Germinação de sementes de Senna macranthera, Senna multijuga e Stryphnodendron polyphyllum

With the aim of contributing to the knowledge about the wood legume Senna macranthera and Senna multijuga (Caesalpinaceae), and Stryphnodendron polyphyllum (Mimosaceae) seed germination, the seed imbibition curves were determined to identify the coat-imposed dormancy, and the procedures to overcome it with mechanical or chemical scarification. The coat impermeability was present in these three species and, the mechanical scarification was the most effective treatment to break the dormancy (germination percent up 80%). In S. macranthera, the chemical scarification with sulfuric acid by 12 minutes showed similar efficiency to the mechanical scarification. A variation in coat permeability between non-scarified seeds of S. polyphyllum was observed.Com o objetivo de contribuir para o conhecimento sobre a germinação de Senna macranthera e Senna multijuga (Caesalpinaceae) e Stryphnodendron polyphyllum (Mimosaceae), foram determinadas as curvas de embebição das sementes para identificar o grau de dormência imposta pelo tegumento e os procedimentos para superá-la (escarificação mecânica ou química). Nas três espécies verificou-se a presença de tegumento impermeável e a escarificação mecânica foi o tratamento mais eficiente para quebrar a dormência, com porcentagem de germinação superior à 80%. Em S. macranthera a escarificação química em ácido sulfúrico durante 12 minutos apresentou eficiência similar à escarificação mecânica. Observou-se também uma variação na permeabilidade do tegumento entre as sementes não-escarificadas de S. polyphyllum

Caracteristicas fisicas e conteudo de proteinas de endospermas normal e sugary opaque-2, em espigas segregantes

Orientador: William Jose da SilvaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Sete tipos de espigas segregantes, com proporções distintas de endosperma do duplo mutante sugary opaque-2 e do tipo normal, foram produzidas artificialmente para investigar se as diferentes fontes de consumo geradas poderiam alterar características físicas e conteúdo de proteínas dos dois tipos de endospermas estudados. As espigas segregantes foram obtidas através da polinização de plantas sugary opaqu-2, com sete diferentes misturas de polem, preparadas com base no volume dos micrósporos. Os endospermas foram analisados na maturação fisiológica, em seis espigas individuais de cada grupo segregante. A quantidade de matéria seca (mg / endosperma), a porcentagem de umidade, a porcentagem de nitrogênio total e a porcentagem de zeina não foram alteradas nos diferentes grupos segregantes, tanto nos endospermas normais, como nos endospermas sugary opaque-2. Esses resultados demonstram que o acúmulo de matéria seca, de nitrogênio total e de zeina nos endospermas sugary opaque-2 e normal não foram influenciados pelos diferentes fluxos de nutrientes gerado nos grupos segregantes. As outras frações protéicas de Landry-Moreaus nos endospermas sugary opaque-2, à semelhança da zeina, não se mostraram diferentes em dois grupos segregantes distintos com 71,7 e 7,9% de endospermas normais. A quantidade de aminoácidos livres, apesar de ter sido estatisticamente menor no grupo com proporção de 71,7% de endospermas normais, revelou uma pequena diferança equivalente a 5,8% do total do nitrogênio no endosperma... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digitalAbstract: Seven groups of segregating ears with different normal to sugary opaque-2 endosperm ratios were produced artificially to see whether the different sink effects of the two maize types could influence each other in terms of physical or protein characteristics when developing side-by-side on the same ear. The segregating ears were produced after pollination of sugary opaque-2 plants using different pollen mixtures of normal and sugary opaque-2 pollen grains based on volume of microspore. Endosperms were analysed at maturity from six individual ears in each of the seven segregating groups. Dry Matter accumulation (mg / endosperm). Moisture percentage, total nitrogen percentage, and zein percentage were studied. These traits were not altered in both normal and sugary opaque-2 endosperms of the several segregating groups. The results demonstrate that dry matter, total nitrogen and zein accumulation in normal and sugary opaque-2 endosperms are not affected by different levels of nutrients taken into the segregating ears. The Landy-Moureaux fractions in the sugary opaque-2 endosperms also showed no difference between the two segregating groups containing 71,7 and 7,9% of normal endosperms. The amount of free amino acid, though statistically lower in the group with 71,7% of normal endosperms, showed small difference corresponding to 5,8% of total endosperm nitrogen... Note: The complete abstract is available with the full electronic digital thesis or dissertationsMestradoMestre em Ciências Biológica

Genetic variability of salt tolerance in populations of Stylosanthes humilis H.B.K. of different ecogeografic regions of the State of Pernambuco

Com o objetivo de estudar o comportamento de populações de Stylosanthes humilis em relação à salinidade e a variabilidade genética deste caráter nos estádios da germinação e do crescimento inicial foram analisadas seis populações provenientes de três regiões ecogeográficas do Estado de Pernambuco. Foram também realizadas eletroforeses de peroxidase, esteraae e malato desidrogenase para investigar a possível associação da tolerância salina com os padrões eletroforéticos. A tolerância salina das populações na germinação de sementes escarificadas foi avaliada em um gradiente de NaCl de 0 a 268 mM, através da porcentagem e da velocidade de germinação, e no crescimento inicial em solução nutritiva em quatro concentrações de NaCl, 0, 40, 80 e 120 mM, utilizando 11 caracteres. Para a estimativa de parâmetros genéticos foram realizados ensaios a nível de famílias na germinação com sementes escarificadas e não escarificadas e no estádio de crescimento inicial. Na germinação a tolerância salina é relativamente elevada, sendo que a porcentagem de germinação na maioria das populações só foi afetada por concentrações de NaCl acima de 134 mM e somente reduzida a 50% (G50) na média das populações na concentração de 268 mM, equivalendo ao potencial osmótico de -1,2 MPa. As populações nessa fase apresentaram-se muito diferentes quanto à tolerância salina, sendo também observada ampla variabilidade genética entre famílias nas populações do Sertão e em especial nas do Agreste, com coeficientes de variação genética de 21,3 a 52,3% e de determinação genotípica de 0,90 a 0,98, para sementes escarificadas. A tolerância salina das populações no estádio de crescimento inicial foi menor do que na germinação e não houve relação de tolerância das populações nas duas fases. A posição relativa de cada população quanto ao grau de tolerância variou de acordo com o caráter considerado, mas foi obtida boa separação das populações considerando o conjunto de caracteres. Para uma correta avaliação quanto à tolerância salina em genótipos dessa espécie é necessário considerar uma combinação de caracteres. Em comparação com outras espécies relatadas na literatura, algumas populações de S. humilis podem ser consideradas moderadamente tolerantes ao sal durante o crescimento inicial. A população Flores, a mais tolerante, apresentou para o caráter peso seco da parte aérea, em relação ao controle, o valor de 74% em 80 mM de NaCl e 37% em 120 mM e a população Janga, uma das mais sensíveis 52% em 80 mM e 25% em 120 mM, sendo o valor do ponto de inflexão (nível máximo em que não há alteração no crescimento), ao redor de 40 mM na média das populações. A magnitude dos coeficientes de variação genética e de herdabilidade no crescimento inicial dependeram do caráter e da população considerados, variando respectivamente de 0 a 56,5% e de 0 a 0,673. Houve relação entre o grau de variabilidade nas duas fases do ciclo de vida para todas as populações, com exceção de Caruaru, do Agreste. Houve também considerável variação dentro de famílias. As duas populações da Mata, em especial a Tamandaré, apresentaram pequena variabilidade genética nos dois estádios do ciclo de vida, o que está de acordo com a baixa variabilidade isoenzimática encontrada por MARCON (1988) nessas populações, sendo mais uma evidência de que ela deve ser causada pelo efeito do fundador, levando á deriva genética. Os níveis de variabilidade na tolerância salina entre e dentro da maioria das populações nas duas fases do ciclo de vida oferecem condições para a seleção e o melhoramento dessa espécie quanto a esse caráter. Essa variabilidade é também importante para a adaptação da espécie à níveis variáveis de salinidade. A eletroforese de isoenzimas revelou a associação de um alelo da peroxidase com a tolerância salina na germinação da população Caruaru. Entre as várias hipóteses para explicar essa associação, foram consideradas como mais plausíveis, o efeito do fundador, a redução no tamanho populacional e a possibilidade desse alelo ter uma origem recente.The behavior of six populations of Stylosanthes humilis from three ecogeographic regiona of the State of Pernambuco was analysed, in order to study the salt tolerance and the genetic variability of this character during germination and initial phase of growth. Electrophoresis for enzymes peroxidase , esterase and malate dehydrogenase was performed to investigate the possibility of association between salt tolerance and electrophoretic patterns. Germination percentage and germination rate were used to evaluate the salt tolerance of populations in scarified seeds in a gradient or 0 to 268 mM NaCl. The effect of salt in the initial phase of growth was evaluated in nutrient solution with four different NaCl concentrations of 0, 40, 80 and 120 mM NaCl, foreleven characters. The estimation of the genetic parameters was obtained for germination of scarified and non-scarified seeds and initial phase of growth at family level. Salt tolerance in germination is high. In most populations germination percentage was only affected at concentrations higher than 134 mM. A reduction of germination up to 50% was observed at the average of the populations at a concentration of 268 mM, the equivalent to a -1,2 MPa osmotic potential. The populations showed to be differences in salt tolerance and a large genetic variability was observed among families of Sertão populations, and specially in the Agreste populations, with a coefficient of genetic variation varying from 21,3 to 52.3% and a coefficient of genotypic determination varying from 0,90 to 0,98 for scarified seeds. Populations at the initial phase of growth showed less tolerance to salinity than at germination. No relation was observed in salt tolerance of the populations at both phases. The relative position of each population in relation to the degree of tolerance differed depending upon the character considered, but a good separation of populations could be achieved considering a set of characters. For the correct evaluation of genotypes of the species to salt tolerance, a combination of characters is necessary. Some populations of S.humilis could be considered moderately salt tolerant at the initial phase of growth, when compared to other species referred in the literature. Flores, the most tolerant population showed a shoot dry weight in relation to the control of 74% at NaCl concentration of 80 mM and 37% at 120 mM, while Janga, the most sensitive population showed 52% at 80 mM and 25% at 120 mM. The threshold (max. level with no growth alteration) is around 40 mM for the average of the populations. The extent of the coefficients of genetic variation and heritability in the initial phase of growth depends upon the character and the population analysed, varying from 0 to 56,5% and 0 to 0,673, respectively. A relation in variability exists in both phases of life cycle in all populations studied, with the exception of the Caruaru populations of Agreste. Considerable variation has been observed within families. The two populations from Mata, specially the Tamandaré population, showed little genetic variability in both phases of life cycle, which agrees with the low isozymatic variability found by MARCON (1988) in these populations, constituting one more evidence that this low variability level must be due to founder effect, leading to genetic drift. The level of variability for salt tolerance between and within most of the populations at both phases of life cycle offers the possibility of selection for this character. This variability is also important for the adaptation of the species to different salinity levels. Isozyme electrophoresis revealed the association of an peroxidase allele with salt tolerance at germination in the Caruaru population. Among several hypothesis which might explain this association, the founder effect, reduction of population size and the possibility that this allele might be of recent origin, were considered the most plausible

Genetic, morphological and spatial characterization of two populations of Mabea fistulifera Mart. (Euphorbiaceae), in different successional stages

Two populations of Mabea fistulifera (Euphorbiaceae) located at Rio Doce State Park (Minas Gerais, Brazil) in places characterized as in different successional stages, were investigated through genetic and ecological traits. Twenty randomly chosen individuals from each population had its genetic data assessed by 43 RAPD markers and were also evaluated through five morphologic traits and its spatial distribution. Both Shannon's index and AMOVA reveled that most of the genetic variation was found between individuals within populations and about 9% of variation was located between populations. Moreover, populations differed genetically, but presented similar values of genetic diversity. Morphologic data showed differences between populations. Significant correlations among matrix of genetic, geographic and morphologic distances were obtained considering both populations, and spatially closer individuals were more similar genetically, characterizing genetic substructured populations

Phylogeny of cissus (vitaceae) focusing on south american species

Widespread in the tropics, Cissus includes more than 300 species with great morphological diversity. Of the 78 species found in the New World, 64 grow in South America. This paper investigates phylogenetic relationships within Cissus, focusing on the South American species, insufficiently sampled in previous studies. Both plastid (trnL intron, trnL-F intergenic spacer, rps16) and nuclear ribosomal internal transcribed spacer (ITS) DNA sequences were analyzed with parsimony, likelihood and Bayesian inference. Divergence times were estimated with relaxed-clock Bayesian molecular dating. The evolution of leaf shape was reconstructed using parsimony. South American Cissus is resolved as not monophyletic. It consists of three clades: Cissus striata, Cissus trianae, and core Cissus. A clear separation between the Cissus striata clade and the other Cissus species was observed based on molecular and morphological characters. The relationship between the only species of the Cissus trianae clade and those of core Cissus is not clarified by our data. The geographic disjunction between the New and Old World taxa of core Cissus was estimated to have originated in the Late Eocene, and diversification in the Americas started in the Oligocene. In spite of the plasticity of leaf shape within species or individuals, this character is considered useful for infrageneric classification.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Genetic, morphological and spatial characterization of two populations of Mabea fistulifera mart. (Euphorbiaceae), in different successional stages.

Two populations of Mabea fistulifera (Euphorbiaceae) located at Rio Doce State Park (Minas Gerais, Brazil) in places characterized as in different successional stages, were investigated through genetic and ecological traits. Twenty randomly chosen individuals from each population had its genetic data assessed by 43 RAPD markers and were also evaluated through five morphologic traits and its spatial distribution. Both Shannon’s index and AMOVA reveled that most of the genetic variation was found between individuals within populations and about 9% of variation was located between populations. Moreover, populations differed genetically, but presented similar values of genetic diversity. Morphologic data showed differences between populations. Significant correlations among matrix of genetic, geographic and morphologic distances were obtained considering both populations, and spatially closer individuals were more similar genetically, characterizing genetic substructured populations

Fine-scale spatial genetic structure of Dalbergia nigra (Fabaceae), a threatened and endemic tree of the Brazilian Atlantic Forest

The Atlantic Forest is one of the most diverse ecosystems in the world and considered a hotspot of biodiversity conservation. Dalbergia nigra (Fabaceae) is a tree endemic to the Brazilian Atlantic Forest, and has become threatened due to overexploitation of its valuable timber. In the present study, we analyzed the genetic diversity and fine-scale spatial genetic structure of D. nigra in an area of primary forest of a large reserve. All adult individuals (N = 112) were sampled in a 9.3 ha plot, and genotyped for microsatellite loci. Our results indicated high diversity with a mean of 8.6 alleles per locus, and expected heterozygosity equal to 0.74. The co-ancestry coefficients were significant for distances among trees up to 80 m. The Sp value was equal to 0.017 and indirect estimates of gene dispersal distances ranged from 89 to 144 m. No strong evidence of bottleneck or effects of human-disturbance was found. This study highlights that long-term efforts to protect a large area of Atlantic Forest have been effective towards maintaining the genetic diversity of D. nigra. The results of this study are important towards providing a guide for seed collection for ex-situ conservation and reforestation programmes of this threatened species

Concordance between Phylogeographical and Biogeographical Patterns in the Brazilian Cerrado: Diversification of the Endemic Tree <i>Dalbergia miscolobium</i> (Fabaceae)

<div><p>Few studies have addressed the phylogeography of species of the Cerrado, the largest savanna biome of South America. Here we aimed to investigate the phylogeographical structure of <i>Dalbergia miscolobium</i>, a widespread tree from the Cerrado, and to verify its concordance with plant phylogeographical and biogeographical patterns so far described. A total of 287 individuals from 32 populations were analyzed by sequencing the <i>trnL</i> intron of the chloroplast DNA and the internal transcribed spacer of the nuclear ribosomal DNA. Analysis of population structure and tests of population expansion were performed and the time of divergence of haplotypes was estimated. Twelve and 27 haplotypes were identified in the cpDNA and nrDNA data, respectively. The star-like network configuration and the mismatch distributions indicated a recent spatial and demographic expansion of the species. Consistent with previous tree phylogeographical studies of Cerrado trees, the cpDNA also suggested a recent expansion towards the southern Cerrado. The diversity of <i>D. miscolobium</i> was widespread but high levels of genetic diversity were found in the Central Eastern and in the southern portion of Central Western Cerrado. The combined analysis of cpDNA and nrDNA supported a phylogeographic structure into seven groups. The phylogeographical pattern showed many concordances with biogeographical and phylogeographical studies in the Cerrado, mainly with the Cerrado phytogeographic provinces superimposed to our sampling area. The data reinforced the uniqueness of Northeastern and Southeastern Cerrados and the differentiation between Eastern and Western Central Cerrados. The recent diversification of the species (estimated between the Pliocene and the Pleistocene) and the ‘genealogical concordances’ suggest that a shared and persistent pattern of species diversification might have been present in the Cerrado over time. This is the first time that an extensive ‘genealogical concordance’ between phylogeographic and phytogeographic patterns is shown for the Cerrado biome.</p></div