The innermost layer of the root cortex is the
a. Core
b. Pericycle
c. Endodermis
d. Pith

Verified step by step guidance

1. Understand the structure of a plant root: The root is composed of several layers, each with specific functions. The outermost layer is the epidermis, followed by the cortex, which is involved in storage and transport of nutrients.
2. Identify the innermost layer of the cortex: The cortex is the region between the epidermis and the vascular tissues. The innermost layer of the cortex is crucial for regulating the flow of water and nutrients into the vascular system.
3. Learn about the endodermis: The endodermis is the innermost layer of the cortex. It acts as a selective barrier, controlling the movement of substances into the vascular cylinder. It is characterized by the presence of the Casparian strip, a band of cell wall material that is impervious to water and solutes.
4. Differentiate between the options: The core is not a recognized layer in the root structure. The pericycle is a layer found just inside the endodermis, involved in the formation of lateral roots. The pith is typically found in the center of stems, not roots.
5. Conclude that the correct answer is the endodermis: Based on the structure and function of the root cortex, the endodermis is the innermost layer, making option c the correct choice.

Key Concepts

Root Cortex

The root cortex is a layer of tissue in plant roots located between the epidermis and the vascular tissues. It primarily functions in the storage of food and the transport of water and nutrients. The cortex is composed of parenchyma cells, which are loosely packed to allow for the movement of substances.

Endodermis

The endodermis is the innermost layer of the root cortex, characterized by a ring of cells that encircle the vascular cylinder. It plays a crucial role in regulating the flow of water and nutrients into the plant's vascular system, thanks to the Casparian strip, which is a barrier that forces substances to pass through the cell membranes.

Pericycle

The pericycle is a layer of cells found just inside the endodermis and is part of the vascular cylinder. It is involved in the formation of lateral roots and contributes to the plant's ability to grow and adapt to its environment. The pericycle can also play a role in secondary growth in some plants.