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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Germination and emergence salt tolerance of sorghum (Sorghum bicolor L.) as influenced by seed quality and generations.

Alemayehu, Makonnen. January 1989 (has links)
Artificially aged and non-aged seeds of 22 grain sorghum (Sorghum bicolor L.) F₁ hybrids and their F₂ and F₃ generations were evaluated for germination salt tolerance. Six of the hybrids, along with their F₂ and F₃ generations, were tested for emergence salt tolerance. Effects of seed production environments on germination salt tolerance were also studied using F₂ generations of 12 sorghum hybrids produced under full-season irrigation, limited irrigation, and double-cropping conditions. Germination tests were conducted in a growth chamber, on trays, while the emergence test was conducted in a greenhouse in flats filled with sand. The experiments were conducted under non-saline and saline conditions in randomized complete block designs. Artificial seed aging resulted in significant reductions in germination percentages under both non-saline and saline environments. The overall mean reduction in germination caused by seed aging was more than twice as much under salinity stress as under the non-stress conditions (48 vs. 17%), indicating differential effects of salinity on different quality seeds. Entries that appeared to be resistant to seed aging also had higher germination percentages under salinity stress. Seed production environment influenced germination performance in both non-saline and saline environments. The overall mean germination percentages of sorghum seeds produced under three different field environments were significantly different from one another. Significant differences were observed in germination and emergence percentages within F₁, F₂, and F₃ generations. Except for the F₁ entries, however, emergence index differences within the F₂ and F₃ generations were not significant. Correlations between germination and emergence percentages in the non-saline and saline treatments were generally nonsignificant. This suggests that germination and emergence responses of sorghum may vary under different salinity levels and different environments.
262

Tissue specific expression of ABA and GA metabolic genes during grain development and with respect to dormancy and germination in barley

Park, Seokhoon 14 September 2015 (has links)
Seed development, germination and dormancy, considered as the most important phenomena in seeds, are regulated by several plant hormones; gibberellin (GA) and abscisic acid (ABA) being the major players acting antagonistically. The regulation of these seed related processes by GA and ABA is dependent partly on the endogenous levels of the two hormones, which in turn are determined by the balance between their biosynthesis and catabolism. This thesis investigated the spatial and temporal expression patterns of several members of the GA and ABA biosynthetic and catabolic gene families during grain development using a non-dormant cultivar and during imbibition using grains collected from dormant and non-dormant cultivars of barley. In addition, the thesis examined the effect of exogenous ABA treatment, and after-ripening of seeds collected from dormant cultivars on the expression patterns GA and ABA metabolism genes during grain development and imbibition, respectively. The results suggest that specific members of the gene families related to the metabolic pathways of the two hormones exhibit distinct spatial and temporal roles in the regulation of barley grain development, dormancy and germination. / October 2015
263

Estresse hídrico e osmocondicionamento de sementes de espécies e híbridos de eucalipto /

Justus, Rafael Aranha Pereira. January 2014 (has links)
Orientador: Rinaldo Cesar de Paula / Banca: Sérgio Valiengo Valeri / Banca: Bruno Ettore Pavan / Resumo: O presente trabalho objetivou avaliar o efeito do estresse hídrico sobre a germinação de sementes de seis espécies (Eucalyptus brassiana, E. camaldulensis, E. grandis, E. pellita, E. resinifera e E. urophylla) e quatro híbridos (E. brassiana x E. pellita, E. brassiana x E. tereticornis, E. grandis x E. camaldulensis e E. grandis x E. urophylla) de eucalipto, submetendo-os a seis potenciais hídricos (0, -0,2, -0,4, -0,6, -0,8 e -1,0 MPa) simulados por soluções aquosas de polietilenoglicol 6000 (PEG 6000). Pretendeu-se também avaliar o efeito do condicionamento osmótico de sementes sobre a porcentagem, velocidade de emergência em viveiro, sobre o desenvolvimento de mudas e sobre a possível indução de maior tolerância dessas mudas ao déficit hídrico, em casa de vegetação. Os experimentos realizados no laboratório e em viveiro foram conduzidos em delineamento experimental inteiramente ao acaso, e o realizado na casa de vegetação foi conduzido em blocos ao acaso. Os dados foram submetidos a análise de variância com comparação de médias pelo teste de Tukey e análise de regressão. Observou-se que o aumento da restrição hídrica afeta de forma diferenciada a germinação das espécies e híbridos de eucalipto, sendo E. brassiana x E. tereticornis, E. grandis x E. camaldulensis e E. resinífera os mais tolerantes à deficiência hídrica. O osmocondicionamento proporcionou o aumento na velocidade de emergência de E. brassiana x E pellita e E. brassiana x E. tereticornis, mas prejudicou a emergência de E. grandis x E. camaldulensis e de E. urophylla x E. grandis. Na etapa realizada na casa de vegetação o osmocondicionamento resultou na diminuição da média da altura das mudas de E. resinifera, E. grandis e E. grandis x E. camaldulensis, e no aumento da média desse caráter em E. brassiana x E pellita. Não houve diferença no período de sobrevivência das mudas provenientes de sementes osmocondicionadas e ... / Abstract: This research aimed valuate the effect of the water stress under the seed germination of six eucalypt species (Eucalyptus brassiana, E. camaldulensis, E. grandis, E. pellita, E. resinifera and E. urophylla) and four eucalypt hybrids (E. brassiana x E. pellita, E. brassiana x E. tereticornis, E. grandis x E. camaldulensis e E. grandis x E. urophylla), subjecting to six osmotic potentials (0, -0,2, -0,4, -0,6, -0,8 e -1,0 MPa) simulated by solutions of polyethylene glycol 6000 (PEG 6000) The aim was also to evaluate the effect of seed priming on percentage and emergence in nursery, on seedling development and the possible induction of drought tolerance to these seedlings, in greenhouse The experiments were carried out in completely randomized design, in laboratory and in nursery, and in completely randomized block in greenhouse. The data were subjected to analysis of variance and means compared by the Tukey test and regression analyses It was noted that the rising of water restriction affects in a different way the germination of the species and hybrids of eucalyptus, E. brassiana x E. tereticornis, E. grandis x E. camaldulensis and E. resinífera the most tolerant to the water deficit. The effect of the priming was little among the species and hybrids studied, giving a increasing in the emergency speed of the E. brassiana x E pellita e E. brassiana x E. tereticornis, but damaging the emergency rate of E. grandis x E. camaldulensis and de E. urophylla x E. grandis. In stage conducted in a greenhouse priming resulted in decreased of average seedling height on genotypes E. resinifera, E. grandis and E. grandis x E. camaldulensis, and increasing this characteristic of E. brassiana x E. pellita. No significant differences were found in survival time between the seedlings from primed seeds and the unprimed / Mestre
264

Germination and growth responses of Hordeum Vulgare SV13 cultivated as a green fodder crop for African conditions

Smith, Ryan Anthony January 2018 (has links)
Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2018. / This study evaluated the effects of 5 different soaking treatments in conjunction with 5 varying irrigation intervals on the germination, growth and nutritional values of seed of Hordeum vulgare Sv13. The 5 different soaking times consisted of 1, 3, 8, 16 and 24 hours. The barley seed was first cleaned and then placed in a vessel containing 500 ml of distilled water with a 20 % solution of sodium hypochlorite (bleach) at room temperature. Thereafter the pre-soaked seeds were transferred to a perforated container, containing no medium and placed into a growing chamber equipped with drip irrigation. The seed was then irrigated with 1245 ml of water at 5 different intervals namely every 2, 4, 8 10 and 12 hours. The temperature of the hydroponic growing room was kept at a constant 23 °C using a hotoperiod of 16-hour day/ 8-hour darkness. The seed was allowed to germinate and grow for a period of 8 days before being harvested. The objectives of this study were to determine the most beneficial combination of soaking treatment in conjunction with the most beneficial irrigation interval on the germination rate of the seed allowing for radicle emergence and coleoptile production. It was also used to determine which combination of treatments was most beneficial to the growth and nutritional values of the seed post-harvest. Another objective was to ascertain the shortest soaking time for application in a small-scale, hydroponic growing unit as well as the frequency of irrigation required to grow seedlings, thereby determining the amount of water required to produce a seedling mat for a small-scale, subsistence farmer, with the emphasis being on water reduction. Each treatment was replicated 10 times and consisted of 500 grams of seed, which when placed into its container measured 2 centimetres in depth, totalling 25 treatments in all. Germination was measured by observing radicle emergence in the first 2 days of the growing period first after a 24-hour cycle and again after 48 hours. The numbers of leaves present at harvest after an 8-day growing period were also counted to determine germination rate of the seeds. Growth was determined by average leaf height as well as the tallest leaf on day 8 of the growing cycle. Root mat expansion was also measured, post-harvest, which was compared to the initial 2 cm planting depth of seed. Wet and dry weights of the plant material were measured post-harvest. Samples of the harvested material were also sent for nitrogen and protein analysis. It was discovered that most of the results favoured a shorter soaking time and an increase in irrigation frequency, bar a few exceptions. Most favoured a pre-soaking time of only 1 hour together with an irrigation frequency of between 2 and 4 hours. This shows that small-scale farmers would be able to reduce the time spent on soaking of their seed. Although the frequency of the irrigation interval remained high further testing would be required to determine if the amount of water applied at each irrigation interval could be reduced and still produce favourable results. It would also remain to be seen if no irrigation during the 8-hour dark photoperiod would have any negative impact on germination, growth and nutritional values of the seedlings.
265

Avaliação do potencial fisiológico de sementes de cebola e sua relação com o desempenho das plantas em campo. / Physiological potential evaluation of onion seeds and its relation to field plant performance.

Rodo, Angelica Brod 06 March 2002 (has links)
O potencial fisiológico de sementes, determinado pela germinação e vigor, é diretamente responsável pelo desempenho das sementes em campo, podendo até se refletir na produtividade de diversas espécies de hortaliças de importância econômica. Diante disto, o presente trabalho teve como objetivo avaliar a eficiência de diferentes métodos para determinação do potencial fisiológico de sementes de cebola (Allium cepa L.), visando destacar procedimentos adequados para utilização em programas de controle de qualidade; procurou-se, também, verificar a relação dos resultados obtidos em laboratório com a emergência das plântulas e o desempenho das plantas em campo. Para tanto, utilizaram-se seis lotes de sementes dos cultivares Aurora e Petroline, avaliados, em laboratório, quanto ao grau de umidade, germinação e vigor (primeira contagem de germinação, classificação do vigor de plântulas, condutividade elétrica, frio sem terra, envelhecimento acelerado tradicional e com solução salina e deterioração controlada). O desempenho das plantas foi verificado em ensaios de campo, utilizando-se dois sistemas de cultivo: semeadura direta e transplante de mudas; durante o desenvolvimento das plantas avaliaram-se, periodicamente, a altura, o diâmetro na região do colo e a massa de matéria seca das plantas. Após a colheita, determinou-se o rendimento final e efetuou-se a avaliação comercial dos bulbos. Concluiu-se que os testes de envelhecimento acelerado com solução salina (41ºC/72h), de deterioração controlada (ajuste do grau de umidade das sementes para 24% de água/45ºC/24h) e de classificação do vigor de plântulas, são considerados eficientes para avaliação do potencial fisiológico de sementes de cebola. As relações entre o vigor de sementes de cebola e o desempenho das plantas manifestam-se apenas durante a fase inicial do desenvolvimento da cultura, principalmente quando as diferenças entre o potencial fisiológico dos lotes são mais acentuadas, mas não afetam diretamente a produção de bulbos. / Research has emphasized the relationship of laboratory germination and vigor to seedling emergence and stand establishment. In contrast, information relating seed vigor to plant performance is less available. This study was conducted to identify reliable procedures to rank onion ( Allium cepa L.) seed lots according to their physiological potential and to select the most adequate procedures to be used in quality control programs. In addition, it was verified whether the differences in seed vigor influence plant performance in field conditions. Six seed lots of cultivars Aurora and Petroline were evaluated in laboratory for germination and vigor (first count, seedling vigor classification, electrical conductivity, cold test, traditional and saturated salt accelerated aging and controlled deterioration). Field experiments to detect differences in plant development were performed by direct sowing and transplant systems; after the determination of seedling emergence, plant vegetative development was evaluated by plant height, pseudo stem width and dry matter accumulation measurements. After harvest, the bulbs commercial classification and yield evaluation were provided. It was concluded that saturated salt accelerated aging (41ºC/72h), controlled deterioration (24% of water/45ºC/24h) and seedling vigor classification tests were the best procedures to assess the physiological potential of onion seeds. The initial plant development as measured by plant height and dry matter accumulation was affected by seed vigor mainly when the differences of seed physiological potential became wider as a result of the storage period. Influence of seed vigor did not persist during plant vegetative growth and yield was not related to seed vigor level. It was therefore concluded that the use of high vigor seed lots is justified to ensure adequate stand establishment under different environmental conditions.
266

Extratos de Ascophyllum nodosum no tratamento de sementes de milho e soja: avaliações fisiológicas e moleculares / Ascophyllum nodosum extracts on seed treatment of maize and soybean: physiological and molecular assessments

Araujo, Diego Kitahara 08 April 2016 (has links)
A obtenção de uma lavoura com população adequada de plantas depende da utilização de diferentes práticas agronômicas, estando o sucesso condicionado ao uso de sementes de boa qualidade. No entanto, a semeadura dificilmente é realizada em condições ideais o que resulta em problemas na emergência das plantas. Grande é a procura por alternativas que melhorem a germinação e o desenvolvimento inicial dos cultivos resultando em uniformidade de emergência, garantindo o estande e culminando em produção. O tratamento de sementes com agroquímicos fitossanitários é uma solução parcial no combate de agentes fitopatológicos e pragas, mas poucas são as soluções adotadas para melhorar o desenvolvimento vegetal inicial, que pode levar a desuniformidade e falhas no estande gerando prejuízos econômicos. Os extratos de algas já demonstraram em diversos estudos sua eficiência no desenvolvimento vegetal quando aplicados em plantas. Porém poucos são os estudos voltados para os efeitos dos extratos de algas na germinação e emergência. Assim, o intuito deste trabalho foi testar o extrato comercial de Ascophyllum nodosum, e diferentes fracionamentos do mesmo, no tratamento de sementes de soja e milho. Avaliou-se o efeito de diferentes doses no desenvolvimento das plântulas e as doses de melhor resposta foram utilizadas no tratamento de sementes de soja a fim de associar as respostas obtidas à expressão gênica de 9 genes relacionados ao processo germinativo em 24 e 48h de embebição. Sementes de soja tratadas com o extrato comercial resultaram em plântulas menos desenvolvidas o que pode estar relacionado ao alto teor de sais contidos no produto. O tratamento com as demais frações favoreceu o desenvolvimento das plântulas, principalmente o desenvolvimento radicular. Sementes de milho tratadas não apresentaram desenvolvimento tão satisfatório quanto as sementes de soja tratadas. A análise da expressão gênica relativa demonstrou que o tratamento com frações do extrato comercial é capaz de regular algumas vias do metabolismo hormonal, como a isopentenil transferase e a GA20 oxidase 2, e do catabolismo de reservas, como a acil-CoA oxidase. Em condições ótimas, o tratamento de sementes de soja com frações do extrato comercial de A. nodosum favoreceu o desenvolvimento inicial das plântulas de soja, no entanto não ocasionou grandes alterações no desenvolvimento de milho. Este estudo demonstrou a possibilidade de utilização de frações do extrato de A. nodosum no favorecimento do desenvolvimento inicial de plântulas de soja. Maiores estudos são necessários quanto às respostas em campo e na atenuação de estresses para viabilizar seu uso como um bioestimulante em sementes. / To make a production field to achieve the suitable stand of plants someone depends on proper agronomic managements being the use of seeds of high quality one of the aspects to be taken into account. However, the sowing is rarely done under ideal conditions for the seeds germination, which leads to a considerable lack of uniformity of the stand. Researchers and farmers look for alternatives to improve the seeds germination as well as emergence and initial development of plants to achieve better stand uniformity, culminating in higher productivity. The seed treatment with fungicides and pesticides is a partial solution that control diseases and pests related to the seeds. However, very little attention is given to solutions to improve the initial development of plants that can result in poor stand and consequently lower economic yields. The A. nodosum extracts have shown through several studies their effectiveness in improving the plant development. However, those studies are not directed to the seeds germination and emergence of seedlings. Thus, this study was done to assess the A. nodosum extracts in different fractions on maize and soybean seeds treatment. Firstly, it was assessed the effect of different doses of A. nodosum extracts on the development of seedlings. The doses that showed better results were used for the soybean seed treatment aiming to associate the responses obtained to the expression of nine genes related to the germination process, at 24 and 48 hours of water uptake. Soybean seeds treated with the commercial extract of A. nodosum originated less developed seedlings. This effect can be due to the high content of salts present in the product. Treatments with the fractions of the product led to a better development of seedlings, mainly the radicular development. Maize seeds did not have the same performance as the soybean seeds. The relative gene expression analysis demonstrated that the treatment with fractions of commercial extract of A. nodosum is able to regulate some pathways of hormonal metabolism through enzymes as isopentenyl transferase and GA20 oxidase 2, and the storage catabolism, as acyl-CoA oxidase. Under ideal conditions, seed treatment with fractions of commercial extract of A. nodosum has improved the initial development of soybean seedlings, however, none or small changes were observed for the development of maize seedlings. This study shows the possibility of use of A. nodosum extract to favor the initial development of soybean crop. Additional studies are required to assess effects on fields and stresses attenuation to enable the use of the seaweed extract as a seed biostimulant.
267

Modelos não lineares e lineares generalizados para avaliação da germinação de sementes de milho e soja /

Amorim, Deoclecio Jardim, 1992. January 2019 (has links)
Orientador: Maria Márcia Pereira Sartori / Banca: Edivaldo Aparecido Amaral da Silva / Banca: Renato Fernandes Cantão / Banca: João Nakagawa / Resumo: Dentre as características mais estudadas na indústria de sementes e bancos de germoplasma, destaca-se o potencial fisiológico, tendo em vista que sementes de maior qualidade fisiológica permitem obter uma rápida e uniforme emergência das plântulas, e consequentemente o estabelecimento do estande. O objetivo dessa pesquisa foi avaliar a germinação de sementes de milho (Zea mays L.) e soja (Glycine max (L.) Merrill) por meio de modelos não lineares e lineares generalizados. Foram utilizadas as cultivares de milho: AS 1633 PRO3, 2B587 RR, 2A401PW, AL Bandeirante e BRS 4103, e de soja as cultivares: DS59716 IPRO, CD2737 RR, CD251 RR, CD2820 IPRO e CD2857 RR, ambas da safra 2016/17. Avaliou-se a germinação de 20 sementes com quatro repetições por cultivar por meio do teste de emissão da raiz primária (protrusão). A contagem das sementes germinadas foi efetuada em intervalos regulares de 6, 12 e 24 horas até 204 horas, adotando-se como critério de germinação a protrusão da raiz primária ≥ 2 mm. Os dados foram dispostos na forma de porcentagem acumulada ao longo do tempo e pela proporção de sementes viáveis em cada intervalo de tempo testado dado por uma sequência de ensaios de Bernoulli. Os dados de porcentagem acumulada ao longo do tempo foram modelados pelas curvas não lineares de Gompertz e função de Hill de quatro parâmetros e os dados de proporção foram avaliados por modelos lineares generalizados testando as funções ligação: Probit, Logit e Complemento Log Log. As cultivares ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Among the most studied characteristics in the seed industry and germplasm banks, the physiological potential stands out, since seeds of higher physiological quality allow a quick and uniform emergence of the seedlings, and consequently the establishment of the stand. The objective of this research was to evaluate the germination of corn (Zea mays L.) and soybean (Glycine max (L.) Merrill) seeds using nonlinear models and generalized linear. The used cultivars of corn were: AS 1633 PRO3, 2B587 RR, 2A401PW, AL Bandeirante and BRS 4103, and the soybean cultivars were: DS59716 IPRO, CD2737 RR, CD251 RR, CD2820 IPRO and CD2857 RR, both of the 2016/17 crop. The germination of 20 seeds with four replicates per cultivar was evaluated by the primary root emission test (protrusion). The germinated seeds were counted at regular intervals of 6, 12 and 24 hours up to 204 hours, with protrusion of the primary root ≥ 2 mm being the germination criterion. The data were plotted as a percentage accumulated over time and by the proportion of viable seeds at each interval of time tested given by a sequence of Bernoulli assays. The data of percentage accumulated over time were modeled by the non-linear Gompertz curves and Hill function with four parameters and the proportion data were evaluated by generalized linear models testing the linking functions: Probit, Logit and Complement Log Log.The corn cultivars with the highest germination speed were: AL Bandeirante and BRS 4103. For soybean the bes... (Complete abstract click electronic access below) / Mestre
268

Estágios de colheita e repouso pós-colheita dos frutos na qualidade de sementes de mamoneira

Silva, Líbia Belisário da [UNESP] 21 November 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-21Bitstream added on 2014-06-13T20:48:34Z : No. of bitstreams: 1 silva_lb_me_botfca.pdf: 393551 bytes, checksum: 68ad65b5247076fa26c16688a2d0cd1d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O presente trabalho teve como objetivo avaliar o efeito dos estágios de colheita e do repouso pós-colheita dos frutos na qualidade de sementes de mamoneira (Ricinus communis L.) cultivar AL Guarany 2002. Foram avaliadas 9 épocas de colheita dos racemos, dos 30 até 142 dias após a antese (DAA), em intervalos de 14 dias e quatro condições de repouso: sem e com repouso de sete dias de sementes extraídas (nuas), de frutos e de frutos presos ao racemo. Foram avaliados a massa fresca dos frutos, as dimensões e a cor de frutos e sementes; o teor de água, matéria seca, germinação e vigor das sementes (primeira contagem de germinação, porcentagem de plântulas vigorosas, emergência de plântulas em areia, índice de velocidade de emergência e condutividade elétrica). O estágio de colheita e o repouso póscolheita afetaram a qualidade das sementes de mamoneira. Sementes com máxima qualidade fisiológica e matéria seca foram obtidas de frutos colhidos aos 86 DAA. A colheita pode ser realizada até os 128 DAA sem redução da germinação, mas com prejuízos devido à queda dos frutos, dispersão das sementes aos 100 DAA e reduções do vigor. O repouso das sementes nuas permitiu a antecipação da colheita para 72 DAA sem prejuízos à germinação e matéria seca, mas com reduções de vigor. A cor dos frutos, das sementes e o teor de água das sementes foram parâmetros eficientes para a identificação do ponto de colheita, principalmente se usados conjuntamente. / This study aims to assess the effect of the harvesting stages process and the resting period of the post-harvest of fruits in the quality of castor bean seeds (Ricinus communis L.) AL Guarany 2002. It were assessed nine times in racemes, from 30 to the 142 day after anthesis (DAA), at intervals of fourteen days and four conditions of resting period; without and with resting period of seven days of seeds extracted (bare), fruits and fruits prisioners to the raceme. The fruits weight, the dimension and the fruits colour and seeds were then assessed: the content of water, dry matter, seed germination and vigour (first of germination, percentage of vigorous seedlings, emergence of seedlings in sand, speed emergence index and electric conductivity). The harvest stage and the post-harvest resting period affected the quality of castor bean seeds. Seeds with maximum physiological quality and dry matter were obtained from fruit harvested at 86 DAA. The harvest can be achieved by the 128 DAA without reducing germination, but with losses due to falling fruit, seed dispersal to 100 DAA and reductions in strength. The rest seeds bare allows the harvest to be brought forward to the 72 DAA without detriment to the germination and dry matter, but with reductions in strength. The colour of the fruits, seeds, and water content of seeds were effective parameters for the identification of the harvest point harvest, particularly if used together.
269

Subcellular localization of plant vacuolar sorting receptor proteins and their roles in mediating protein degradation during seed germination. / CUHK electronic theses & dissertations collection / Digital dissertation consortium

January 2003 (has links)
by Yubing Li. / "September 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 173-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
270

Ecologia da germinação de sementes e desenvolvimento de plantas de Platymiscium floribundum Vog. (Sacambu) - Fabaceae em viveiro e sob dossel de floresta ombrófila densa, São Paulo, SP

Figliolia, Marcia Balistiero [UNESP] 02 December 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-02Bitstream added on 2014-06-13T19:01:07Z : No. of bitstreams: 1 figliolia_mb_dr_rcla.pdf: 2811984 bytes, checksum: b1692752dd1e7065b3f766c9d1ca22a9 (MD5) / O objetivo geral da pesquisa foi estudar aspectos da germinação de sementes de Platymiscium floribundum Vog. em laboratório e viveiro e desenvolvimento das mudas em condições de viveiro e natural sob o dossel, com vistas a estabelecer indicadores biológicos quanto à fisiologia e ecologia da germinação e desenvolvimento das plantas para subsidiar projetos de conservação, de manejo e de revegetação de áreas alteradas ou desprotegidas. Tendo como enfoque o estudo das temperaturas cardeais de germinação das sementes e o estabelecimento de padrões tecnológicos de análise foram testadas, em condições controladas de laboratório, temperaturas no intervalo de 10 a 40ºC, com presença contínua e ausência total de luz branca. Verificou-se que a faixa limite de germinação está entre 10 e 12,5 e 37,5 e 40ºC; a 10ºC iniciou-se somente a protrusão radicular, sem emissão da raiz primária e, a 40ºC, houve morte total das sementes. A faixa ótima de temperatura para a germinação, na presença contínua de luz, está entre 15 a 25ºC, com maiores índices de velocidades de germinação a 20 e 25ºC. Para o estudo ecofisiológico foram testadas as interações entre diferentes regimes de temperatura, quantidades de água e luz. As temperaturas onde a germinação das sementes se mostrou superior foram 25, 20 e 15ºC. Os resultados de germinação com as quantidades de água do ii substrato de 30 e 60mL foram superiores à de 90mL. Os percentuais de germinação foram inferiores à medida que se associaram elevadas quantidades de água e temperatura. As sementes da espécie apresentaram insensibilidade à luz, germinando tanto na presença quanto na ausência de luz, não apresentando variação significativa entre os espectros de luz testados. Os resultados indicam que P. floribundum apresenta plasticidade... / The purpose of the present work was the study of germination under laboratory and nursery conditions and seedling development under nursery and field conditions for getting biological indicators of ecophysiology of germination and establishment of Platymiscium floribundum Vog for conservation, management and reforestation projects. Determination of cardinal, and optimum temperatures was done by isothermic incubations in the range of 10 to 40°C, under continuous white light and darkness. The minimum temperature was 12.5°C and the maximum 37.5°C. At 10°C, only radicle protrusion was observed and at 40°C the seeds have died. The optimum temperature range from 15 to 25°C with highest germination rate at 20 to 25°C. For ecophysiological study, different temperatures were tested under different conditions of substrate humidity and light. The germination under low humidity (30mL) and moderate humidity (60mL) of the substrate was higher than high humidity (90mL). Seeds of P. floribundum were light insensitive. The seedling emergence capacity under nursery conditions were high under both natural light (NL) and far red light (FR) in all tested shading percentage (10, 18, 30, 50 and 80 shading), with high seedling survival under 30 and 80% shading NL and 18, 30 and 50% shading FR. Seedling development was high under FR at 18, 30 and 50% and in stem diameter at all WL treatments. Plants accumulated more root and aerial dry matter under NL. By aerial to root dry matter ratio, highest aerial development was observed under 0, 30, 18 and 80% shading WL and 18 and 80% shading FR. Analysis of seedling development was carried out under natural conditions under two shading intensities under canopy at Serra da Cantareira, São Paulo... (Complete abstract, click electronic address below)

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