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dos Santos F.,Instituto Agronomico Of Campinas | Medina P.F.,Laboratorio Of Analise Of Sementes | Parisi J.J.D.,Instituto Agronomico Of Campinas
Revista Brasileira de Sementes | Year: 2011

The use of vigor tests for assessing seed lot quality is an important tool for production and commercialization. However, research on evaluating the quality of lettuce and endive seeds is still scarce since only the germination test is considered as standardized for lettuce seeds and other tests must be improved to obtain more accurate information. In order to adapt the methodology of the accelerating aging tests to evaluate the quality of lettuce and endive seed lots, four seeds lots of 'Maravilha' and 'Verdinha' lettuce cultivars and four seeds lots of 'Catalonha' and 'Pão-de-Açúcar' endive cultivars were used. In the accelerated aging test, the seeds were submitted to the traditional aging method and to aging with a saturated and diluted NaCl solution for 48, 72 and 96 hours. To characterize seed lot quality, the seed moisture content was determined and the germination test, first germination count and seedling emergence in the greenhouse were verified. It was concluded that the accelerated aging test allows the separation of seeds lots into different vigor levels. The 48-hour aging period can be used with the traditional method and the 72-hour period for the saturated NaCl solution for both lettuce and endive seeds. Considering the method using a diluted NaCl solution, the best periods were 48 hours for lettuce seeds and 72 hours for endive seeds.

Andreo-Souza Y.,Laboratorio Of Analise Of Sementes | Pereira A.L.,Laboratorio Of Analise Of Sementes | da Silva F.F.S.,Laboratorio Of Analise Of Sementes | Riebeiro-Reis R.C.,State University of Feira de Santana | And 3 more authors.
Revista Brasileira de Sementes | Year: 2010

The physic nut (jatropha curcas l.) Shrub is found in almost all the intertropical regions, and is adaptable to climatic conditions from the brazilian northeast to são paulo and paraná. We evaluated the effects of salt stress on j. Curcas seeds and seedlings grown under laboratory and field conditions. In the laboratory experiments, two lots of physic nut seeds were submitted to different concentrations of sodium chloride dissolved in distilled water to produce electrical conductivities (ds m-1) of 2, 4, 6, 8, 10 and 12. For the field experiments, plants were grown in pots watered with sodium chloride dissolved in distilled water to produce electrical conductivities of 2 ds m-1, 4 ds m-1 and 6 ds m-1. A distilled water control was used for both sets of experiments. Our results indicate that j. Curcas seeds suffer adelay in germination under saline conditions and that reduced seedling growth and development occur when they are subjected to sodium chloride solution with an electrical conductivity of 6 ds -1. It thus appears that salt stress interferes with the physiological processes occurring in jatropha seeds.

Nogueira N.W.,Laboratorio Of Analise Of Sementes | de Freitas R.M.O.,Laboratorio Of Analise Of Sementes | Torres S.B.,Laboratorio Of Analise Of Sementes | Leal C.C.P.,Laboratorio Of Analise Of Sementes
Journal of Seed Science | Year: 2014

The seed maturation process is genetically controlled and involves an arranged sequence of morphological and physiological changes extending from fertilization to its total independence from the mother-plant. These changes also include a set of preparatory phases for the germination process, which are characterized for the synthesis and accumulation of nutrient reserves. Thereby, this study was developed aiming at assessing development and physiological quality of cowpea seeds during maturation process. To this, the cowpea pods of cultivar BRS-Guariba were harvested from the tenth day after anthesis (DAA) until the twenty sixth DAA, with four days intervals. Immediately after each harvest, seeds were manually extracted from the pods and then subjected to the following determinations: moisture content, first count of germination, final germination percentage, length of shoots and roots, hypocotyl diameter, and seedling dry mass. The experiment was conducted in a completely randomized design, with five treatments (DAA), and four replications to each treatment. Results have shown that cowpea seeds have fairly fast physiological maturation, and that seeds harvested between 14 and 18 DAA have better vigor as well as higher germination rates; thus the harvest performed during this period does not cause damages to seeds. © 2014, Associacao Brasileira de Tecnologia de Sementes. All rights reserved.

Ribeiro R.C.,Laboratorio Of Analise Of Sementes | Matias J.R.,Laboratorio Of Analise Of Sementes | Pelacani C.R.,Laboratorio Of Germinacao | Dantas B.F.,Laboratorio Of Analise Of Sementes
Journal of Seed Science | Year: 2014

The aim of this study was to evaluate the effect of different abiotic stresses on the activity of antioxidant enzymes and on accumulation of proline in Erythrina velutina Willd. seeds during germination. Mulungu seeds were scarified and placed to germinate at constant temperatures of 15, 25, and 35 °C, moistened with distilled water, and exposed to 12 h of light. Other seeds were exposed to solutions of NaCl (EC of 0, 4, and 8 dS.m-1) and polyethylene glycol (osmotic potentials of 0.0, -0.2, and - 0.6 MPa) and maintained in a germination chamber set at 25 °C and 12 h photoperiod for seven days. At the end of each period of imbibition, the embryonic axis and cotyledons of the seedlings were collected separately and used to quantify proline content and the activity of antioxidant enzymes. These were detected in both the cotyledons and embryonic axis of the mulungu seeds. Antioxidant activity varied depending upon the type and degree of stress applied. It was concluded that under the aspect of the detoxification process, the mechanism found in mulungu seeds is more efficient when subjected to different temperatures followed by salt stress and water stress.

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