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Abstract

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.
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Abstract

The Ebbabreen ice−cored moraine area is covered with a sediment layer of up to 2.5 m thick, which mostly consists of massive diamicton. Due to undercutting by lateral streams, debris flow processes have been induced in marginal parts of this moraine. It was recognized that the sedimentology of deposits within the deposition area of debris flows is the effect of: (1) the origin of the sediments, (2) the nature of the debris flow, and (3) post−debris flow reworking. Analysis of debris flow deposits in microscale (thin sections) suggests a common mixing during flow, even though a small amount of parent material kept its original structure. The mixing of sediments during flow leads to them having similar sedimentary characteristics across the deposition area regardless of local conditions ( i.e. slope angle, water content, parent material lithology). After the deposition of sediments that were transported by the debris flow, they were then reworked by a further redeposition process, primarily related to meltwater stream action.
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Abstract

We used via light and scanning electron microscopy to study the leaf epidermis of five Solidago taxa from south-western Poland. Light microscopy was employed to describe the epidermal surface, including stomatal types, the shape of epidermal cell walls, stomatal density, the distribution of stomata between the abaxial and adaxial epidermis, and stomatal guard cell length. From these observations we calculated the stomatal index (SI) and stomatal ratio (SR) as the basis for defining the type of leaf. From LM of transverse sections of leaf we described mesophyll structure, the presence of secretory canals, adaxial and abaxial epidermis thickness, and leaf thickness. We examined cuticular ornamentation, trichome features and epicuticular secretions by SEM. As determined by discriminatory analysis, the most important traits distinguishing these taxa were the stomatal index of the adaxial epidermis, leaf thickness, features of the walls of epidermal cells, and the presence and features of trichomes. On the basis of observations and measurements we created a key for distinguishing Solidago taxa.
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Abstract

In plants belonging to the Ranunculaceae the floral nectaries may differ in origin, location in the flower, shape and structure. In many cases they are defined as modified tepals or modified stamens. The nectary organs in this family are frequently termed "honey leaves," and staminodial origin is attributed to them. Gynopleural and receptacular nectaries are rarely found in Ranunculaceae. To date there are no reports on the structure of the nectary organs in plants of the genus Pulsatilla. We used light and scanning electron microscopy to study the location and structure of the nectaries in Pulsatilla slavica and P. vulgaris flowers. The staminodial nectaries were found to be nectar-secreting organs. The number of stamens per flower (102-398) increases with plant age. The share of staminodes is 12-15%. The staminodes are composed of a filament and a modified head. They are green due to the presence of chloroplasts in the epidermal and parenchymal cells. The parenchymal cells are in a loose arrangement. Stomata (3-20), through which nectar exudation occurred, were found only in the abaxial epidermis of the staminode head. The stomata are evenly distributed and have well-developed outer cuticular ledges. Some of them are immature during nectar secretion, with their pores covered by a layer of cuticle. During the activity of the nectariferous organs in the flowers, primary (on the staminode surface) and secondary nectar (at the base of tepals) are presented. The staminodes of the two Pulsatilla species show similar structural features and have similar shares in the androecium.
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