Difference Between Guard Cell and Epidermal Cell

Guard Cell vs Epidermal Cell
 

The difference between guard cell and epidermal cell can be observed in the structure, content, and function of each cell type. The plant tissues can be categorized into three types; (a) dermal tissue found on external surfaces, (b) ground tissues which forms several internal tissues of the plant, and (c) vascular tissues that transports water and nutrients. The main function of the dermal tissue is to act as a protective layer. Ground tissue involves in photosynthesis, forms storage tissues, and provides structural support to the plant body. The dermal tissue forms epidermis, which consists of several types of cells including guard cells and proper epidermal cells. Epidermis is one layer of thick tissue in many plants and has direct contact with the outer environment. Depending on the age of the plant and the habitat or environmental conditions, the nature of the epidermis varies widely. For example, in desert plants, the epidermis has several layers of the cuticle in order to limit the water loss and provide protection from UV rays. Moreover, based on the functions, the epidermis contains several cell types. In this article, the difference between guard cell and the epidermal cell will be discussed.

What is a Guard Cell?

Guard cells are bean-shaped cells and are found in pairs, creating a mouth-shaped epidermal opening called stoma (plural stomata). These cells are surrounded by epidermal cells proper. Unlike the other epidermal cells proper, guard cells contain chloroplasts, thus photosynthetically active. Stomata mainly occur in the epidermis of the leaves, but sometimes they are found on the other parts of the plants such as stems or fruits. A stoma makes the passage of gas exchange between the plant tissues and the environment. In addition, it allows the water vapor diffusion. Guard cells control the rate of gas exchange and water diffusion by changing the size of the stomata.

Difference Between Guard Cell and Epidermal Cell

What is an Epidermal Cell?

The cells of the epidermis are called epidermal cells. These cells originate from the protoderm and cover the whole body of the plant. There are three types of specialized cells that occur in the epidermis, namely; guard cells, trichomes, and root hairs. Apart from these cells, the groundmass of the epidermis is made up of epidermal cells proper, which are considered as the least specialized cell type in the epidermis. The majority of the epidermal cells are tubular in shape and have little death. However, the shape may vary depending on the place they are found in the plant body. Epidermal cells found in many leaves, petals, ovaries and ovules contain wavy vertical cell walls. Cells contain plastids but contain very few grana and, therefore, deficient in chlorophyll. Thus, most epidermal cells are not photosynthetically active. However, plants in deep shade and submerged water plants have photosynthetically active epidermal cells.

Guard Cell vs Epidermal Cell

What is the difference between Guard Cell and Epidermal Cell?

Definitions of Guard Cell and Epidermal Cell:

Guard Cell: Guard cells are bean-shaped cells and are found in pairs, creating a mouth-shaped epidermal opening called stoma.

Epidermal Cell: Epidermal cells are the cells of the epidermis that originate from the protoderm and cover the whole body of the plant.

Characteristics of Guard Cell and Epidermal Cell:

Origin:

Guard Cell: Some of the epidermal cells are modified into guard cells.

Epidermal Cell: Epidermal cells originate from protoderm.

Ability of Photosynthesis:

Guard Cell: Guard cells can photosynthesis.

Epidermal Cell: Majority of epidermal cells are not photosynthetically active.

Amount:

Guard Cell: Guard cells are found only in some parts of the plant body.

Epidermal Cell: Main cell mass of the epidermis is made up of epidermal cells.

Function:

Guard Cell: Guard cells control the rate of gas exchange and water evaporation between plant body and environment.

Epidermal Cell: Epidermal cells form the protective tissue of the plant body.

Structure:

Guard Cell: Guard cells are bean-shaped cells and found as pairs in such a way to form an opening called stoma.

Epidermal Cell: Epidermal cells are usually tubular in shape, but that may vary depending on the place they are found in the plant body.

Content:

Guard Cell: Guard cells contain chloroplasts.

Epidermal Cell: Epidermal cells contain plastids but very few grana, thus they are deficient in chlorophyll.

 

Images Courtesy:

  1. Guard cells by Ayacop (CC BY 2.5)
  2. Leaf tissue structure by Zephyris (CC BY-SA 3.0)