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Psychotria hoffmansegiana (Willd ex Roem. & Schult.) Mull. Arg. and Palicourea marcagravii st. Hil. (Rubiaceae): potential for forming soil seed banks in a brazilian Cerrado

Araújo, CG.; Cardoso, VJM.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: 421-427
ENG
Relevância na Pesquisa
36.57%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Observou-se a germinabilidade de sementes de Psychotria hoffmansegiana e Palicourea marcagravii enterradas em solo de Cerrado, buscando-se avaliar o potencial de formação de banco de sementes no solo. Ensaios foram realizados em uma Reserva de Cerrado, São Paulo, Brasil. Amostras de sementes foram colocadas em sacos de tela de nylon e enterradas em duas profundidades, e em dois ambientes. Amostras eram periodicamente desenterradas e submetidas a teste de germinação, juntamente com sementes armazenadas em laboratório. em geral, o armazenamento no solo favoreceu a sobrevivência e a capacidade de germinação das sementes, em comparação com sementes armazenadas em laboratório. A germinação foi pouco afetada pela profundidade de enterramento e pelo ambiente. Sementes de ambas as espécies conservaram a viabilidade por 13 meses, considerando-se o período entre a coleta e o final dos testes de germinação. É sugerido que ambas as espécies são potencialmente capazes de formar banco de sementes persistente no solo do Cerrado.; The germinability of artificially buried Psychotria hoffmansegiana and Palicourea marcagravii seeds in Cerrado soil was tested...

Thermal-biological aspects on the seed germination of Cucumis anguria L.: influence of the seed coat

SANTOS, DÉBORA LEONARDO DOS; CARDOSO, VICTOR JOSÉ MENDES
Fonte: Sociedade Botânica de São Paulo Publicador: Sociedade Botânica de São Paulo
Tipo: Artigo de Revista Científica Formato: 435-440
ENG
Relevância na Pesquisa
36.53%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); O tegumento pode influenciar a germinação e a dormência de sementes. Trabalhos anteriores mostram que a testa influencia a resposta germinativa de sementes de Cucumis anguria à luz, embora a influência do tegumento na resposta à temperatura ainda não esteja bem estabelecida. O principal objetivo deste estudo foi observar a influência da testa na germinação de C. anguria, usando-se como parâmetros a germinabilidade e a taxa de germinação isotérmica. Os ensaios foram realizados em bloco de gradiente térmico, em condições de escuro constante. Estimativas da entalpia de ativação (deltaH) mostram |deltaH | < 50 kJ.mol-1 entre 26,1 °C e 35,2 °C (sementes intatas) e entre 25,4 °C e 35,2 °C (sementes escarificadas), e sugerem a ocorrência de processos com |deltaH | > 125 kJ.mol-1 em temperaturas acima de 35,2 °C. Os resultados sugerem que a testa pode limitar a expansão de embrião, não interferindo em processos de difusão.; The seed coat influences the early stages of germination of many seeds and sometimes maintains seed dormancy. Early reports have shown that the testa influences the germination response of Cucumis anguria seeds to light although the response to temperature as influenced by the tegument is not well understood. The main purpose of this study was to observe the influence of the testa on the germination of Cucumis anguria by using parameters as germinability and isothermal germination rate. The assays were carried out in a thermal-gradient block with water imbibed seeds kept in darkness. Estimates of the activation enthalpies (deltaH) show |deltaH| < 50 kJ.mol-1 between 26.1 °C and 35.2 °C (intact seeds) and between 25.4 °C and 35.2 °C (scarified seeds)...

Temperature effect on seed germination in Canna indica L. (Cannaceae)

Souza Filho, P. R. M.; Tozzi, H. H.; Takaki, M.
Fonte: Ista-int Seed Testing Assoc Publicador: Ista-int Seed Testing Assoc
Tipo: Artigo de Revista Científica Formato: 243-247
ENG
Relevância na Pesquisa
46.49%
Comm indica L. is an herbaceous species with ornamental and medicinal value, having seeds with a hard seed coat. This study aimed to test the influence of constant temperatures ranging from 5 to 45 C, at 5 C intervals, on the germination of scarified seeds. Data obtained were analyzed through the model of enthalpy of activation in order to obtain the optimum temperature range for germination. The species showed seed germinability in a wide temperature range (10-40 degrees C) being the optimal temperature range between 13.84 and 34.41 degrees C, determined by the enthalpy of activation.

Frugivory and the effects of ingestion by bats on the seed germination of three pioneering plants

Carvalho-Ricardo, Maria C. de; Uieda, Wilson; Fonseca, Renata Cristina B.; Rossi, Marcelo N.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 51-57
ENG
Relevância na Pesquisa
46.86%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The dispersion and seedling establishment of pioneering plants can be favoured by the presence of frugivorous bats because the bats usually improve seed germination after ingestion. Although seed germinability is known to vary greatly after ingestion by different bats, the relative contribution of each bat species to seed germination within plant communities is poorly understood. In this study, we first determined the fauna of frugivorous bats in a semideciduous seasonal forest remnant in southern Brazil and subsequently identified the plant species of the seeds passed through their guts. Second, the germination performance (i.e., germination percentage and speed) of the seeds of three pioneering plants (Piper aduncum, Piper hispidinervum and Solanum granuloso-leprosum) ingested by the most abundant bats was compared with that of the non-ingested seeds (seeds collected from fruits). Additionally, the effects on seed germination of different bat species were compared. During one year, five species of frugivorous bats were caught, and the seeds of eleven identifiable plant species (not counting those of undetermined species) were found in their faeces. We found that the germination performance of the seeds of Piper species was significantly enhanced after ingestion by bats...

Allelopathic potential and survey of natural seed bank under the canopy of Copaifera Langsdorffii Desf

Silva, Regildo Márcio Gonçalves da; Santos, Valter Henrique Marinho dos; Borges, Fabiano Marcelino; Melo, Fabiano de Fátima Queiroz; Silva, Luciana Pereira
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 641-653
POR
Relevância na Pesquisa
36.53%
The aim of this study was to evaluate the allelopathic effect of soil samples collected under the canopies of three specimens of Copaifera langsdorffii the germination of Lactuca sativa and survey the natural seed bank according to seasonality. To test the allelopathic effect was carried experiments of pre and post-emergence with seeds of L. sativa and to quantify the stock of seeds, soil samples were collected from three specimens at three distances from the stem (1, 2 and 3 m) and at three depths (0-5, 5-10 and 10-15cm) in the region of savanna in the dry and wet seasons. The samples tested in bioassay of pre-emergence no significant influence on germinability, mean germination time and mean germination speed, but showed a difference in the synchronism of germination, these data were independent of sampling station. In test for post-emergence was observed statistical difference in the parameters evaluate (length of primary roots and hypocotyls) in both seasons. To quantify the natural seed bank were macroscopic analysis of each soil sample with the help of stereoscopic microscope. The analysis of the natural seed bank showed a larger number of seeds in the 0-5cm and in distance of 2m for both seasons. The results suggest the presence of allelochemical substances in soil samples collected under the canopy of Copaifera langsdorffii.; O objetivo deste trabalho foi avaliar o efeito alelopático de amostras de solo coletadas sob a copa de três espécimes de Copaifera langsdorffii na germinação de Lactuca sativa e realizar o levantamento do banco natural de sementes de acordo com a sazonalidade. Para testar o efeito alelopático realizou-se experimentos de pré e pós-emergência com sementes de L. sativa e para quantificar o estoque de sementes...

Importance of seed bank for the management of invasive Acacia dealbata; A importância do banco de sementes no controlo de Acacia dealbata

Passos, Isabel Maria Melo Mendes
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
46.93%
The management of invasive plants is a hard task, which may be further hampered by the existence of extensive and long-lived seed banks. Acacia dealbata is an Australian tree considered one of the most aggressive invasive plant species in Portugal; the species is known to produce a persistent seed bank, but its extension and viability hasn’t been explored. In this work we aim to characterize the seed bank of A. dealbata, namely its extension, germinability and viability, in order to contribute to the management of the species, but also increase knowledge about its ecology. The extension of the seed bank was assessed by collecting soil samples in invaded stands and adjacent areas and counting the seeds. These were then germinated at 25ºC and some were exposed to an initial temperature of 60ºC, aiming to assess the effect of extreme soil temperature in dormancy breaking. Results showed that beneath canopy the seed bank averaged 4 608 seed/m2 (± 820), but maximum values can reach 62 747 seeds/m2. In areas adjacent to the invaded stands a mean value of 9 seeds/m2 (± 5) was found, with maximum values of 632 seeds/m2. Although only 8,6% of the seeds germinated without any stimulus, in total 89,7% of the seeds found showed to be viable after scarification...

Seed size influence on germination responses to light and temperature of seven pioneer tree species from the Central Amazon

Aud,Fabiana F.; Ferraz,Isolde D.K.
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
Relevância na Pesquisa
36.55%
In Amazon secondary forests are dominated by pioneer species that typically produce large amounts of small and dormant seeds that are able to form a persistent soil seed bank. Seed dormancy in this group of species is overcome by environmental conditions found in open areas, such as high irradiation or alternating temperatures. Nevertheless, a variety of germination responses to environmental factors is known among pioneers; some of them may germinate in diffuse light or in darkness condition at constant temperature. Seed mass can be considered as one of the factors that promotes this variety. Regarding species with very small seeds, it seems that the trigger for germination is light and for larger seeds temperature alternation may be a more important stimulus. In this study we established a relationship between seed mass and germination response to light and alternating temperature for a group of seven woody pioneer species from the Amazon forest. We found that an increase in seed mass was followed by a decrease in the need for light and an increase in the tolerance to alternating temperatures. Understanding germination strategies may contribute with the knowledge of species coexistence in high diverse environments and also may assist those involved in forest management and restoration.

Seed bank modelling of volunteer oil seed rape: from seeds fate in the soil to seedling emergence

Soltani,E.; Soltani,A.; Galeshi,S.; Ghaderi-Far,F.; Zeinali,E.
Fonte: Sociedade Brasileira da Ciência das Plantas Daninhas Publicador: Sociedade Brasileira da Ciência das Plantas Daninhas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 EN
Relevância na Pesquisa
36.57%
Studies were conducted to estimate parameters and relationships associated with sub-processes in soil seed banks of oilseed rape in Gorgan, Iran. After one month of burial, seed viability decreased to 39%, with a slope of 2.03% per day, and subsequently decreased with a lower slope of 0.01 until 365 days following burial in the soil. Germinability remained at its highest value in autumn and winter and decreased from spring to the last month of summer. Non-dormant seeds of volunteer oilseed rape did not germinate at temperatures lower than 3.8 ºC and a water potential of -1.4 MPa ºd. The hydrothermal values were 36.2 and 42.9 MPa ºd for sub- and supra-optimal temperatures, respectively. Quantification of seed emergence as influenced by burial depth was performed satisfactorily (R² = 0.98 and RMSE = 5.03). The parameters and relationships estimated here can be used for modelling soil seed bank dynamics or establishing a new model for the environment.

Tetrazolium test for evaluating triticale seed viability

Souza,Camila Ribeiro de; Ohlson,Osvaldo de Castro; Gavazza,Melícia Ingredi Araújo; Panobianco,Maristela
Fonte: Associação Brasileira de Tecnologia de Sementes Publicador: Associação Brasileira de Tecnologia de Sementes
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2010 EN
Relevância na Pesquisa
36.58%
Freshly harvested triticale seeds are usually dormant, making the immediate evaluation of the physiological potential of seed lots difficult. We evaluated different triphenyl tetrazolium chloride (TTC) test methods for rapidly determining the viability of four seed lots of x.Triticosecale Wittmack cultivar IPR111. The test variables were: Preconditioning, (i) placing whole seeds between moistened paper towels or (ii) directly soaking the seeds in water, both procedures being conducted at 20 ºC for 18 hours; Post-conditioning seed preparation, (i) longitudinal bisection of the seed through the embryo with one half being stained and the other discarded or (ii) longitudinal bisection with both halves being stained; Staining for three and four hours, in the dark, with 0.1%, 0.5% or 1.0% (w/v) TTC according to the preconditioning method described above, (i) both halves of each seed were placed on filter paper moistened with TTC and maintained at 40 ºC or (ii) one half of each seed was immersed in 5 mL of TTC solution in a 100 mL glass beaker at 30 ºC. The best results were obtained by preconditioning seeds between moistened paper towels at 20 ºC for 18 hours and staining on filter paper with 1.0% (w/v) TTC for three hours at 40 ºC.

Germinability after desiccation, storage and cryopreservation of seeds from endemic Encholirium Mart. ex Schult. & Schult. f. and Dyckia Schult. & Schult. f. species (Bromeliaceae)

Tarré,Erika; Pires,Bárbara Balzana Mendes; Guimarães,Ana Paula Mançano; Carneiro,Leonardo Alves; Forzza,Rafaela Campostrini; Mansur,Elisabeth
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2007 EN
Relevância na Pesquisa
37.03%
(Germinability after desiccation, storage and cryopreservation of seeds from endemic Encholirium Mart. ex Schult. & Schult. f. and Dyckia Schult. & Schult. f. species (Bromeliaceae)). Seed storage procedures require previous determination of optimal temperature and light conditions for germination, as well as of tolerance to desiccation and low temperatures. The aim of this paper was to study the effects of desiccation, storage at low temperatures and cryopreservation on the germinability of seeds of six Encholirium and two Dyckia species, which were selected according to vulnerability criteria. Initial germinability of newly harvested seeds varied from 35 to 95%. Seeds presented photoblastic behaviour since light was necessary to induce or increase germination. Except for E. heloisae and E. scrutor, desiccation did not affect significantly the germinability of tested seeds. Storage for one year at 4 and -20 ºC did not affect the germinability of desiccated seeds, except for E. pedicellatum. Germinability after freezing in liquid nitrogen was higher than or similar to control seeds for all species. However, freezing tolerance of E. pedicellatum seeds was only achieved after desiccation to 2.5% moisture content. As regards tolerance to desiccation and to storage at low temperatures...

Seed germination ecophysiology of the wild pineapple, Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae)

Silveira,Fernando Augusto Oliveira; Santos,Jean Carlos; Fernandes,Geraldo Wilson
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
Relevância na Pesquisa
36.55%
In this study we investigated the effects of light, temperature, and storage on seed germination of the wild pineapple Ananasananassoides, an understorey species found in cerrado woodlands. Seeds were germinated at temperatures of 15, 20, 25, 30 and 35 ºC and a 12-hr photoperiod and continuous darkness for 30-d. Seeds were photoblastic and the optimum temperatures for germination were 25 and 30 ºC. Seeds stored for 12-mo at room temperature and at 4 ºC were set to germinate at optimum conditions. Germinability of stored seeds did not differ from that of recently collected seeds, regardless of storage temperature, indicating their physiological potential for seed bank formation. Our results suggest that as in tropical rainforests, light may be an important factor controlling recruitment from seed banks for small-sized species from the cerrado woodlands.

The role of historical and ecological factors on initial survival of Copaifera langsdorffii Desf. (Fabaceae)

Fagundes,Marcílio; Costa,Fernanda Vieira da; Antunes,Suélen Ferreira; Maia,Maria Luiza Bicalho; Queiroz,Antônio César Medeiros de; Oliveira,Leonardo Queiroz; Faria,Maurício Lopes de
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 EN
Relevância na Pesquisa
37.04%
The plant population dynamic is affected by ecological and evolutionary processes that operate at all stages of the plant life cycle. The aim of this study was to characterize the seed and seedling performance of Copaifera langsdorffii by testing four hypotheses: the resource concentration hypothesis; the relationship between seed size and germinability hypothesis; the relationship between seed size and seedling vigor hypothesis; and the intraspecific seedling competition hypothesis. All seeds used in the experiments were collected from 35 C. langsdorffii plants located in a fragment of the Brazilian cerrado (savanna). The number of fruits per plant negatively affected Rhinochenus brevicollis attacks on C. langsdorffii seeds. Therefore, this result does not support the resource concentration hypothesis, and predator satiation was used in order to explain the observed result. In general, seed germinability (percentage and time to emergence) was not influenced by seed size. The homogeneity of the experimental design, together with an abundant water supply, may have masked the effects of seed size on germinability. Seed size positively affected seedling development, corroborating the expected relationship between seed size and seedling vigor. The number of seedling per plastic bags negatively affected the growth of C. langsdorffii. The nutrient-limited soil probably promoted the below-ground competition for nutrients among seedlings. Finally...

Psychotria hoffmansegiana (Willd ex Roem. & Schult.) Mull. Arg. and Palicourea marcagravii st. Hil. (Rubiaceae): potential for forming soil seed banks in a brazilian Cerrado

Araújo,CG.; Cardoso,VJM.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2007 EN
Relevância na Pesquisa
36.57%
The germinability of artificially buried Psychotria hoffmansegiana and Palicourea marcagravii seeds in Cerrado soil was tested, with the aim of evaluating whether dispersed seeds may be able to form a soil seed bank. The assays were carried out at a Cerrado Reserve in São Paulo State, Brazil. Seed samples were placed in nylon bags and buried at two different depths and in two different sites. Samples were periodically exhumed and germination tests were performed with both exhumed and dry stored seeds. In general, soil storage favoured seed survival and germination when compared to dry stored seeds. The seed germination was little affected by soil depth and by burial environment. Seeds of both species remained viable for at least 13 months, considering the time lapse between the collection and the end of the germination tests. It was suggested that both species can potentially form a persistent soil seed bank in Cerrado.

Ecologia de espécies poliembriônicas com ênfase no Bioma Cerrado; Ecology of polyembryonic species with emphasis in Cerrado Biome

Mendes-Rodrigues, Clesnan
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
36.57%
A ocorrência de mais de um embrião por semente, conhecida como poliembrionia, e a reprodução assexuada via semente, conhecida como apomixia, são processos comumente associados. Os registros e a importância destes eventos vêm aumentando nas últimas décadas, tanto entre as Angiospermas como um todo quanto em biomas como o Cerrado, reconhecido como um bioma onde a reprodução sexuada é predominante. Apesar destes registros, existem ainda poucas informações sobre a ecologia das sementes poliembriônicas. Nesse cenário, objetivou-se confirmar a poliembrionia como indicador de apomixia em espécies arbóreas e arbustivas de Cerrado e, a partir de estudos alocação de recursos entre embriões, de germinação de sementes, emergência e crescimento de plântulas, tentar definir quais são as vantagens e desvantagens da poliembrionia para a ecologia das espécies. De um total de 132 espécies amostradas, 30,30% apresentaram poliembrionia, embora somente 6,82% apresentem porcentagens de sementes poliembriônicas acima de 5% e sejam mais diretamente associadas a presença de apomixia. Entre as melastomatáceas, uma família característica dos Neotrópicos e muito bem representada no Cerrado, 33,96% das espécies apresentam poliembrionia...

Variabilidade gen??tica e a efici??ncia de sele????o no car??ter dorm??ncia de sementes em aveia-preta(Avena strigosa Schreb.); Genetic variability and breeding efficiency for seed dormancy in blac oat (Avena strigosa Schreb.)

MOLITERNO, Enrique Alfredo Parachu
Fonte: Universidade Federal de Pelotas; Agronomia; Programa de P??s-gradua????o em Ci??ncia e Tecnologia de Sementes; UFPel; BR Publicador: Universidade Federal de Pelotas; Agronomia; Programa de P??s-gradua????o em Ci??ncia e Tecnologia de Sementes; UFPel; BR
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
47.34%
Seed dormancy is a trait shown by a large variety of weedy plants, which helps the purpose of perpetuating the species through space and time by delaying germination until specific environmental cues happen. Black oat, a temperate forage grass, is widely used for pasture and as a cover crop in minimum tillage systems in Southern Brazil. However, the largest portion of the seed sown belongs to an old variety, which has no genetic identity, contributing to the appearance of undesirable agronomic traits in a crop species such as seed dormancy. This trait is hold responsible for turning black oat into a potential weedy species in areas sown to other cool season cereals, such as wheat and barley. Three methods were used to screen and select for black oat genotypes expressing low seed dormancy, i.e. screening of lines collected throughout different agricultural regions of the state of Rio Grande do Sul; subjecting a specific line of the species to the effects of two chemical and one physical mutagens and crossbreeding between selected lines and commercial cultivars of the species. All three methods were undertaken under a glasshouse environment (without temperature control), and since there are no known vegetative morphological traits associated to seed dormancy the procedure consisted on selecting seedlings from non dormant seeds. These were grown in the glasshouse environment and their progeny seeds tested for germinability...

Effect of water stress during seed development on morphometric characteristics and dormancy of wild radish (Raphanus raphanistrum L.) seeds

Eslami, S.; Gill, G.; McDonald, G.
Fonte: Gorgan University of Agricultural Sciences and Natural Resources Publicador: Gorgan University of Agricultural Sciences and Natural Resources
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
36.57%
The effects of water stress on morphometric characteristics of wild radish seeds as well as the expression of its seed dormancy were investigated in a pot trial at Roseworthy, South Australia in 2005. This experiment was carried out in a completely randomised design with five water regimes (control, S4, S5, S6 and S8) and four replicates. The water stress was exerted by withholding irrigation and placing the pots under a rain shelter at different growth stages starting with the onset of flowering (S4) and ending with the completion of flowering (S8). Wild radish pods from all the treatments were collected fortnightly from November 11 to December 23, 2005 (four collection dates). Seed dormancy was tested with and without pod for all treatments in January and May 2005. All morphometric characteristics of pods including pod wall weight and seed weight were negatively affected by water stress. Pods sampled earlier had thicker pod walls and greater pod segment weight. The germinability of all treatments increased with pod removal. The dormancy level tended to be lower in later collected pods. This Study showed that expression of seed dormancy was influenced by water stress during reproductive development. Therefore, variability in spring rainfall could have a major influence on the level of dormancy in seeds of this weed species produced in different growing seasons.; S.V. Eslami...

Tropical seed species' responses to liquid nitrogen exposure

Salomão,Antonieta Nassif
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2002 EN
Relevância na Pesquisa
37.02%
The ability to tolerate ultra-low temperature (-196 ºC) exposure was evaluated in 66 tropical orthodox seed species of 21 botanical families from the Cerrado (Brazilian Savannah) and Atlantic Forest Brazilian biomes. Liquid nitrogen had no effect on the germinability of 51 seed species. The stimulatory effect of cryogenic temperature on germinability, with or without subsequent chemical scarification, was observed in nine seed species with deep physical dormancy, or heterogeneous levels of seed hardness, or with no dormancy. Significant reduction in germinability occurred in six seed species, presumably because of factors acting individually or in combination on these seeds, such as inappropriate moisture content, or the potentially detrimental effect of rapid cooling (263 ºC.min-1) or fungal contamination. The results obtained suggest that cryopreservation may be a promising alternative for storing most of the seed species tested.

Weedy adaptation in Setaria spp.: IX. Effects of salinity, temperature, light and seed dormancy on Setaria faberi seed germination

Dekker, J.; Gilbert, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/08/2014
Relevância na Pesquisa
36.55%
Life in salty habitats is a function of tolerance to those chemicals at all critical phases of a plant's life history. The ability to withstand salt as an established plant may require different mechanisms and plant traits than those needed to germinate in salty soils. Seeds establishing themselves in high salt content may respond differently depending on the light conditions and seed germinability at the time of salty water imbibition. S. faberi seed (and S. viridis and S. pumila) plants were discovered thriving along the seacoasts of Southern Japan. These plants possess the ability to after-ripen, germinate, emerge and establish themselves, grow and reproduce in the salty soils and salt-laden atmospheres present in these windy habitats. The objectives of this paper are to determine the effect of salt (NaCl) in water imbibed by S. faberi seed during after-ripening and germination, as well temperature and light. Observations made also provide insights on the possible relationship between salt and drought tolerance. Seed germination of all phenotypes inhibited by two percent or more of NaCl. The effects of lesser amounts of NaCl on each of the three phenotypes was highly dependent on the specific temperature and light conditions. The three test phenotypes provided a good range to detect responses to salinity...

Ex situ seed conservation of Brazilian cacti

Nascimento, Joana P. B.; Vieira, Daniela C. M.; Meiado, Marcos V.
Fonte: Programa de Pós Graduação em Desenvolvimento e Meio Ambiente – PRODEMA Publicador: Programa de Pós Graduação em Desenvolvimento e Meio Ambiente – PRODEMA
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 13/06/2015 ENG
Relevância na Pesquisa
37.1%
Evaluation of the seed germination is an important aspect to the determination of seed longevity and, consequently, plant conservation. The aim of the present study was to analyze the effect of storage time on seed germination for eight species of Cactaceae. Seeds placed in cold storage (7 ± 2°C) in periods ranging from 24 to 30 months. The effect of storage time was analyzed through a comparison of stored seeds and recently collected seeds that have been evaluated before storage. Throughout the storage period, seeds from Pilosocereus pachycladus subsp. pachycladus and Pilosocereus tuberculatus maintained germinability similar to that of recently collected seeds. Germinability was reduced for seeds from Cereus albicaulis, Cereus jamacaru subsp. jamacaru and Pilosocereus pachycladus subsp. pernambucoensis, but the seed germination remained above 50%. Drastic reductions in germinability occurred after storage for seeds from Cereus pernambucensis subsp. fernambucensis, Pilosocereus chrysostele and Pilosocereus gounellei subsp. gounellei. No significant differences in the other germination variables were found for any of the species studied. Based on the present findings, the ex situ conservation of germplasm through a seed bank in cold storage is an effective method for the conservation of seeds...

Seed germination and seedling growth of two Pseudobombax species (Malvaceae) with contrasting habitats from Brazilian Cerrado

Mendes-Rodrigues,Clesnan; Oliveira,Paulo Eugênio; Ranal,Marli Aparecida
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
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Pseudobombax tomentosum and P. longiflorum are common trees in the Cerrado region, but the former species is more common in forest edges while the later is present in open cerrado areas. This work aimed to investigate differences in seed germination and seedling growth in these species, from seed collected from Cerrado areas in Central Brazil. For this, a seed germination experiment was designed and included four replicates with 25 seeds per species; seeds were randomly distributed in the germination chamber. To evaluate initial seedling growth, seedlings height was measured up to 67 days after seedling emergence; besides, some of these seedlings were grown for biomass evaluation during nine months. Results showed that seeds of the two species had the same germinability (near 100%) and mean germination time (ca. 12 days). However, P. longiflorum showed a more spread seed germination through time, with higher values of coefficient of variation in germination time and uncertainty index; and lower values of synchronization than P. tomentosum. The two species showed basically the same growth pattern, but lower values for height of apical meristem, diameter of underground structures (mostly roots), dry mass of shoots, underground structure and total mass of seedlings in P. tomentosum were obtained...