The chemical composition, amino acids and carbohydrates, of the pollen has been analysed in varieties grown in Hungary during the years 1993 at Kecskemet and 1995 at Cegléd and Pomáz. The distinction of 17 amino acids and 7 carbohydrates has been achieved. The aim of the study was to find criteria for the distinction of varieties.
... total content of amino acids varied between 15.53 and 20.54 %. The highest ratios represented the asparagine and the glutamine acids. The relative content in other amino acids was between 2 and 7 % of the total. The less frequent were cysteine and valine.
Studies were made on the composition of pollen loads of honeybees captured at the flowers of blooming pear trees in pear plantations. Also the foraging behaviour of honeybees was observed. Overwhelming majority of honeybees visiting the flowers of 13 pear cultivars in 1996 were pollen gatherers (95.6 per cent). Proportion of pure nectar gathere
...rs was as low as some 3.7 per cent and no more than 0.7 per cent performed mixed behaviour. The analysis of pollen loads of bees collected at pear flowers in blooming pear plantations showed that fidelity was as high as 89-90 per cent towards pear, higher than for another fruit species in other studies. Even those plant species that are regarded to be strong competitors of blooming fruit trees in the literature (Taraxacum officinale, Stellaria media, Lamium purpureum) were scarcely represented in the loads. Accordingly, honeybees can be much more important and more effective pollinating agents of pear cultivars than generally believed.