Main Difference – Endodermis vs Epidermis
Endodermis and epidermis are two cell layers found in the stem and root of the plant. The endodermis is found between the cortex and the vascular tissue. The epidermis produces the outer boundary between the plant and the external environment. The main difference between endodermis and epidermis is that endodermis is an inner cell layer whereas epidermis is the outermost layer of cells. The endodermis consists of tightly packed, single layer of cells. It separates the vascular tissues from the cortex. The epidermis is a thick single layer of cells. It is also called the cuticle and protects the plant from water loss and allows gas exchange.
Key Areas Covered
1. What is Endodermis
– Definition, Characteristics, Function
2. What is Epidermis
– Definition, Characteristics, Function
3. What are the Similarities Between Endodermis and Epidermis
– Outline of Common Features
4. What is the Difference Between Endodermis and Epidermis
– Comparison of Key Differences
Key Terms: Casparian Strip, Cortex, Endodermis, Epidermal Cells, Epidermis, Guard Cells, Suberin, Trichomes, Vascular Bundle
What is Endodermis
The epidermis is the inner cell layer of the cortex that surrounds the vascular bundle of the stem and root of a plant. The epidermis is a single layer of cells in both root and stem. The root endodermis is significant in plants since it consists of a Casparian strip. The Casparian strip develops as the first stage of the development of the endodermis. The radial and the transverse walls of the endodermal cells contain the Casparian strip, preventing the flow of water in or out of the stele through the apoplast. The Casparian strip occurs in higher plants from ferns. During the second stage, a thin layer of suberin (suberin lamellae) encases the whole endodermal cell. During the third stage, cellulose is deposited on the tangential walls over the suberin lamellae.
Figure 1: Endodermis
The endodermal cells in the stem ensure the flow of substances only through the vascular bundle. The U-shaped endodermal cells of the stem are shown as a red color ring in figure 1.
What is Epidermis
The epidermis is the outermost layer of a plant. It is found in every part of the plant such as stem, root, leaves, fruit, flower, and seed. The four types of cells in the epidermis are epidermal cells, subsidiary cells, guard cells, and trichomes. The epidermis forms the barrier between the plant and the external environment. The epidermal cells secrete a waxy substance called cuticle, which protects the plant from mechanical injuries. The cuticle also prevents water loss. The epidermis also regulates the gas exchange. The guard cells in the epidermis form the tiny pores called stomata, which allow the gas exchange. The root epidermis secretes organic compounds as well. The root epidermis plays a major role in absorbing water and mineral nutrients from the soil. The epidermal hair cells in the root, which absorb water, are called root hair cells. During the secondary growth of plants, the epidermis is replaced by the periderm in stem and root.
Figure 2: Epidermis and Endodermis
The epidermis in leaves is made up of parenchyma cells. The epidermis in leaves shows a dorsoventral anatomy; the epidermis in the upper and the lower surfaces of the leaf comprise a different anatomy to each other. The epidermal and the endodermal cell layers of a stem is shown in red in figure 2.
Similarities Between Endodermis and Epidermis
- Both endodermis and epidermis are two cell layers in the stem and root of the plants.
- Both endodermis and epidermis comprise a single cell layer.
- Both endodermis and epidermis make boundaries in the stem and root and have a protective role.
Difference Between Endodermis and Epidermis
Definition
Endodermis: Endodermis refers to the inner cell layer of the cortex of plants, which surrounds the vascular bundle.
Epidermis: Epidermis refers to the outermost layer of a plant, which is replaced by the periderm during the secondary growth in the stem and the root.
Location
Endodermis: Endodermis is found between the cortex and vascular tissue.
Epidermis: Epidermis is found in the outermost layer of the stem and root.
Cell Types
Endodermis: Endodermis contains tightly packed cells.
Epidermis: Epidermis contains cells with thick walls.
Composition
Endodermis: The endodermis contains a sheath of starch.
Epidermis: The epidermis contains a cuticle, and stomata.
Waxy Substances
Endodermis: The endodermis consists of a suberin and Casparian strips.
Epidermis: The epidermis consists of a cuticle.
Function
Endodermis: Endodermis separates the cortex from the vascular bundle.
Epidermis: Epidermis prevents water loss, allows gas exchange, and secretes organic compounds to the outside of the plant.
Conclusion
Endodermis and epidermis are two protective barriers in different parts of the body. Endodermis is found between the cortex and the vascular bundle. The endodermal cells consist of Casparian strips. The root endodermis plays a critical role in the conduction of water from the cortex to the xylem. The epidermis is the outermost cell layer of each part of the plant body. It consists of cuticles to prevent water loss from the plant. The epidermis allows the gas exchange and secretes organic compounds. The main difference between endodermis and epidermis is their relative positions in a plant and their functions.
Reference:
1.“Plants in Action.” 3.5.2 – Variable barriers: endodermis and exodermis | Plants in Action, Available here. Accessed 28 Aug. 2017.
2.“Epidermis.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 25 Nov. 2014, Available here. Accessed 29 Aug. 2017.
Image Courtesy:
1. “Iris germanicae – Schwertlilie,Wurzelquerschnitt,Tertiäre Endodermis,Leitbündel” By Truthlobby – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Monocot Root: Endodermis in Smilax” by Berkshire Community College Open Bioscience Image Library (Public Domain) via Flickr
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