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Search Results: 1 - 10 of 73988 matches for " Barbedo Claudio José "
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Short storability of Caesalpinia echinata Lam. seeds as a consequence of oxidative processes
Lamarca, Edmir Vicente;Barbedo, Claudio José;
Hoehnea , 2012, DOI: 10.1590/S2236-89062012000400006
Abstract: the seed bank is one of the strategies for the preservation of endangered species, such as caesalpinia echinata lam. in this work we studied the changes in o2 consumption and co2 release by seeds incubated at different temperatures and water contents, evaluating the deterioration of seeds through germination and tetrazolium tests. our results demonstrated that the deterioration processes occurring in c. echinata seeds are related to respiration and possibly other oxidative processes, causing the death of embryonic tissues in short periods and loss of seed viability. this characteristic means that seed bank is an alternative for caesalpinia echinata conservation, however it depends on the control of these oxidative processes.
Potencial de inibi??o da regenera??o de raízes e plantulas em sementes germinantes de Eugenia pyriformis
Amador, Talita Silveira;Barbedo, Claudio José;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011000800005
Abstract: the objective of this work was to evaluate the potential for inhibiting the formation of new roots and seedlings from germinating seeds of "uvaieira" (eugenia pyriformis), fragmented and fissured. seeds were separated by size into two groups. each group was separated into two subgroups, one of which was subjected to germination test. seeds of each subgroup were subjected to two types of incision (total or partial) and, then, evaluated as for the production of roots and seedlings. seeds with partial incision, which had only one developed plantlet, had the incision completed until the halves were separated. the half fragment containing the root was discarded, and its complementary part was placed to germinate, in order to evaluate the production of roots and seedlings in these fractions without the roots. the design in all the experiments was completely randomized, in a 2x2 factorial arrangement (length x seed visible germination) or 2x4 (seed size x incision type). fragmented seeds of "uvaieira" shows potential for root and seedling regeneration and can produce more than one seedling per seed. germination starts inhibition processes of formation of new roots and plantlets, and the incision of cotyledons can block this inhibition.
Tolerancia à desseca??o de sementes de espécies de Eugenia
Delgado, Liliana Ferreira;Barbedo, Claudio José;
Pesquisa Agropecuária Brasileira , 2007, DOI: 10.1590/S0100-204X2007000200016
Abstract: the objective of this work was to evaluate the desiccation tolerance of seeds of six fruit species of eugenia (e. brasiliensis lam., e. cerasiflora miq., e. involucrata dc., e. pyriformis camb., e. umbelliflora berg. and e. uniflora l.) aiming to provide information for the conservation of the germinability of these seeds during storage. seeds were dried continuously in oven (40oc) or closed chambers with silica gel (25oc) until 10% water content. after drying, samples of the seeds were analyzed for water content and germination. as water content decreased, seeds lost viability, independently of the drying method. seeds from each species differed on sensitivity to desiccation, but all seeds were intolerant to levels lower than 45% water content and lost viability at levels lower than 15%.
Efeito da idade e do repouso pós-colheita de frutos de pepino na semente armazenada
Barbedo, Claudio José;Barbedo, Adeliana Saes Coelho;Nakagawa, Jo?o;Sato, Osvaldo;
Pesquisa Agropecuária Brasileira , 1999, DOI: 10.1590/S0100-204X1999000500015
Abstract: seeds from two cucumber (cucumis sativus l.) cultivars, pérola and rubi, were evaluated in relation to physiological quality to verify the effects of age and postharvest period of fruits on seed storage potential. fruits were harvested from 15 ('rubi') or 20 ('pérola') to 45 days after flowering and mantained in postharvest for 0, 5, 10, and 15 days before seeds extraction, at room conditions. seeds were dried and stored in paper bags at room conditions for two and three years. before and after the storage periods, samples were taken to germination and vigour tests. results showed that immature seeds (extracted from immature fruits - 30 days after flowering) without post-harvest period, did not germinate at second year. however, seeds with high germination at initial test, from either ripe fruits (40-45 days) or immature fruits (30-35 days) with 10 or 15 days of post-harvest, mantained high germination (more than 70%) after three years of storage.
Popula??o de plantas, método de colheita e qualidade de sementes de cenoura, cultivar Brasília
Pesquisa Agropecuária Brasileira , 2000, DOI: 10.1590/S0100-204X2000000800018
Abstract: brasília is a cultivar of carrot with a possibility of root production in hot areas and periods of high temperature. the seed production of this cultivar still requests research regarding to artificial induction of flowering and plant population. this work aimed at the study of these factors in the seed to seed method, brasília cultivar, in s?o manuel, sp, brazil. two experiments were carried out with and without spraying gibberellic acid. the plant densities were 25,000, 50,000, 100,000, 200,000, and 400,000 plants ha-1. the seeds were divided according to the origin of their harvest, forming two groups: umbels seeds from the first and second orders (selected harvest) and umbels seeds from the second and other orders (general harvest). after each harvest the seeds were evaluated taking into consideration the physical characteristics, germination, vigour, 1.000seed weight and water content. there were flowering and seed production in both experiments (with and without ga3 spraying). in general, seeds from selected harvest had superior quality than the ones from the general harvest with difference in germination up to about 16%. increase in plant population up to 200,000 plants ha-1 did not alter the seeds quality.
Popula o de plantas, método de colheita e qualidade de sementes de cenoura, cultivar Brasília
Pesquisa Agropecuária Brasileira , 2000,
Abstract: Brasília é uma cultivar de cenoura com possibilidade de produ o de raízes em áreas e épocas de elevada temperatura. A produ o de suas sementes ainda requer pesquisa quanto ao estímulo artificial ao florescimento e popula o de plantas. Objetivou-se, neste trabalho, o estudo desses fatores, no método semente-semente, da cultivar Brasília, em S o Manuel, SP. Foram conduzidos dois experimentos, com e sem aplica o de ácido giberélico. As popula es foram 25.000, 50.000, 100.000, 200.000 e 400.000 plantas ha-1. As sementes foram separadas de acordo com a origem de sua coleta, constituindo dois grupos: sementes de umbelas de primeira e segunda ordem (colheita selecionada) e sementes de todas as umbelas da parcela útil (colheita geral). Após cada colheita foram realizados análises de pureza física, testes de germina o e de vigor (emergência de plantulas em campo e envelhecimento acelerado), avalia es do peso de mil sementes e do teor de água. Houve florescimento e produ o de sementes, mesmo sem a aplica o do ácido giberélico. De modo geral, as sementes de colheita selecionada apresentaram qualidade superior às de colheita geral, com diferen as de germina o de até 16%. O aumento da popula o de plantas, até 200.000 plantas ha-1, n o diminuiu a qualidade das sementes.
Limites térmicos para a germina??o em fun??o da origem de sementes de espécies de Eugenia (Myrtaceae) nativas do Brasil
Lamarca, Edmir Vicente;Silva, Cristiana Vendrame e;Barbedo, Claudio José;
Acta Botanica Brasilica , 2011, DOI: 10.1590/S0102-33062011000200005
Abstract: seed germination is dependent on several abiotic factors including temperature. in this study, we analyzed the germination of seeds of eugenia brasiliensis, e. involucrata, e. pyriformis and e. uniflora in response to diff erent conditions of light and temperature. seeds of all species showed high germination values from 20 to 30 oc. germination of seeds of e. pyriformis was also evaluated at temperatures higher than 30 oc and lower than 20 oc. the germination and the normal seedling development occurred from 10 oc to 35 oc, not at 5 oc and 40o c. results also showed that desiccation changed the limits for germination in e. pyriformis since the most dehydrated seeds had the highest damaged in germination at suboptimal temperatures. thermal time during development and maturation of seeds was also considered. the seeds of e. pyriformis from lavras, mg, which received the greatest number of degree-days during development and maturation, showed better performance than the seeds from campinas, sp and s?o paulo, sp.
Mobiliza??o de água e conserva??o da viabilidade de embri?es de sementes recalcitrantes de ingá (Inga vera Willd. subsp. affinis (DC.) T. D. Pennington)
Andréo, Yara;Nakagawa, Jo?o;Barbedo, Claudio José;
Brazilian Journal of Botany , 2006, DOI: 10.1590/S0100-84042006000200012
Abstract: the water content of anhydrobiotic (orthodox) seeds is usually reduced to low values and its metabolism is reduced to a level that viability can be preserved for long periods. in contrast, typical non-anhydrobiotic (recalcitrant) seeds are intolerant to desiccation, possess lower longevity, and need a minimum water level to maintain viability, but the metabolism is still too active leading to a short seed longevity. in the present research "inga" seed embryos were stored in contact with polyethylene glycol 6000 (peg) solutions, at pre-defined water potential with the objective of improving storability and longevity. results indicated that germination of embryos kept in peg solution at -2.4 mpa was higher than 80% after 90 days of storage at 10 oc, while the germination of embryos kept at distilled water (0 mpa), at the same temperature, was lower than 60%.
Viabilidade e vigor de sementes de Caesalpinia echinata Lam. (pau-brasil - Leguminosae) pelo teste de tetrazólio
Lamarca, Edmir Vicente;Leduc, Simone Nadur Mota;Barbedo, Claudio José;
Brazilian Journal of Botany , 2009, DOI: 10.1590/S0100-84042009000400017
Abstract: as an important method to quickly evaluate seed vigor and deterioration, both of them related to seed physiological quality, the tetrazolium test was analyzed for seeds of caesalpinia echinata lam. (brazilwood). mature seeds were incubated in 0.05% to 1.00% tetrazolium solutions for a period varying from 1 to 24 hours, at 35 °c without light. then, embryos of different levels of deterioration were analyzed under the best conditions (0.05%-0.075% for 2 hours) of incubation. it was possible to identify eight levels of vigor which will be important to a brazilwood seed lot diagnosis in a short time (4 hours) and to identify different types of embryo damages, the later essential to estimate seed storability.
Drying and storage of Eugenia involucrata DC. seeds
Maluf, Angela Maria;Bilia, Denise Augusta Camargo;Barbedo, Claudio José;
Scientia Agricola , 2003, DOI: 10.1590/S0103-90162003000300009
Abstract: the physiological quality of seeds of native species is important to produce healthy saplings and therefore guarantee the success of programs to recover disturbed vegetation. this reinforces the necessity for investigating the physiological quality of those seeds. to evaluate the effects of different drying rates on the germination, moisture content and storability of eugenia involucrata diaspores, mature fruits collected at mogi gua?u, sp, brazil had their epi- and mesocarps removed by washing and were dried at 30, 40 or 50oc until their water content was reduced from 57% (fresh diaspores) to 13% (final drying), totaling six drying levels. in a second experiment, diaspores had their moisture content reduced from 57% to 49%, at 30oc, totaling six drying levels (0h, 1h, 2h, 3h, 4h and 5h), and were kept for 180 days in plastic bags under cold storage. the drying rate had no effect on tolerance to desiccation by e. involucrata diaspores; water contents lower than 51% decreased both germinability and storability. diaspores can be stored for up to 180 days as long as their water content is reduced to 53% and they are kept inside plastic bags under cold storage.
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