Vega 2 lmu

Fixed samples of anthers with pollen grains were dehydrated in a successive 15, 30, 50, 70, 90, and 99.5% acetone series for 15 min at room temperature and twice in anhydrous acetone. Next, the pollen grains were critical point dried in liquid CO₂ using an Emitech K850 dryer (Quorum Technologies Ltd., Ashford, United Kingdom). Dried grains were transferred onto the microscope stage and sputter-coated with gold using an Emitech K550X device (Quorum Technologies Ltd., Ashford, United Kingdom). Observations of the surface of pollen grain sculpture (striae, perforations, microstriae) and photographic documentation were made using a Tescan Vega II LMU scanning electron microscope (SEM) (Tescan Orsay Holding, Brno, Czech Republic). The microscope was used for analysis of 100–150 pollen grains from each cultivar.

The surface and cross-section of the obtained films were analyzed by SEM (Tescan Vega II LMU, Tescan Orsay Holding, Brno, Czech Republic). The films were cut into small pieces and were fixed on double-sided adhesive carbon bands. The images were analyzed at an acceleration of 30 kV and were collected at 1 kx and 700× magnifications.

The cultured B. bassiana colonies were transferred onto slides with PVA mounting medium (PVA MTNG, BioQuip Products, Gladwick Street, CA, USA) and incubated at 25°C for 48 hours. The slides were observed under an optical microscope (DM500, Leica, Wetzlar, Germany) with 50× and 100× magnification. The morphology of the fungal pathogen’s synnema was studied under scanning electron microscopy (VEGA II LMU, Tescan Orsay Holding, Brno-Kohoutovice, Czech Republic) according to the taxonomic description of Rehner et al. [21 (link)].