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

Elżbieta Weryszko-Chmielewska,Mirosława Chwil

doi:10.5586/aa.2007.005

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.

Highlights

This paper presents results of the study on the micromorphology of the nectary of this species conducted by using scanning electron microscopy
The nectary gland is located at the base of the ovary, where it forms rounded convexities by the particular ribs (Figs. 2, 5, 6)
The floral nectary of Rhododendron japonicum occurs at the base of the ovary, forming marked convexities by each of the five ribs of the ovary

Summary

Introduction

H. Wilson grows in natural habitats in Japan, where it is found in forest undergrowth. It was brought to Europe in the 19th century. In Poland it is cultivated as an ornamental shrub with pink, orange and brick-red flowers (Seneta and Dolatowski , 2004). Rh. japonicum is a valuable parent form due to its high frost resistance (Miyajima et al 2000; Okamoto et al 2006). Many hybrids and varieties are known, developed from multiple crosses, with different colours of flowers, from white to red (Seneta and Dolatowski , 2004)

Methods

Results

Conclusion