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Offering more floral resources for urban bees can be achieved by growing ornamental bee plants. The aim of the present study was to evaluate selected Asteraceae ( Calendula officinalis 'Persimmon Beauty' and 'Santana', Centaurea macrocephala, Cosmos sulphureus, Dahlia pinnata, Tagetes patula, Tithonia rotundifolia, and Zinnia elegans) as pollen sources for pollinators. Under urban conditions in Lublin, SE Poland, the investigated plants flowered from late June to the end of October. The mass of pollen produced in florets and capitula was found to be species-related. The highest pollen amounts per 10 florets (10.1 mg) as well as per capitulum (249.7 mg) were found for C. macrocephala. The mass of pollen yielded by a single plant depended on both the pollen mass delivered per disk florets and the proportion of disk florets in capitulum, and the flowering abundance of the plants. A single plant of D. pinnata and a single plant of T. rotundifolia each produced the largest pollen mass. Mean pollen yield per 1m2 of a plot ranged from 6.2 g ( Z. elegans) to 60.7 g (D. pinnata). Pollen grains are tricolporate, with echinate exine, medium or small in size. They can be categorised as oblatespherical, spherical, and prolatespherical. The principal visitors to C. macrocephala, C. sulphureus, and C. officinalis were honey bees, whereas bumble bees dominated on T. rotundifolia and D. pinnata. A magnet plant for butterflies was Z. elegans. Among the investigated species, D. pinnata, C. macrocephala, and T. rotundifolia were found to be the most valuable sources of pollen flow for managed and wild bees. [ABSTRACT FROM AUTHOR]

Eighteen samples of honeys which were harvested over several beekeeping seasons from apiaries located in the area of the 'Kózki' Nature Reserve (central-eastern Poland) were the subject of the present study. The 'Kózki' Nature Reserve is included in the European Ecological Network Natura 2000 program. A microscopic analysis of the pollen sediment in the honeys showed the presence of 61 pollen types from 32 botanical families in the investigated material. There were represented by nectariferous (72.1%) and nonnectariferous plants (27.9%) and both entomophilous and anemophilous ones. The total number of pollen taxa in individual samples ranged from 13 to 37. The main sources of nectar from trees and shrubs were: Frangula alnus, Prunus, Robinia pseudacacia, Rubus, Salix, Tilia. The main sources of nectar from herbaceous plants were: Anthriscus, Brassicaceae, Caryophyllaceae, Centaurea cyanus, Taraxacum, and Trifolium repens. Four unifloral honeys (three fruit tree honeys and one lime honey) and fourteen multifloral honeys, with a significant percentage of pollen from several nectariferous plant taxa, were distinguished in the studied material. [ABSTRACT FROM AUTHOR]

Under the conditions of Lublin (central-eastern Poland), observations were conducted on the flowering of Caragana arborescens shrubs for two growth seasons as well as nectar and pollen production by the flowers of this species was investigated. The flowering period of Caragana arborescens began at the turn of April and May and lasted for 24 days, while for a single flower it was 6.30 ± 0.79 days. The average weight of nectar, sugars and pollen produced by 10 Siberian peashrub flowers was, respectively: 46.70 ± 8.39 mg, 22.79 ± 6.10 mg, and 4.45 ± 0.34 mg. The nectar sugar concentration amounted 49.60 ± 10.08%. Pollen grains reached average dimensions of 21.94 ± 0.76 µm x 21.52 ± 0.71 µm. During a growing season, one Caragana arborescens shrub can provide on average 101.8 g of nectar, 49.7 g of sugars, and 9.7 g of pollen. [ABSTRACT FROM AUTHOR]

A study on the flowering biology and pollen production of the common laburnum (Laburnum anagyroides Med.) was conducted under the conditions of Lublin during the period 2004 - 2006. The flowering of this species began in the second 10-day period of May and lasted for 2.5 - 4 weeks. The flowers of common laburnum are borne in showy golden-yellow pendulous racemes. They develop successively, starting from the base and moving to the tip of an inflorescence. During the growing season, one shrub produces 800 to 3200 racemes, with 14 to 35 flowers in a single raceme. On average, the flowering duration for a raceme was 12.8 days and 8.7 days for a single flower. Throughout the study years, the shrubs proved to be most attractive in the third 10-day period of May when they reached full bloom. The average weight of pollen produced was 6.08 mg per 10 flowers of Laburnum anagyroides, 14.02 mg per raceme, and 26.0 g per shrub. Pollen grains reached average dimensions of 24.01 μm × 24.26 μm. [ABSTRACT FROM AUTHOR]