Showing papers by "Federal University of Roraima published in 1999"

Self-incompatibility in passion fruit: evidence of two locus genetic control

Abstract: The self-incompatibility in yellow passion fruit was previously described as homomorphic sporophytic with monofactorial inheritance. Five progenies were obtained by bud-selfing. The plants of these progenies were selfed, reciprocally crossed within each progeny and crossed with known incompatible phenotypes to identify their phenotypic group. Fruit set was evaluated at the 7th day after pollination. Two progenies consisted of two self-incompatible groups, the other three formed three suck groups. The groups were identified as S1, S2, S3, S4, S5 and S6. The results provide evidence that the self-incompatibility of passion fruit is controlled by two loci, the S-gene and another, whose expression needs to be investigated.

Towards the thermochemical data of adducts involving glycine and cadmium chloride

Abstract: The prepared adducts CdCl2·xgly (x=1, 2 and gly=glycine) were characterized by infrared spectroscopy, thermogravimetry and differential scanning calorimetry. The infrared spectra showed that cadmium is coordinated through the carbonyl oxygen and the nitrogen atoms in the monoadduct and only carbonyl groups are involved in the bisadduct. The monoadduct melted before thermal degradation, suggesting the existence of a weaker intermolecular force as confirmed by standard molar enthalpy of dissolution values of 16.47±0.01 and 28.94±0.01 kJ mol−1 for 1:1 and 1:2 adducts, respectively. The standard molar enthalpy of reaction in the condensed phase: CdCl2(c)+xgly(c)=CdCl2·xgly(c); ΔrHmθ, gave −9.52±0.05 and −8.10±0.10 kJ mol−1 and the interaction in aqueous medium: CdCl2(aq)+xgly(aq)=CdCl2·xgly(aq); ΔaqHmθ, gave −0.13±0.07 and 0.00±0.14 kJ mol−1 for CdCl2·gly and CdCl2·2gly, respectively. From ΔrHmθ values the standard molar enthalpies of formation of the adducts were calculated as −912.48±6.60 and −1444.40±13.60 kJ mol−1. The enthalpies of decomposition 130.5±10.8 and 209.3±8.4, lattice −190.7±0.1 and 271.9±21.6 and reaction in the gaseous phase 599.8±16.8 and −329.3±5.0 kJ mol−1 for CdCl2·gly and CdCl2·2gly adducts were also calculated. From data of the reaction in the gaseous phase the mean enthalpy of the cadmium–oxygen bond was calculated as 82.3±5.0 kJ mol−1 for the bisadduct, which was restricted for a monoadduct due to the presence of distinct isomers.

Spherical Particles of Zirconia–Titania of Hexagonal Structure from a Neutral Amine Route

Abstract: Through the sol–gel process, using the so-called neutral amine route, spherical particles of 1:1 zirconia–titania were synthesized from zirconium(IV) and titanium(IV) butoxides as well as 1,12-diaminododecane as precursor species. The obtained product exhibited a hexagonal structure, as determinated by X-ray diffraction data. The obtained material was also characterized by thermogravimetry, differential scanning calorimetry, infrared spectroscopy, scanning electron microscopy, and surface area measurements. Despite the release of template molecules on heating, the spherical morphology was retained up to about 1200°C, at which the disruption of the spheres took place.

Inheritance of fruit color and pigment changes in a yellow tomato (lycopersicon esculentum mill.) mutant

Abstract: Neste trabalho avaliou-se a heranca da cor do fruto de um mutante natural da cv. Santa Clara, por meio da analise das geracoes F1 e segregantes, obtidas mediante cruzamento entre plantas da cv. Santa Clara normal e o mutante amarelo. A caracterizacao das plantas normais, mutantes e F1 foi feita com base na analise quantitativa dos pigmentos carotenoides e clorofila em flores, folhas e frutos verdes e maduros. Plantas F1 e provenientes do retrocruzamento com o progenitor normal apresentaram 100% de frutos vermelhos. A semelhanca entre os F1 reciprocos mostra que ha ausencia de heranca materna para as caracteristicas avaliadas. Em geracoes segregantes, as frequencias observadas foram compativeis com heranca monogenica pelo teste qui-quadrado, com dominância completa para o gene que confere cor vermelha. Os frutos amarelos apresentaram teores reduzidos de b-caroteno e licopeno, enquanto o hibrido apresentou teores intermediarios desses carotenoides quando comparados com o genotipo normal. Os niveis de clorofila em frutos verde-maduros e maduros mutantes foram menores que nos frutos normais, evidenciando o papel dos carotenoides sobre a fotoprotecao da clorofila. A concentracao de clorofila e carotenoides, em folhas e flores, nao foi afetada pela mutacao.

Myxomycetes do estado de Roraima, com especial referência para a estação ecológica de Maracá (Amajari - RR, Brasil)

Abstract: This survey raises the number of registers referred to the State of Roraima to 28 species of Myxomycetes. Of these, 24 were collected in the Maraca Ecological Reserve (Lat.3°l 5' - 3°35'N, Long. 61°22' - 61°58'WG). The following families and genera are registered: Ceratiomyxaceae (Ceratiomyxa, 4 sp); Cribrariaceae (Cribraria, lsp, Dictydium, lsp); Didymiaceae (Didymium, 2 sp); Enteridiaceae (Lycogala, 1 sp, Tubifera, 2 sp); Physaraceae (Craterium, 2 sp, Fuligo, 1 sp, Physarum, 2 sp); Stemonitaceae (Comatricha, 1 sp, Stemonitis, 4 sp); Trichiaceae (Arcyria, 3 sp, Hemitrichia, 2 sp, Perichaena, 1 sp, Trichia, Isp). One family, seven genera and eleven species are new records for the State; one of them, Ceratiomyxa sphaerosperma Boedj., is new for Roraima State and Northern Brazil. Comments and geographical distribution of these species are presented.

Entalpia reticular, entalpia de fusão e temperatura de fusão de adutos: algumas correlações empíricas utilizando DSC

Abstract: By using DSC data is shown that there are empirical correlations between lattice enthalpy, melting enthalpy and the temperature of melting for adducts, and that is possible, using only a single DSC curve, estimate the value of DM Hmq.

Estimating the value of the metal-ligand bond dissociation enthalpy (M-L) for adducts using empirical equations supported by TG data

Abstract: In this work is presented and tested (for 106 adducts, mainly of the zinc group halides) two empirical equations supported in TG data to estimate the value of the metal-ligand bond dissociation enthalpy for adducts: (M-O) = ti / g if ti (M-O) = (ti / g ) - 7,75 10-2 ti if ti > 420 K In this empirical equations, ti is the thermodynamic temperature of the beginning of the thermal decomposition of the adduct, as determined by thermogravimetry, andg is a constant factor that is function of the metal halide considered and of the number of ligands, but is not dependant of the ligand itself To half of the tested adducts the difference between experimental and calculated values was less than 5% To about 80% of the tested adducts, the difference between the experimental (calorimetric) and the calculated (using the proposed equations) values are less than 15%

Quality of tomato red fruit, cv. Santa Clara, its yellow mutant and respective F1 hybrid

Abstract: A caracterizacao de alguns atributos fisicos e quimicos de frutos de tomate da cv. Santa Clara, um mutante de fruto amarelo, e o hibrido F1 obtido do cruzamento entre eles, foi feita com base nos teores de b-caroteno, licopeno, vitamina C, pH, materia fresca, materia seca, diâmetro do fruto, diâmetro do pericarpo, acidez e solidos soluveis totais dos tecidos loculares e do pericarpo. Os frutos maduros amarelos apresentaram teores reduzidos de b-caroteno, licopeno e vitamina C, enquanto o hibrido apresentou teores semelhantes ao genotipo normal. Tanto o fruto mutante quanto o F1 apresentaram teor de pH menor que o do fruto normal. Nao houve diferenca significativa quanto a materia fresca e seca totais, diâmetro do fruto e do pericarpo e acidez. Os teores de solidos soluveis totais do pericarpo foram inferiores nos frutos do mutante amarelo e F1, em relacao ao genotipo normal, enquanto os teores de solidos soluveis totais da massa locular nao diferiram, estatisticamente, entre os genotipos.