45 research outputs found
Temporal variations of vegetative features, sex ratios and reproductive phenology in a Dictyota dichotoma (Dictyotales, Phaeophyceae) population of Argentina
This paper addresses the phenology of a Dictyota dichotoma population from the North Patagonian coasts of Argentina. The morphology of the individuals was characterized, and analyses of the temporal variations of vegetative features, diploid and haploid life cycle generations and sex ratios are provided. Individuals, represented by growing sporophytes and gametophytes, occurred simultaneously throughout the year. Morphological variables showed temporal variation, except the width and height of medullary cells, which did not vary between seasons. All vegetative variables were significantly correlated with daylength. Besides, frond length, frond dry mass and apical and basal branching angles were significantly correlated with seawater temperatures. Vegetative thalli were less abundant than haploid and diploid thalli. Sporophytes were less abundant than male and female gametophytes. Male gametophytes dominated in May, August, October and January, and female gametophytes were more abundant in September, November, December, February and March. The formation of female gametangia showed a significant correlation with daylength, and the highest number of gametangia was registered in spring. In general, the male/female sex ratio varied between 1:2 and 1:1. Apical regions were more fertile than basal regions. Our data about frequency in the formation of reproductive structures and male/female ratios are the first recorded in the Dictyota genus and thus could not be compared with populations from other regions of the world. Significant morphological variation was observed in thalli of both life cycle generations, regarding length and dry mass, number of primary branches and branching basal angle. In general, all variables analyzed varied seasonally except cortical cell width.Fil: Gauna, Maria Cecilia. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia. Laboratorio de EcologĂa Acuática; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico BahĂa Blanca. Instituto Argentino de OceanografĂa (i); ArgentinaFil: Caceres, Eduardo Jorge. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia. Laboratorio de FicologĂa y MicologĂa; ArgentinaFil: Parodi, Elisa Rosalia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico BahĂa Blanca. Instituto Argentino de OceanografĂa (i); Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia. Laboratorio de EcologĂa Acuática; Argentin
Effect of microhabitat distribution and substrate roughness on barnacle Tetraclita stalactifera (Lamarck, 1818) settlement
Recommendation to include methyldibromo glutaronitrile in the European standard patch test series
Successional trajectory of the fouling community on a tropical upwelling ecosystem in southeast Rio de Janeiro, Brazil
Influence of upwelling and tropical environments on the breeding development of the intertidal barnacle Tetraclita stalactifera (Lamarck, 1818)
Comparison of rocky itertidal community sampling methods at northern coast of Rio de Janeiro State, Brazil
Avances en el conocimiento de la "mancha marrĂłn de las mandarinas" en Uruguay: estudios moleculares y biolĂłgicos. [p14*].
La mancha marrón de las mandarinas provocada por Alternaria alternata está presente en Uruguay. Bajo condiciones ambientales adecuadas, causa pérdidas económicas significativas en las mandarinas "Murcott" y "Nova". Con el objetivo de establecer un control integrado de la enfermedad, se realizaron diferentes estudios para conocer la influencia de los factores moleculares y biológicos determinantes para el establecimiento de la enfermedad