Plan the perfect garden with our interactive tool →

What Are the Functions of the Endodermis of a Root?

Thinkstock/Comstock/Getty Images

A plant's endodermis is a single cylindrical layer of cells that does not permit water to flow between the cells. Not all plants have an endodermis, but the structure plays an important role in transporting water from the ground via the roots up through the rest of the plant. The endodermis thus allows trees and other large plants to grow much taller than otherwise would be possible.

Structure of Endodermis

The most important property of the endodermis that it can regulate the concentration of solutions inside the root. Because there is no space between cells for water to travel, any water or ions that traverse the endodermis must go through two cell membranes. The endodermis therefore helps control the passage of water and ions from the root's cortex (the outer layer) and its stele (the inner layer). This control is critical to a plant's ability to transport water upward via root pressure.

Endodermis and Root Pressure

The stele contains a plant's xylem, tissue that moves water up the plant. Water flows upward in two ways. Plants without an endodermis use transpirational pull. Water evaporation in mesophyll tissue in the leaves creates surface tension in the xylem, prompting water to move up the plant. The endodermis increases a plant's ability to transport water upward by creating high concentrations of dissolved ions inside the root. Water with lower concentrations of ions outside the root then diffuse into the root, creating higher water pressure at the bottom of the plant and moving water up the plant.

  • The most important property of the endodermis that it can regulate the concentration of solutions inside the root.
  • Water evaporation in mesophyll tissue in the leaves creates surface tension in the xylem, prompting water to move up the plant.

Increased Possibilities for Plants

The additional water-transport capability allows plants with endodermis tissue to grow taller, because they are able to bring water and other nutrients to greater heights. Height carries several evolutionary advantages, including greater access to sunlight and increased protection from predators.

Other Functions

Because it forms a cellular seal around a plant's vascular tissue, the endodermis also helps prevent the entry of harmful organisms and chemicals into the plant.

Related Articles

Root Anatomy of Ranunculus
Root Anatomy of Ranunculus
Salt Water Effects on Plants
Salt Water Effects on Plants
How Plants Transport Water & Nutrients
How Plants Transport Water & Nutrients
How Does the Stem of a Water Lily Help it Grow In a Pond?
How Does the Stem of a Water Lily Help it Grow In a...
The Process of Transpiration in Vascular Plants
The Process of Transpiration in Vascular Plants
Importance of Water to Plants
Importance of Water to Plants
How Do Plant Cells Elongate?
How Do Plant Cells Elongate?
Root Rot in Citrus
Root Rot in Citrus
The Parts of a Daisy Plant
The Parts of a Daisy Plant
How to Repot Lucky Bamboo Plants
How to Repot Lucky Bamboo Plants
The Effects of Mineral Water on Plants
The Effects of Mineral Water on Plants
Active Ingredients in Miracle Grow
Active Ingredients in Miracle Grow
Does Overcrowding Plants Affect Their Growth?
Does Overcrowding Plants Affect Their Growth?
What Parts Do Non-Vascular Plants Have?
What Parts Do Non-Vascular Plants Have?
Garden Guides
×