Sampling methods and metereological factors on pests and beneficial organisms in strawberries

We characterize the population dynamics of pests and beneficial organisms in strawberries to assess the impact of two meteorological factors (temperature and precipitation) and define the most appropriate method for monitoring insects in strawberries crop. Population dynamics were monitored weekly using the plant beat method and Möericke traps in Albion strawberries. Measurements were taken in organic strawberry farms over two growing seasons, from March 26, 2010 to August 23, 2010 (first season - 2009/2010) and from October 4, 2010 to March 21, 2011 (second season - 2009/2010) in the municipality of Pinhais, Paraná state, southern Brazil (25º25'S; 49º08'W). We collected a total of 7,971 pests and 1,987 beneficial organisms. The most abundant pests were Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) in the first growing season and Tetranychus urticae (Koch) (Acari: Tetranychidae) in the second. Beneficial organisms from Acari, Araneae, and Hymenoptera parasitoids predominated in both seasons. Temperature and precipitation were the the primary climatic factor associated with the population variation of aphids. Populations of C. fragaefolii grew when the temperature was between 16°C and 25ºC. We found that plant beat was the fastest and most suitable method for strawberry pests monitoring since it captured insects that were effectively colonizing the plants. This study contributes to a better understanding of the entomofauna associated with cultivation of organic strawberry

Osmotic stress on genetically transformed tobacco plant seeds

Abstract: Salinity and water deficit limit the productivity of several crops; thus, studies related to the genetic transformation of seeds in a model plant, such as tobacco, can be an alternative to minimize negative impacts caused by environmental conditions. The purpose of this work was to evaluate the tolerance to osmotic stress of seeds from genetically transformed tobacco plants, with the introduction of the proline-synthesizer gene (p5csf129a), under salinity and water deficit conditions. To do so, five events with differences in proline content were selected, ranging from 0.70 to 10.47 µmoles.g-1 of fresh mass. The used saline concentrations were: zero (distilled water); 50; 100; 150 and 200 mmol.L-1 of NaCl, whereas for the water deficit, simulated with PEG 6000, the following osmotic potentials were used: zero (distilled water); -0.2; -0.4; -0.6 and -0.8 MPa. Each tested treatment was evaluated through germination, first germination count and germination speed index tests. It is possible to conclude that seeds from genetically transformed tobacco plants with overexpression of the gene p5csf129a, a proline synthesizer, are more tolerant to osmotic stresses. Tabacco seeds with a proline content of 10.47 µmol.g-1 showed a better perfomance, revealing higher physiological potential

Osmotic stress on genetically transformed tobacco plant seeds

<div><p>Abstract: Salinity and water deficit limit the productivity of several crops; thus, studies related to the genetic transformation of seeds in a model plant, such as tobacco, can be an alternative to minimize negative impacts caused by environmental conditions. The purpose of this work was to evaluate the tolerance to osmotic stress of seeds from genetically transformed tobacco plants, with the introduction of the proline-synthesizer gene (p5csf129a), under salinity and water deficit conditions. To do so, five events with differences in proline content were selected, ranging from 0.70 to 10.47 µmoles.g-1 of fresh mass. The used saline concentrations were: zero (distilled water); 50; 100; 150 and 200 mmol.L-1 of NaCl, whereas for the water deficit, simulated with PEG 6000, the following osmotic potentials were used: zero (distilled water); -0.2; -0.4; -0.6 and -0.8 MPa. Each tested treatment was evaluated through germination, first germination count and germination speed index tests. It is possible to conclude that seeds from genetically transformed tobacco plants with overexpression of the gene p5csf129a, a proline synthesizer, are more tolerant to osmotic stresses. Tabacco seeds with a proline content of 10.47 µmol.g-1 showed a better perfomance, revealing higher physiological potential.</p></div