Question

The Casparian strip in dicots is most commonly found

• A. between cells of stem endodermis
• B. between secondary xylem and primary phloem
• C. on four sides of root endodermal cells
• D. below vascular cambium

Answer 1

The correct option is C on four sides of root endodermal cells

In roots, endodermis is a well-defined layer having characteristic thickenings in their walls. These thickenings are in the form of bands and appear on the tangential and radial walls of endodermal cells. The thickening or the bands are composed of suberin, making the endodermis impervious to water. Certain thin-walled cells called passage cells are endodermal cells without suberin thickening and help in water movement through the endodermis.


In stem, the Casparian thickenings are ill-defined or altogether lacking. In stem, the endodermal cells contain starch grain and hence the layer is called ‘starch sheath’.