With the help of active types of oxygen, extracellular enzymes and mechanical processes, Botrytis cinerea is capable of infecting plant tissue. Whereas no clear correlation was found between the activities of protease, pectolytic or other cell wall degrading enzymes and virulence, a positive correlation between pathogenicity and the intensity of active types of oxygen released was apparent in some isolates. It is assumed that these toxins result from the activity of glucose or xylose oxidases. Antioxidants inhibited the infection. It is concluded from these results, that active types of oxygen play a decisive role in the infection process.

No abstract

No abstract

No abstract

Various morphological and physiological characteristics, such as mycelial colour and appearance, mycelial growth rates, sporulation, pathogenicity on different hosts, activity of cell‐wall degrading enzymes, competitive ability and osmotic sensitivity of five dicarboximide‐resistant isolates of Botrytis cinerea were compared to those of their sensitive parent strains. There were only small reductions in mycelial growth rates of resistant strains as compared to the sensitive ones, whereas all of them showed greatly reduced rates of sporulation. With only one exception, the pathogenicity of the resistant isolates was reduced by varying extents compared with the sensitive parent strains. While the proteolytic activity of resistant strains tended to be higher, the activities of peclolytic enzymes were often lower than those of the sensitive isolates. In competition tests, resistant conidia often completely disappeared after a few passages on untreated plants. In only one of the resistant isolates tested so far was dicarboximide resistance related to a high osmotic sensitivity.

The soil's role in water flow partitioning is considerably modified in urban environments due to pavement and buildings, which interfere with the infiltration process. In this context, green areas gain importance as water infiltration spots. The aim of this research was to evaluate the contribution of soils of Francisco de Aguirre Park to water flow partitioning in Santiago del Estero city. To fulfill this, hydraulic soil properties such as sorptivity and hydraulic conductivity were determined in situ with a tension disc infiltrometer. Results indicated that different uses of the park affect significantly the hydraulic properties: areas used in a controlled way (using footpaths) exhibited high hydraulic conductivity values, whereas areas under intensive use (sports practicing, vehicle traffic) showed low values of this property. Finally, the comparison of soil's water infiltration capacities with intensity-duration-frequency curves of precipitation indicated that the soils of the park effectively contribute to water soil partitioning in Santiago del Estero city.

No abstract

Introducción y objetivos: En los hábitats salinos del Chaco semiárido es frecuente la forma de vida nanofanerófita y tipo de consistencia de hoja suculenta. Para determinar si la ocurrencia de ambos rasgos está relacionada a la salinidad del suelo, en este trabajo se describe la distribución de formas de vida y tipos de consistencia de hoja en relación a la salinidad del suelo entre dos comunidades leñosas. M&M: Se realizó un censo de leñosas y un muestreo de suelo en un matorral halófilo y en un bosque xerófilo sobre 25 subparcelas de 100 m2 en cada sitio. Se determinó pH y conductividad eléctrica del suelo hasta 50 cm de profundidad. Se describieron la cobertura y estratificación de vegetación, riqueza, abundancia e índice de diversidad para especies leñosas. Se evaluó el grado de similitud entre sitios según la cantidad de especies de nanofanerófita y de hoja suculenta compartidas, mediante el coeficiente de Sørensen. Las especies fueron agrupadas considerando simultáneamente su forma de vida y tipo de consistencia de hoja. La relación entre salinidad y grupos de leñosas se evaluó mediante un análisis de redundancia. Resultados: La riqueza, diversidad y complejidad estructural fueron mayores en el bosque. La similitud entre sitios fue baja. Las nanofanerófitas de hojas suculentas dominaron en el matorral con elevada salinidad y pH. Las microfanerófitas de hojas semi-coriáceas fueron dominantes en el bosque con baja salinidad y pH. Conclusión: La distribución de las nanofanerófitas de hojas suculentas presentó diferencias según la salinidad del suelo de ambas comunidades leñosas.