Description:
A transverse section through the root of Acorus calamus shows that the cortex occupies by far the greatest area of primary body of the root. The outermost cell layer is the exodermis, generally with suberinized cell walls, which replaces the rhizodermis (the ‘true’ epidermal layer with root hairs) as it becomes worn away. The major part of the cortex, however, consists of aerenchyma (i.e. parenchyma cells which surround large intercellular spaces), which is typical of many aquatic and wetland plants. An endodermis with Casparian strips constitutes the innermost cortical layer and surrounds the central cylinder, which contains the pericycle (from which lateral roots may arise) and the vascular tissues (xylem and phloem). In monocot roots, xylem and phloem ridges are arranged in a circular fashion around the central pith (consisting of either parenchyma or thick-walled sclerified parenchyma).

Images:


Slide information:
- Embedding/Section & photo: Unknown/Olivier Leroux
- Paraplast section
- 10 micrometer
- Chrysoidin-astrablue staining (stains lignified cell walls red)