Flower nectary structure in Cornus alba L.

The structure of the floral nectaries of Cornus alba was studied using light microscopy as well as scanning and transmission electron microscopy. It was found that the nectary gland of white dogwood had the shape of a fleshy ring surrounding the base of the style of the inferior ovary. Nectar secretion occurs through slightly depressed stomata, evenly distributed in the epidermis of the nectary. The nectariferous tissue is composed of over a dozen layers of heterogeneously structured cells. Between groups of cells with a typical structure, characteristic for the secretory tissue, cells occur with degenerated content and a high degree of vacuolization. In the area of the nectary gland cells, no vascular tissue elements were observed. The nectary was irrigated by the vasculature of the flower receptacle.