What is the Difference Between Cortex and Epidermis in Plants

The key difference between cortex and epidermis in plants is that the cortex in plants is an unspecialized cell layer that lies between epidermis and vascular bundles in stems and roots, while the epidermis in plants is a specialized cell layer that covers the leaves, flowers, roots, and stems of plants.

Cortex is the inner cell layer of plants that surrounds the vascular bundle. It contains unspecialized cells that later transform into specialized endodermis. Epidermis, on the other hand, is the outermost cell layer of plants. Moreover, the epidermis is replaced by the periderm during the secondary growth of the stem and roots.

CONTENTS

1. Overview and Key Difference
2. What is Cortex in Plants
3. What is Epidermis in Plants
4. Similarities – Cortex and Epidermis in Plants
5. Cortex vs Epidermis in Plants in Tabular Form
6. Summary – Cortex vs Epidermis in Plants

What is Cortex in Plants?

Cortex is an unspecialized cell layer that lies between the epidermis and vascular bundles. Normally, it is quite large and extensive in roots. Cortex is also the surface layer of the non-fruiting part of the body of some lichens. The cortex is made up of thin-walled living parenchymatous cells with leucoplasts. Leucoplasts convert sugar into starch grains.

Figure 01: Cortex

The outer cortical cells acquire irregular thickened cell walls known as collenchymas cells. The outer cortical cells may contain chloroplasts as well. Generally, the cortex forms layers of cells made up of cork. The cortex is responsible for the transportation of material into the central cylinder of roots through diffusion. Moreover, it may also be used for food storage in the form of starch. The innermost layer of the cortex is known as the endodermis. The endodermis is composed of one layer of barrel-shaped cells. These cells are closely arranged without having intracellular spaces. The endodermal cells have thickened radial walls. These walls are known as Casparian strips, which were named after Caspary. Caspary was the one who first discovered these radial walls. Furthermore, fruticose lichens have one cortex encircling the branches and flattened leaf-like forms. Foliose lichens have different upper and lower cortices. Crustose, placodioid, and squamulose lichens have an upper cortex but no lower cortex. Leprose lichens are a type of lichen that lacks any cortex.

What is Epidermis in Plants?

The epidermis in plants is a specialized cell layer that covers the leaves, flowers, roots, and stems of plants. It is a single layer of cells. Moreover, it forms the boundary between the internal and external environment. The cells are composed of thin walls. The outer walls of the epidermal cells are not cutinized. The epidermis of most leaves shows dorsoventral anatomy. This means the upper and lower surfaces have somewhat different construction and may have different functions. Furthermore, woody stems and some other stems in potato (potato tuners) produce a secondary covering called the periderm, which generates from the epidermis. Normally, many epidermal cells prolong to form long hairy bodies. The epidermis of the root is called the epiblema.

Figure 02: Epidermis in Plants

The epidermis has several functions. It protects against water loss, regulates gas exchange, absorbs water and mineral nutrients, secretes metabolic compounds, and protects against pathogens.

What are the Similarities Between Cortex and Epidermis in Plants?

• Cortex and epidermis in plants are two plant cell layers.
• Both cell layers are in plants and absent in animals.
• They are present in stems and roots.

What is the Difference Between Cortex and Epidermis in Plants?

Cortex in plants is an unspecialized cell layer that lies between the epidermis and vascular bundles in stems and roots, while epidermis in plants is a specialized cell layer that covers the leaves, flowers, roots, and stems of plants. Thus, this is the key difference between cortex and epidermis in plants. Furthermore, the cortex in plants consists of multiple cell layers, while the epidermis in plants consists of a single cell layer.

The below infographic presents the differences between cortex and epidermis in plants in tabular form for side by side comparison.

Summary – Cortex vs Epidermis in Plants

Cortex and epidermis in plants are two plant cell layers. Cortex in plants is an unspecialized cell layer that lies between the epidermis and vascular bundles in stems and roots, while epidermis in plants is a specialized cell layer that covers the leaves, flowers, roots, and stems of plants. So, this is the key difference between cortex and epidermis in plants.

Reference:

1. “Epidermis (Outer Layer of Skin): Layers, Function & Structure.” Cleveland Clinic.
2. “Cortex in Plants.” Study.com.

Image Courtesy:

1. “Crassula ovata, vascular bundles labelled in cross-section” By Frank Vincentz – File:Crassula ovata5 ies.jpg (CC BY-SA 3.0) via Commons Wikimedia
2. “Leaf Tissue Structure” By Zephyris – Own work (CC BY-SA 3.0) via Commons Wikimedia

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