Underground dicot roots typically do not possess a central pith.
Here's a more detailed explanation:
Dicot roots, unlike monocot roots and some dicot stems, have a different arrangement of vascular tissue in their central core. Instead of a large pith, which is a central region of parenchyma cells, the vascular cylinder in dicot roots is solid.
- Vascular Cylinder Arrangement: The xylem forms a star-shaped or cross-shaped structure in the center of the root. Phloem tissues are located between the arms of the xylem star.
- Absence of Pith: The central region is occupied entirely by vascular tissue (primarily xylem) with no pith present. Parenchyma cells are still present, but they function as connective tissue around the vascular tissues, rather than forming a distinct central pith region.
- Function of Parenchyma: Parenchyma cells located between the xylem and phloem facilitate the transport of water and nutrients laterally within the vascular cylinder.
In summary, the defining characteristic that underground dicot roots lack, in comparison to roots or stems that do have them, is a well-defined central pith region. The center of the dicot root is instead occupied by a solid core of vascular tissue.
