This study is the first comparison of the morphology of pollen grains in ten cultivars of three species of the Taxus,
Torreya nucifera and Cephalotaxus harringtonia var. drupacea genera. The material came from the Botanical
Garden of Adam Mickiewicz University in Poznań, Poland. Each measurement sample consisted of 50 pollen
grains. In total, 750 pollen grains were analyzed. Light and electron scanning microscopy was used for the morphometric
observation and analysis of pollen grains. The pollen grains were inaperturate and classified as small
and medium-sized. They were prolate-spheroidal, subprolate to prolate in shape. The surface of the exine was
microverrucate-orbiculate, perforate in Cephalotaxus harringtonia var. drupacea, granulate-orbiculate, perforate
in all Taxus taxa and granulate-microverrucate-orbiculate, perforate in Torreya. The orbicules were rounded to
oval in surface view, and the size was considerably diversified. The pollen features were insufficient to distinguish
between individual Taxus members – only groups were identified. The values of the coefficient of variability of
three features (LA, SA and LA/SA) were significantly lower than the orbicule diameter. The pollen surface of all
Taxus specimens was similar, so it was not a good identification criterion. The pollen grains of the Taxus taxa
were smaller and had more orbicules than Cephalotaxus and Torreya. Palynological studies provided taxonomic
support for recognition of two different genera of the Cephalotaxaceae and Taxaceae families, which are closely
related.
The paper describes an experimental behaviour of the basalt fibre reinforced polymer composite by external strengthening to the concrete beams. The BFRP composite is wrapped at the bottom face of R.C beam as one layer, two layers, three layers and four layers. The different characteristics – are studied in – first crack load, ultimate load, tensile and compressive strain, cracks propagation, crack spacing and number of cracks etc. To – investigate, total of five beams size 100×160×1700 mm were cast. One beam is taken as control and others are strengthened with BFRP composite with layers. From this investigation, the first crack load is increased depending on the increment in layers from 6.79% to 47.98%. Similarly, the ultimate load carrying – capacity is increased from 5.66% to 20%. The crack’s spacing is also reduced with an increase in the number of layers.
Ornithogenic tundra developing near large seabird colonies with its dense vegetation creates sites for foraging, hiding and breeding of herbivores. Grazing, trampling and faeces deposition are considered as the most important ways that vertebrate herbivores influence the plants. Excrement deposition level informs us on the intensity of grazing i.e. foraging ground attractiveness. We have compared vertebrate herbivores’ faeces deposition (biomass) in the vicinity of big colonies of piscivorous (kittiwake Rissa tridactyla and Brünnich’s guillemot Uria lomvia) and planktivorous (little auk Alle alle) seabirds and the control area was in Hornsund, SW Spitsbergen. Much higher level of faeces deposition was recorded nearby seabird colonies as compared to the control area. These finding points out that vertebrate herbivores concentrate and feed more intensively on rich ornithogenic pastures. Number of herbivores and their faeces deposition level recorded nearby planktivorous seabird colony were greater as compared to those found nearby the colony of piscivores. The highest number of geese (Branta bernicla and Anser brachyrhynchus) and of their faeces biomass were found near the colony of planktivorous little auk, where distinct gradient in faeces deposition level along the colony-seashore axis was recorded. Reindeers Rangifer tarandus were observed in considerable numbers near the little auk colony, and were not recorded at all near cliff-nesting sites of kittiwakes and guillemots. Total deposition of excrements produced by geese was generally higher if compared to reindeers.
Flooding in the northern part of The Netherlands has caused serious economic threats to densely populated areas. Therefore a project has been carried out in a pilot area to assess the retention of water in two river basins as a way to reduce flooding. The physically-based groundwater and sur-face water model SIMGRO was used to model the hydrology of the basins. The model was calibrated using discharges and groundwater levels. Scenarios of measures to assess the possibility of retaining water in the basin were then defined and tested. The first measure was the retention of higher dis-charges using culverts or gates in the upstream part of the basin. The second measure was to make the streams shallower and thereby, increase flood plain storage. The last measure was flood water storage in a designated area in the downstream part of one basin. The analysis indicates that holding water in the upstream parts of the basins proved to be feasible and can result in significant reductions of peak flows.