Characteristics of the surface of the epidermis in floral nectaries and the receptacle of mountain ash (Sorbus aucuparia L.)

The structure of receptacular surfaces of floral nectaries at two flowering stages and the structure of the outer surface of the receptacle of Sorbus aucuparia were investigated using scanning electron microscopy. Changes in the development of the cuticular epithelium of the nectary epidermis and differences in the degree of aperture of stomata were observed. Increased undulation of the gland surface was found during flower development. Numerous stomata were situated slightly below the level of epidermal cells of the nectary. At the pollination stage, open pores or pores surrounded by the cuticular epithelium were observed, as well as covered by dried secretion. Dried nectar in the form of patches was also visible on the surface of the gland. Stomata of the outer surface of the receptacle were located on protrusions and surrounded by the cuticular epithelium