What is the role of casparian stripe?

Answer 1

To understand the purpose of the Casparian strip we must first understand what it is. The Casparian strip is found in the root of the plant. It is a barrier made of suberin, a waxy material that is impervious to water and dissolved minerals that is located in the transverse and radial walls of the endodermal cells - the final barrier between the outside and its various harmful materials and the vascular tissue.

Another thing we need to understand is the transport routes of water and its dissolved nutrients and minerals from root to vascular tissue.

There are three routes -

the symplastic route - a route that goes through the cytosol of cells (which is continuous thanks to cytoplasmic channels called plasmodesmata) exclusively. The cytosol of the cells is collectively referred to as the symplast.

the apoplastic route - a route that goes through the cell walls of cells (which are also continous) exclusively. The celle walls, extracellular spaces and dead interiors of tracheids and vessels are known collectively as the apoplast.

the transmembrane route - like the name suggests, a route that goes through both the symplast and the apoplast.

But recall that the Casparian strip is IMPERVIOUS to water! It forces water on apoplastic and transmembrane routes to cross the membrane of the endodermal cell to enter the vascular tissue via symplast. Why is this important? Recall again that the endodermal cells are the last gateway to the vascular tissue. When water is forced to detour into the cell because of the Casparian strip, it must cross the selectively permeable plasma membrane.

While the Casparian strip doesn't serve as a gateway, it has a vital purpose. It is kind of like a security guard in front of a metal detector at the airport - it ensures that everything going onto the plane (into the vascular tissue) is thoroughly checked.

Answer 2

the tangential as well as radial walls of endodermal cells have a deposition of water impermeable,waxy material-suberin/lignin in the form of casparian strips.It helps the flow of water from endodermal cells to xylem.

Answer 3

A Casparian strip is a band of cell wall material in plants that blocks the passive flow of materials, such as water and solutes, into the stele of the plant.

Answer 4

The casparian strip allows the plant to regulate what moves through its root or stem. This is how the plant interacts with its environment.

Answer 5

hydrophobic component in cell wall, it is composed of long chain olifens and polymeric units of phenolic acids such as caffeic and ferulic acids.

Answer 6

endodermis of the dicot root