No abstract

No abstract

No abstract

The composition and seasonal distribution of airborne pollen grains in the atmosphere of Bahía Blanca, Argentina, has been studied between June 2001 and December 2003 using the Rotorod sampler (model 40). The results show that the main pollen types during this period were Cupressaceae, Fraxinus, Myrtaceae, Poaceae, Amaranthus/Chenopodiaceae, Pinus, Urticaceae, Ulmus, Olea and Styphnolobium. The highest concentrations occurred from August to December (end of winter and spring), accounting for 80% of the total annual pollen count. The greatest diversity was found in the spring, with the major of pollen coming from short-flowering plant types, such as Populus, Acer, Platanus, Juglans, Tamarix, Ailanthus and Typha. The potential sources of pollen from woody ornamental species are Cupressus sempervirens, Eucalyptus camaldulensis and Fraxinus pennsylvanica. whereas those from herbaceous species are the Chenopodiaceae and Poaceae, which are found within the city and also in the surrounding natural vegetation, and the Urticaceae, which are only present in the city. Marked annual differences were noted during the study period. The increase in 2002 may have been due to the abundant rainfall that occurred prior to the spring season, which would have favored the vegetative stage and flower development of plants. The decrease in pollen concentration in 2003 was mainly due to low rainfall throughout the year.

Seeds of Cucurbita maxima, C. moschata and their interspecific hybrids were used to evaluate the intrapopulational and interpopulational variation of their protein composition. Three immunoprecipitating systems common to all the studied samples were detected by the Ouchterlony technique. Fourteen protein bands were identified by polyacrylamide gel electrophoresis (PAGE) whereas 23 bands were identified by sodiumdodecylsulfate (SDS)-PAGE. Using Western blotting (WB) also 23 bands were detected. The Jaccard's index of similarity calculated from SDS-PAGE and WB varied between 91 and 100 % for all the compared pairs of samples. These results demonstrate a high uniformity in the protein composition of all the samples and do not allow for their clear characterization.