Abstract
Pollen grains vary widely in pollen shape, size, aperture type and exine sculpture among the taxa and within the taxon, which make them taxonomically important. They also contain several proteins, lipids and vitamins which are essential for the growth and developments of developing bee larvae. Quantification of these chemical constituents is important for the dietary purposes of honey bees. The present study deals with the morphology and chemical constituents of hand-collected pollen from four bee forage plants viz. Prunus cerasoides D.Don, Prunus persica (L.) Batsch, Pyrus pashia Buch.-Ham. ex D.Don and Rosa brunonii Lindl. from Garhwal Himalaya, Uttarakhand. The family represents a homogenous group with a tricolporate pollen aperture type in all the studied taxa. Pollen shape varied from sub-prolate to prolate-spheroidal with a smaller pollen size observed in Pyrus pashia (26.53±0.30 µm polar view and 24.20±1.04 µm equatorial view) and a larger one in Prunus persica (38.39±3.06 µm polar view and 36.41±1.34 µm equatorial view). Exine sculpture was psilate to striato-reticulate. Maximum crude protein (68.33±0.14 mg/g) and starch content (32.98±0.67 mg/g) were recorded in pollen of Prunus cerasoides and maximum free amino acid (13.78±0.71 mg/g) in Pyrus pashia. All chemical constituents were found to be significant except the amino acids which were non-significant at the 0.05* level. Results showed that pollen grains of these Rosaceous members contained high amount of crude protein and phenolic content as a bee food source for brood, which makes this family economically important.