Micromorphology of the epidermis of the floral nectary of Rhododendron japonicum (A. Gray) J. V. Suringar ex E.H. Wilson.

Abstract

The conducted study related to the structure of the floral nectaries of Rhododendron japonicum (A. Gray) J. V. Suringar ex E. H. Wilson. The structure of the secretory epidermis of the nectaries was analysed by using scanning electron microscopy (SEM). Rhododendron japonicum develops the superior pistil with a 5-loculed ovary equipped in five ribs. The nectary gland is located in the lower part of the ovary. In the nectary regions located on the extension of the ribs of the ovary, stomata were very numerous. In the upper part of the nectary, stomata were arranged individually or in small clusters, whereas at its half- -height they formed stomatal areas. The stomata were at different growth stages. They were arranged in different directions. The stomata developed on the nectary surface according to the mosaic pattern. The stomata from the lower situated part of the nectary had a different structure than those occurring in the upper half of the nectary. The stomata in the nectaries of Rh. japonicum belong to the actinocytic type. The cuticle layer in the upper part of the nectary was better developed and had a characteristic sculpture, whereas in the lower part it was smooth.