The key difference between pericycle and endodermis is that pericycle is a cylinder of parenchyma or sclerenchyma cells that surround the ring of vascular bundles in the stele, while endodermis is the cylinder of cells that separate the cortex from the stele.
Pericycle and endodermis are two types of cell cylinders seen in plant roots. Endodermis and pericycle lie close to each other. Structurally, pericycle lies just inside the endodermis. The endodermis is the innermost cell cylinder of the cortex while pericycle is the outermost cell cylinder of stele. Therefore, endodermis separates the cortex from the stele while pericycle marks the outermost boundary of stele. Both layers of cells are composed of ground tissues. However, pericycle is multilayered while endodermis is a single cell layer.
CONTENTS
1. Overview and Key Difference
2. What is Pericycle
3. What is Endodermis
4. Similarities Between Pericycle and Endodermis
5. Side by Side Comparison – Pericycle vs Endodermis in Tabular Form
6. Summary
What is Pericycle?
The pericycle is a cylinder of parenchyma or sclerenchyma cells located just inside the endodermis. It is also the outermost cell layer that demarcates the stele of plants. Pericycle arises from the procambium. Hence, it can be considered as a part of vascular tissue.
Figure 01: Pericycle
Moreover, it has the ability to produce lateral roots. During secondary growth, pericycle contributes to the vascular cambium. The pericycle is also required for xylem loading in the root.
What is Endodermis?
The endodermis is the innermost cortical cell layer. Therefore, it is the boundary of cortex and it separates cortex from the stele. It is a single cell layer of barrel-shaped cells. It surrounds the pericycle of roots and stems. Similar to pericycle, endodermis is also a nonvascular tissue. It is composed of parenchyma cells.
Figure 02: Endodermis
The cell walls of the endodermis possess Casparian strips, which are water-impermeable deposits of suberin. Functionally, endodermis helps to regulate the flow of water and dissolved substances from the surrounding cortex. Moreover, endodermis stores starch in plants.
What are the Similarities Between Pericycle and Endodermis?
- Pericycle and endodermis are two cell layers found in plants roots and stems.
- They are ground tissues.
- Moreover, they are non-vascular tissues.
- Pericycle lies just inside the endodermis.
- Both pericycle and endodermis fulfil important functions in plants.
What is the Difference Between Pericycle and Endodermis?
Pericycle is the outermost cell layer of the stele in the root and stem of most plants. In contrast, endodermis is the innermost cortical cell layer that separates cortex from the stele. So, this is the key difference between pericycle and endodermis. Besides, another difference between pericycle and endodermis is that the pericycle is situated between the endodermis and the vascular bundles, while the endodermis is situated in between the pericycle and cortex.
Moreover, pericycle is multilayered while endodermis is a single cell layer. Also, pericycle is involved in xylem loading, lateral root initiation, and secondary growth. Meanwhile, endodermis helps to regulate the flow of water and dissolved substances from the surrounding cortex. Thus, this is the functional difference between pericycle and endodermis.
Below infographic summarizes the difference between pericycle and endodermis.
Summary – Pericycle vs Endodermis
Pericycle and endodermis are two types of cell layers unique to plants. Pericycle encircles the vascular tissues of roots and stem. It is the outermost cell layer of the stele. Meanwhile, endodermis surrounds the pericycle. Therefore, endodermis is the innermost cell layer of the cortex. Moreover, pericycle has one or two cell layers, while the endodermis is a single cell layer. Also, new lateral roots begin growth from the pericycle, while endodermis regulates the flow of water and dissolved substances from the surrounding cortex. Thus, this is the summary of the difference between pericycle and endodermis.
Reference:
1. Miyashima, Shunsuke, and Keiji Nakajima. “The Root Endodermis: a Hub of Developmental Signals and Nutrient Flow.” Plant Signaling & Behavior, Landes Bioscience, Dec. 2011, Available here.
2. “Top 4 Types of Ground Tissues in Plants (With Diagram): Botany.” Biology Discussion, 2 Feb. 2016, Available here.
Image Courtesy:
1. “Figure 30 03 03f” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia
2. “Ranunculus Root Cross Section” By Sadierath – Own work (CC BY-SA 4.0) via Commons Wikimedia