Search

The three-year study on borage was conducted in Lublin, SE Poland. The aims were to investigate the flowering pattern and abundance, and the attractiveness (in terms of nectar and pollen production) for flower-visiting insects, mainly bees. Insect visitation and the effect of pollinators on fruit set and seed set were assessed as well. Flowering of borage started in the latter half of June and lasted eight weeks. The mean number of flowers · m−2 of the crop was 4570 per season. A borage flower produced on average 4.0 mg of nectar with a mean sugar concentration of 31.5%. The mean total sugar amount secreted in nectar was 1.2 mg. The pollen amount · flower−1 was 1.1 mg. A borage plant can supply insects with 1.1 g of nectar sugars and 1.1 g of pollen. The estimated nectar sugar yield and pollen yield per 1 m2 of the crop were similar, i.e. 5.2 g. Bees accounted for 73.0% of all insect visits to the borage flowers. The presence of insect pollinators increased the fruit set by 43.3% and seed set by 26.8%. [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]