Renato Delmondez de Castro

Effect of salinity on physic nut (Jatropha curcas L.) seed germination and seedling initial growth

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 sao paulo and parana. 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 a delay 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 m-1. It thus appears that salt stress interferes with the physiological processes occurring in jatropha seeds.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 a 1Submetido em 22/07/2009. Aceito para publicação em 06/01/2010. 2Bióloga, Pesquisadora Bolsista Desenvolvimento Científico Regional, FACEPECNPq, Embrapa Semiárido. Laboratório de Análise de Sementes, CP.23, CEP: 56302-970, Petrolina, PE. email: yara_andreo@yahoo.com. br. 3Biólogo, Mestrando. Embrapa Semiárido. Laboratório de Análise de Sementes, CP. 23, CEP: 56302-970, Petrolina, PE, email: armando. lopes@bol.com.br. 4Biólogo, Mestrando. Embrapa Semiárido. Laboratório de Análise de Sementes, CP. 23, CEP: 56302-970, Petrolina, PE, email: fabriciofrancisco2005@hotmail.com. 5Bióloga, Doutoranda Universidade Estadual de Feira de Santana, UEFS, Feira de Santana, BA, CEP: 44036-900, email: rconduru@gmail.com. 6Eng. Agr., Bolsista de Desenvolvimento Tecnológico Industrial CNPq, Embrapa Semiárido. Setor Floresta. CP. 23, CEP: 56302-970, Petrolina, PE, email: marcio.rannieri@cpatsa.embrapa.br. 7Eng. Agr., Professor Adjunto, Universidade Federal da Bahia, UFBA, CEP: 40170-115, Salvador, BA, email: rdelmondez@gmail.com. 8Eng. Agr.., Pesquisadora, Embrapa Semiárido. Laboratório de Análise de Sementes, CP. 23, CEP: 56302-970, email: bárbara@cpatsa.embrapa.br. Y. ANDRÉO-SOUZA et al. 84 Revista Brasileira de Sementes, vol. 32, no 2 p. 083-092, 2010 delay 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 m-1. It thus appears that salt stress interferes with the physiological processes occurring in jatropha seeds.

Physiological and biochemical responses of Ricinus communis seedlings to different temperatures: a metabolomics approach

BackgroundCompared with major crops, growth and development of Ricinus communis is still poorly understood. A better understanding of the biochemical and physiological aspects of germination and seedling growth is crucial for the breeding of high yielding varieties adapted to various growing environments. In this context, we analysed the effect of temperature on growth of young R. communis seedlings and we measured primary and secondary metabolites in roots and cotyledons. Three genotypes, recommended to small family farms as cash crop, were used in this study.ResultsSeedling biomass was strongly affected by the temperature, with the lowest total biomass observed at 20°C. The response in terms of biomass production for the genotype MPA11 was clearly different from the other two genotypes: genotype MPA11 produced heavier seedlings at all temperatures but the root biomass of this genotype decreased with increasing temperature, reaching the lowest value at 35°C. In contrast, root biomass of genotypes MPB01 and IAC80 was not affected by temperature, suggesting that the roots of these genotypes are less sensitive to changes in temperature. In addition, an increasing temperature decreased the root to shoot ratio, which suggests that biomass allocation between below- and above ground parts of the plants was strongly affected by the temperature. Carbohydrate contents were reduced in response to increasing temperature in both roots and cotyledons, whereas amino acids accumulated to higher contents. Our results show that a specific balance between amino acids, carbohydrates and organic acids in the cotyledons and roots seems to be an important trait for faster and more efficient growth of genotype MPA11.ConclusionsAn increase in temperature triggers the mobilization of carbohydrates to support the preferred growth of the aerial parts, at the expense of the roots. A shift in the carbon-nitrogen metabolism towards the accumulation of nitrogen-containing compounds seems to be the main biochemical response to support growth at higher temperatures. The biochemical changes observed in response to the increasing temperature provide leads into understanding plant adaptation to harsh environmental conditions, which will be very helpful in developing strategies for R. communis crop improvement research.

Depth of dormancy in tomato (Lycopersicon esculentum Mill.) seeds is related to the progression of the cell cycle prior to the induction of dormancy

Cell cycle activities are initiated following imbibition of non-dormant seeds. However, it is not known whether cell cycle related events other than DNA replication also remain suppressed in imbibed dormant seeds. The objective of this study was to demonstrate that the transitions between the non-dormant and dormant (both primary and secondary) states are reflected in cell cycle events, such as DNA replication and the changing patterns of the microtubular cytoskeleton involved in the processes of growth and development. The present studies were conducted on seeds from tomato (Lycopersicon esculentum cv. Moneymaker) that possessed primary dormancy or were manipulated to attain secondary dormancy. In addition, a non-dormant abscisic acid (ABA)-deficient mutant, sit w , was used. DNA replication, as measured by flow cytometry, and � tubulin accumulation, analysed by immunoblotting, were compared with immunocytological studies of active DNA synthesis and microtubular cytoskeleton formation. It is shown that the depth of dormancy, which distinguishes primary and secondary dormancy, may depend on the progression of the cell cycle prior to the induction of dormancy.

Metabolite profiling, antioxidant and antibacterial activities of Brazilian propolis: Use of correlation and multivariate analyses to identify potential bioactive compounds

The production of propolis by honeybees results from a selective collection of exudates from various plant species and present many potentialities in the pharmaceutical industry. The objective of this study was to investigate the chemical profile of Brazilian propolis, as well as their in vitro antioxidant and antibacterial activities. Gas chromatography-mass spectrometry was applied for chemical profiling of propolis extracts. Total phenolic compounds were quantified by Folin-Ciocalteu and antioxidant properties were assessed by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Antibacterial activity was assessed against Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteus. Correlation and multivariate statistical analysis were used to identify potential bioactive compounds in the extracts. Twenty-nine metabolites were identified along with 34 other metabolites that were classified into the following classes: triterpenoids (12), acetyltriterpenoids (3), sesquiterpenes (6), steroids (4), and hydrocarbons (9). The antioxidant capacity (IC50) ranged from 21.50 to 78.77μg/mL, whereas the content of total phenolic compounds ranged from 31.88 to 204.30mg GAE/g of dry weight. Total phenolic compounds and methyl retinoate showed a positive correlation with the antioxidant capacity, whereas tetradecanal, γ-palmitolactone and ethyl hydrocinnamate showed a negative correlation. Different sets of metabolites are shown to correlate with the antibacterial activity of the extracts, which is largely dependent on the type of microorganism. This innovative approach allowed us to identify likely bioactive compounds in the extracts, although the mechanism(s) underlying antibacterial activity encompass a complex trait, which might involve synergistic effects.

Compostos bioativos e atividade antioxidante de extratos brutos de espécies vegetais da caatinga

Summary This study aimed to determine the levels of bioactive phytochemicals in the seeds of native plant species from brushwood areas, Caesalpinia pyramidalis Tull, Erytrina velutina and Amburana cearensis, by the spectrophotometric quantification of the total phenolics, proanthocyanidins (condensed tannins), anthocyanins, total flavonoids and total carotenoids, and also investigate the correlation between the antioxidant activity measured using an in vitro model system of linoleic acid/ β-carotene and assess the effect of solvent extractors in the matrices studied. The levels of condensed tannins, analyzed using the acid butanol method, expressed in leucocianidin equivalents, were higher for Erytrina velutina, whereas for condensed tannins analyzed by the vanillin method and expressed as catechin equivalents, the highest values were found for C. pyramidalis. It was found that the levels of flavonoids, anthocyanins, carotenoids and total phenols were higher for C. pyramidalis as compared to the other species, besides presenting higher protein and lipid contents. The ethanol extracts of C. pyramidalis stood out for their greater antioxidant activity and correlation with the total phenolic content, thus presenting a potential source of phenolic compounds for application in the food and pharmaceutical industries.

Physiological quality of Gliricidia sepium (Jacq.) Steud. (Leguminosae - Papilionoideae) seeds subjected to different storage conditions

Studies of seed physiological processes represent the starting point for the sustainable utilization of native or cultivated plant species from the caatinga biome for which germination studies are still scarce. In order to determine adequate methods for the conservation of Gliricidia sepium seeds, the physiological quality of propagules exposed to different conditions and times of storage were examined. Recently collected seeds of G. sepium were analyzed immediately, while the other sample was stored for three, six, nine, or twelve months in plastic or paper bags under refrigeration or at room temperature for further analysis. The germination rates of seeds from each storage regime were determined and these rates compared to their water content. It was observed that germination capacity was directly related to changes in seed humidity. Storing seeds in plastic bags yielded the best conservation, mainly when they were stored at low temperatures. However, even at temperatures near 25°C it was possible to prolong seed viability when their water content was controlled through the use of impermeable packing.

Comportamento fisiológico de sementes de Myracrodruon urundeuva Fr. All. (Anacardiaceae) submetidas a fatores abióticos

The aim of this work was to evaluate germinating seeds of Myracrodruon urundeuva under different temperatures and hydrous potentials, the combination of both and the seeds viability after osmotic conditioning. The assay was conducted in a totally casual analysis with four repetition contained 50 seeds by treatment. The temperatures of 20, 25, 30, 33, 35 and 40 oC were tested with seeds soaked in distilled water. In another assay, the osmotic potentials of 0,0 (evidence) were tested; -0,2; -0,4; -0,6; -0,7; -0,8; -0,9; -1,0 e -1,2 MPa using PEG 6000 solutions. Based in these tests, it was established the best temperatures and the osmotic potentials of maximum germination, fifty percent of germination and no germination. After end of hydrous screening, no germinating seeds in no germinating potentials was tested for its capacity of germinating in water. Also, different temperatures were combined with different osmotic potentials. The seed germination Myracrodruon urundeuva starts in two days. At the temperature of 25 oC, it was obtained for maximum seed germination of the species at 33 oC for 50 % of the seeds germinated and at 40 oC, the germination was zero. Regarding to water restriction induced -0.2 MPa, it was an optimum germination potential, the potential of -0.7 MPa 50 % germination and from -0.9 MPa and germination was nil. The osmotic potentials of -0.9, -1.0 and -1.2 MPa, can be used for priming this species. The seeds of Myracrodruon urundeuva not tolerate the stresses of high temperatures and decreased water potential, concurrently, as they reduce the germination and seed vigor

Effect of osmopriming on germination and initial growth of Physalis angulata L. under salt stress and on expression of associated genes

This study aimed to evaluate the effects of priming on seed germination under salt stress and gene expression in seeds and seedlings of P. angulata L. After priming for 10 days, seed germination was tested in plastic trays containing 15 ml of water (0 dS m-1 - control) or 15 ml of NaCl solution (2, 4, 6, 8, 10, 12, 14 and 16 dS m-1). Fresh and dry weight of shoots and roots of seedlings were evaluated at 0, 2, 4, 6, 8 dS m-1. Total RNA was extracted from whole seeds and seedlings followed by RT-qPCR. The target genes selected for this study were: ascorbate peroxidase (APX), glutathione-S-transferase (GST), thioredoxin (TXN), high affinity potassium transporter protein 1 (HAK1) and salt overly sensitive 1 (SOS1). At an electroconductivity of 14 dS m-1 the primed seeds still germinated to 72%, in contrast with the non-primed seeds which did not germinate. The relative expression of APX was higher in primed seeds and this may have contributed to the maintenance of high germination in primed seeds at high salt concentrations. GST and TXN displayed increased transcript levels in shoots and roots of seedlings from primed seeds. Priming improved seed germination as well as salt tolerance and this is correlated with increased expression of APX in seeds and SOS1, GST and TXN in seedlings.

Metabolite profiling of Ricinus communis germination at different temperatures provides new insights into thermo-mediated requirements for successful seedling establishment

Ricinus communis seeds germinate to a high percentage and faster at 35 °C than at lower temperatures, but with compromised seedling establishment. However, seedlings are able to cope with high temperatures at later stages of seedling establishment if germination occurred at lower temperatures. Our objective was to assess the biochemical and molecular requirements of R. communis germination for successful seedling establishment at varying temperatures. For that, we performed metabolite profiling (GC-TOF-MS) and measured transcript levels of key genes involved in several energy-generating pathways, such as storage oil mobilization, β-oxidation and gluconeogenesis of seeds germinated at three different temperatures. We identified a thermo-sensitive window during seed germination in which high temperatures compromise seedling development, most likely by down-regulating some energy-generating pathways. Overexpression of malate synthase (MLS) and glycerol kinase (GK) genes resulted in higher starch levels in Nicotiana benthamiana leaves, which highlights the importance of these genes in energy-generating pathways for seedling establishment. Additionally, we showed that GABA, which is a stress-responsive metabolite, accumulated in response to the water content of the seeds during the initial phase of imbibition. Herewith, we provide new insights into the molecular requirements for vigorous seedling growth of R. communis under different environmental conditions.

Caracterização morfoanatomica e fisiológica de sementes e plântulas de Jatropha curcas L. (Euphorbiaceae)

Jatropha curcas L., conhecida popularmente como pinhao-manso, e uma especie encontrada em quase todas as regioes intertropicais do planeta. Possui sementes oleaginosas de importância medicinal e economica, sendo apontada atualmente como promissora fonte de materia-prima para a producao de biocombustiveis. Os objetivos deste trabalho consistiram em identificar as diferentes fases do processo de germinacao, descrever e ilustrar a morfologia de sementes e plântulas de Jatropha curcas L. e os aspectos anatomicos das sementes, relacionando as mudancas que ocorrem nos tecidos durante as fases de embebicao. Para a analise morfologica das sementes e plântulas, observaram-se os detalhes externos e internos. Para o estudo das fases de germinacao, foi realizado um ensaio para avaliar o comportamento das sementes durante a embebicao; para a analise anatomica, foram preparadas lâminas permanentes com cortes das sementes apos 0, 4, 24 e 72 h de embebicao. As sementes de Jatropha curcas L. sao endospermaticas, elipticas e anatropas com tegumento glabro, possuindo poros e fissuras em sua superficie. Os cotiledones sao foliaceos, com formato cordiforme e nervuras trinervias. A germinacao e do tipo fanerocotiledonar, epigea. Anatomicamente, as sementes sao albuminosas, sendo o tegumento constituido de celulas parenquimaticas, vacuoladas e poligonais com feixes vasculares e celulas esclereficadas. O endosperma e composto por celulas poliedricas ricas em substâncias de reserva, principalmente lipidios. Durante as fases de germinacao, observaram-se alteracoes no acumulo de grânulos de amido presentes no endosperma, bem como mudancas na organizacao dos seus feixes vasculares.