The floral nectaries of Hibiscus rosa-sinensis in. A morphometric and ultrastructural approach
Article first published online: 25 MAR 2008
Nordic Journal of Botany
Volume 9, Issue 1, pages 63–71, February 1989
How to Cite
Sawidis, Th., Eleftheriou, E. P. and Tsekos, I. (1989), The floral nectaries of Hibiscus rosa-sinensis in. A morphometric and ultrastructural approach. Nordic Journal of Botany, 9: 63–71. doi: 10.1111/j.1756-1051.1989.tb00987.x
- Issue published online: 25 MAR 2008
- Article first published online: 25 MAR 2008
The secretory hairs of Hibiscus rosa-sinensis nectaries have been studied ultrastructurally, particularly at stages before, during and after secretion. Morphometric cytology revealed considerable changes in the volume of endoplasmic reticulum (ER) and the vacuoles. At least three different forms of ER have been noticed, cisternal, tubular and vesicular. The intermediate cells of the hairs are ultrastructurally and morphometrically similar to the tip cell, suggesting their probable involvement both in a symplastic prenectar transport via the plasmodesmata and in nectar release into an extracellular space provided by the lateral cell walls. Nectar would then be apoplastically moving towards the tip cell, where it is forcibly expelled to the outside via transient pores of the cuticle.
Ultrastructural evidence indicates that ER is the cell compartment principally involved both in prenectar transport and nectar elimination. In the hair cells it provides a “secretory reticulum” mediating between prenectar accumulation and nectar release. Vacuoles are voluminous in the basal cells, and in all cell types of old nectaries. The results are discussed in relation with other plant glands, especially with the closely related Abutilon nectaries.