SEM studies on sporangia and pollen morphology of Gingko biloba cultivars

The present study was conducted to illustrate the micromorphology of mature sporangia and pollen grains of four Ginkgo biloba cultivars: ‘Horizontalis’, ‘Lasiocarpa’, ‘Pragensis’ and ‘Tubifolia’ and is a continuation of earlier investigations on this subject. The sporophylls bear typically two pendulous sporangia, whereas three were found in one cultivar. The sporangia varied in shape from oval, elliptical elongate to boat-shaped and dehisced along a longitudinal slit. The sporangial walls are multilayered. The sculpture of the sporangium is rugose covered with wax crystals (tubules) and the endothecium shows clearly visible fibrous thickening on the wall. The pollen grains are monosulcate, the non-apertural surface is irregularly ridged (striate) or rugulate, with perforations and the germinal aperture (furrow) is covered with verrucae. The current study did not differentiate significantly four cultivars based on sporangia and pollen morphology. The micromorphological traits may be useful for identification and classification of fragments of fossil sporangia and pollen grains.