Why is it particularly important for the endodermis to block transport in the specific location where it does?

Question

Quizplus · Accepted Answer

The endodermis is located at the innermost layer of the cortex and forms a barrier for materials entering the vascular tissues. It is important for the endodermis to regulate this access as the vascular tissues are responsible for transporting materials throughout the plant, such as water and nutrients. The endodermis helps to maintain a selective and regulated transport system in the plant by controlling what can pass through the vascular tissues.

Answer: B 
 The Casparian strip is a band of cell wall material found in the endodermis which is impervious to water and dissolved materials. This forces the materials to enter the cytoplasm of the endodermal cells in order to pass from the cortex to the vascular tissue. As such, the presence of the Casparian strip is a key mechanism for controlling the flow of materials in plants, and it is important for the endodermis to be present at this location in order to block transport and enforce the selective barrier created by the Casparian strip.

Answer: C 
 The endodermis is located at the base of the cortex, separating it from the vascular tissue in the roots. At this point, the cortex is permeable to water, but the endodermis forms an impermeable barrier that forces materials to pass through the selectively permeable plasma membrane of the endodermal cells. In this way, the endodermis can prevent harmful materials from entering the cortex and causing damage to the plant.

Answer: D 
 The endodermis plays a crucial role in the symplastic transport of materials in plants, as it is responsible for regulating access to the vascular tissues. The symplast refers to the continuous network of living plant cells interconnected by plasmodesmata, which allows for the movement of materials from cell to cell. By blocking symplastic transport, the endodermis can control what materials are able to enter the vascular tissues and be transported throughout the plant.

Why Is It Particularly Important for the Endodermis to Block