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The aim of this study was to learn the strength of floral fidelity of honeybee colonies and to find what is the relationship between this trait and the amount of collected pollen. The observations were carried out in 2003 and 2004 on 10 honeybee colonies. The pollen was gathered from pollen loads collected using a pollen trap with a 5-mm screen mesh. A scanning electron microscope was used to view pollen grains in order to determine the number of plant species visited by the bees. The mean values of floral fidelity estimated individually for each experimental colony ranged from 40.1 to 75.7% in the first year, and from 45.1 to 67.3% in the second year of the studies. Correlation between floral fidelity and the quantity of collected pollen was observed in 60% of the colonies in the first year and in 70% in the second year. Recurrence of this relationship over the period of two years was found in only 30% of the studied honeybee colonies.
The investigations were carried out using light and scanning electron microscopy. The flowers of Elaeagnus commutata grow in clusters of 1-4 in the leaf axils. They are actinomorphic, four-lobed, with a single perianth that is yellow from the adaxial side, while the abaxial side is silvery-white. Peltate hairs of different structure are found on both surfaces of the sepals. The conical epidermal cells of the lobes are covered with a thick striated cuticle. Cylindrical hairs were observed on the edges of the lobes. Peltate hairs also grew on the style. The dish-shaped nectary gland is located at the base of the style. Nectar is secreted through numerous, evenly distributed stomata located above or at the level of other epidermal cells. Different stages of stomatal development are evidence of the asynchronous functioning of the stomata. The nectary consists of small epidermal cells and 5-6 layers of secretory parenchyma. The deeper layers of the gland are composed of larger cells of subglandular parenchyma in which vascular bundles supplying the nectary run. Honey bees were the main pollinators of silverberry. Ten silverberry flowers produced an average of 12 g of nectar with a sugar concentration in the 29.5-34.5% range. The weight of pollen produced by 10 flowers was 3.33 mg.
Hazel and alder bloom as one of the fi rst plants in climatic conditions of Poland. In the present study, detailed observations were made of the structure of fl owers of Corylus avellana L. and Alnus glutinosa (L.) Gaertn. Pollen yield of the abovementioned species was determined. The number of pollen grains in the theca, anther, fl ower and infl orescence was calculated. A comparison was made of the number of pollen grains of these taxa recorded during the atmospheric pollen seasons analysed over a period of 8 years in the conditions of Lublin. The study demonstrates that pollen yield of the common hazel infl orescence was 66 mg, whereas for black alder it was 120 mg. It was found that the number of pollen grains produced by the alder infl orescence was 2.2 times higher than by the hazel infl orescence. The atmospheric pollen season of the studied plant taxa was recorded at similar dates, but alder pollen was in much larger concentrations.
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