Developmental anatomy of flowers and resiniferous canals of Philodendron ornatum (Araceae)

 

Denis Barabe, Kshitij Trivedi, & Christian Lacroix

 

ABSTRACT

This study documents different stages of development of inflorescences and floral types (staminate, pistillate, sterile male, and atypical bisexual flowers) in Philodendron ornatum from an anatomical perspective, to track the development and structure of resiniferous canals, raphide idioblasts, and laticifers. Resiniferous canals and laticifers develop during early stages of initiation of floral primordia predominantly in the male and sterile male floral zones. As floral organs like stamens and staminodes are initiated, resiniferous canals become more apparent and line the area immediately below those organs. There are comparatively fewer resiniferous canals in the intermediate zone of the spadix. The vascular bundles are surrounded by laticifers throughout the axis of the inflorescence and raphide idioblasts are scattered throughout the aerenchymatous ground tissue. Mature resiniferous canals consist of one or two cell layers surrounding a central cavity. The internal layer corresponds to the epithelial cells that release resin. This type of canal corresponds to the more common type described in other species. Resiniferous canals were also observed with much less frequency on the outer periphery of the ground tissue just below the gynoecia of some female flowers. We conclude that there is a need to broaden this type of study to include a survey of more species to determine if there is a strong correlation between the anatomy of resiniferous canals and the phylogeny of species of Philodendron and Thaumatophyllum.

 

KEYWORDS

Resiniferous canals, inflorescence, anatomy, floral development, Philodendron ornatum, laticifers, raphides.