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The aim of performed experiments was to estimate variability of morphological, biological and chemical properties of Alopecurus pratensis and determine of possibilities of breeding for fodder and seed production purposes. In years 1994-1996, investigations were carried out on ecotypes and breeding materials of Brudzyński variety from own collection. The population of Alopecurus pratensis exhibits considerable variability within a wide range of traits which creates substantial selection possibilities of valuable material for breeding. The most interesting are two groups of plants isolated in ecotypes as well as in the Brudzyński variety. The first of them, tentatively called „green form", is characterised by a higher share of vegetative shoots in the tussock structure, bigger area of leaf blades, LAI index and yield and, consequently, better chemical composition and digestibility in comparison with plants of the "blue-green form". The green form creates considerable breeding possibilities of Alopecurus pratensis for forage purposcs. On the other hand, the blue-green form is characterised by a longer inflorescences, higher sced yield per tussock and unit area, smaller seed shedding and share of no shedding inflorescences per tussock at the moment of harvest. For that reason, the blue-green form is more suitable for breeding of this form for seed production purposes.
Investigations were carried out in 2008–2009 to assess the seed retention strength in spikelets of various Lolium multiflorum genotypes depending on their growth stages. The cultivars (Turtetra and Mitos), breeding strains (SZD 1021, SZD 1022, SZD 1023, SZD 216 and SZD 228) and ecotypes were used. With the aid of a special testing machine, retention strength of successive flowers/kernels in spikelets as well as strength required to rachilla breaking of selected spikelets were determined. It was found that the examined Lolium multiflorum genotypes were characterised by specificity regarding seed retention strength in spikelets. This biological feature was smaller for top flowers/kernels and increased with the movement down the spikelet. It was found that in the examined genotypes of Italian ryegrass the seed retention strength in spikelets in the analysed consecutive growth stages was smallest in spikelets situated in the upper part of the inflorescence and the highest in the lower part.
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Zmiany stężenia pyłku traw w atmosferze Poznania

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The aim of the study was to determine the concentrations of grass pollen during the vegetation season in the atmosphere of Poznań against the background of the content of pollen of other plants and mould fungi. Observations were conducted in 1997. Concentrations of pollen grains and spores of mould fungi in the atmosphere were assessed by the volumetric method. For this purpose, the Burkard apparatus (Seven-Day Recording Volumetric Spore Trap) was set up on the roof of the 8-storey high building of the Maximum College of the Agricultural University in Poznań. The continuous, 24-hour work of the apparatus made possible to monitor concentrations of allergenic pollen throughout the experiment. The tape was glued to a microscopic glass and evaluated under the light microscope. The number of pollen grains and mould spores on individual sections (2 mm per hour) of the tape allowed determining their concentration per 1 m3 of air. Microscopic evaluation was conducted every 24 hours, collecting analytical material from the trap at 10 a.m. in which pollen and spores were determined. From among many wind pollinated taksons of plants, species from the grass family - because of their long period of pollination and clinical significance - play an important role in the structure of allergenic pollen in the atmosphere of Poznań. The highest concentration of grass pollen was recorded during the period from the end of May to the end of the first decade of July. From then on, the concentration of grass pollen in the air dropped rapidly and remained on a low level, not exceeding 7.5 pollen grains calculated per 1 m3 air per 24 hours. The higher concentration of grass pollen was recorded on June 29th - 360.4 grains · m-3. In terms of 24-hour period, the highest concentrations of the pollen grains in the air on a day without rain occurred between 9 and 11 a.m., whereas the lowest - at night.
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