Pollen morphology of some sweet cherry cultivars observed by scanning electron microscopy

Morphology and ultrastructure of pollen grains were studied in five sweet cherry cultivars (‘Bing’, ‘Lapins’, ‘Sunburst’, ‘Stella’ and ‘Van’) in two years using scanning electron microscopy (SEM). All studied cultivars had isopolar, radially symmetric and tricolpate pollen grains. Length and width of pollen grains were the highest in ‘Sunburst’ (50.1 and 25.7 μm, respectively) and the lowest in ‘Bing’ (47.4 and 24.1 μm, respectively). Pollen shape in all the studied cultivars was identified as prolate. Colpus length and mesocolpium width varied in a range of 40.5-44.9 and 14.4-16.3 μm, respectively. All studied cultivars had striate exine ornamentation. Number of ridges 100 μm^-2 of the exine surface was significantly higher in ‘Bing’ (30.4) compared to those in other tested cultivars. Ridge and furrow width varied in a range of 0.28-0.35 and 0.26-0.30 μm, respectively. Pollen grains examination by SEM indicated that several morphological parameters (size and exine characteristics) can be used to distinguish sweet cherry cultivars.