water, in an incubator BOD at 20ºC, using two different hydration methods: imbibition in moistened paper towel sheets and in aerated solutions. The imbibition curves for each seed lot were drawn after determining seed moisture content at 2, 4, 6, 8, 10, 12, 24, 48, 72, 96 hours hydration in water and after 2, 4, 6, 8, 10, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, 264, 312 hours hydration in PEG 6000 solutions. Seed hydration in distilled water was faster than in PEG 6000 solutions; the primary root protrusion occurred at 48 hours imbibition as seeds reached 54% moisture content. Osmotic conditioning of carrot seeds should be performed by imbibition in PEG 6000 -1.0 or -1.2 MPa solutions to attain 40% and 45% moisture content (moistened paper) or 40% and 45% (aerated solutions).Item Influence of seed size and water restriction on germination of soybean seeds and on early development of seedlings(Journal of Seed Science, 2013) Pereira, Welison Andrade; Pereira, Sara Maria Andrade; Dias, Denise Cunha Fernandes dos SantosGermination is a biological process that depends on adequate water supply to embryo development. Water deficit slows this process and depending on intensity and extent of this deficit may cause seed death. Nevertheless, it has not yet been reported whether seed size influences physiological potential, or tolerance to water stress. This study aimed at assessing the effects of seed size, as well as of water stress on germination of the seeds and on early soybean seedling development. The experiment was composed by seeds of 10 soybean cultivars classified by metallic screens with three sizes of oval holes (S12, S13 and S14) and subjected to three water potentials (0, -0.1, and -0.2 MPa), with four replications. Data on genotypes were grouped as replications and arranged on a factorial 3 x 3 (size x water potential), with 40 replications. Data assessed were: first and final count of germination; length and seedling dry weight; and correlation between length/mass of radicle and hypocotyl. It was concluded that under ideal moisture conditions larger seeds have better physiological quality, producing more vigorous seedlings; but, that under water potential of -0.2 MPa smaller seeds produce larger seedlings; and that the hypocotyl is more influenced by water stress than the radicle.