Characteristics of Drosera tentacles. I. Anatomical and cytological detail

Abstract

The area of merger between head and stalk was found to be anatomically much more diverse and to extend much deeper into the head than was previously thought. Interior cells of this transition zone, which we call the "neck area," were closely apposed to elements of the parenchyma bell of the head, and they contained many plasmodesmata in their walls. These features suggest that metabolites transported from the head to the leaf via the stalk largely follow an "interior route," especially since the inner stalk cells have some characteristics of conductive elements.The distinct cuticle, which covers the entire tentacle, was found to contain many pores in the area of the outer gland cells, with diameters up to 318 mμ. Complex tubular structures were detected in the outer pericline and upper anticline walls of the same cells. Together with the cuticle pores they were believed to account for the extreme permeability of the head.Intercellular spaces were detected in the middle and lower tentacle stalk. Since these spaces were not randomly distributed and were sometimes partially or completely closed, they were considered to be functional in tentacle bending.